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Oracle VM
VirtualBox R
User Manual
Version 5.0.0 c 2004-2015 Oracle Corporation http://www.virtualbox.org Contents
1 First steps
1.1
Why is virtualization useful? . . . . . . . . . . . . . . .
1.2
Some terminology . . . . . . . . . . . . . . . . . . . . .
1.3
Features overview . . . . . . . . . . . . . . . . . . . . .
1.4
Supported host operating systems . . . . . . . . . . . .
1.5
Installing VirtualBox and extension packs . . . . . . . .
1.6
Starting VirtualBox . . . . . . . . . . . . . . . . . . . .
1.7
Creating your ﬁrst virtual machine . . . . . . . . . . .
1.8
Running your virtual machine . . . . . . . . . . . . . .
1.8.1
Starting a new VM for the ﬁrst time . . . . . .
1.8.2
Capturing and releasing keyboard and mouse
1.8.3
Typing special characters . . . . . . . . . . . .
1.8.4
Changing removable media . . . . . . . . . . .
1.8.5
Resizing the machine’s window . . . . . . . .
1.8.6
Saving the state of the machine . . . . . . . .
1.9
Using VM groups . . . . . . . . . . . . . . . . . . . . .
1.10 Snapshots . . . . . . . . . . . . . . . . . . . . . . . . .
1.10.1 Taking, restoring and deleting snapshots . . .
1.10.2 Snapshot contents . . . . . . . . . . . . . . . .
1.11 Virtual machine conﬁguration . . . . . . . . . . . . . .
1.12 Removing virtual machines . . . . . . . . . . . . . . . .
1.13 Cloning virtual machines . . . . . . . . . . . . . . . . .
1.14 Importing and exporting virtual machines . . . . . . .
1.15 Global Settings . . . . . . . . . . . . . . . . . . . . . .
1.16 Alternative front-ends . . . . . . . . . . . . . . . . . . .

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2 Installation details
2.1
Installing on Windows hosts . . . . . .
2.1.1
Prerequisites . . . . . . . . . .
2.1.2
Performing the installation . .
2.1.3
Uninstallation . . . . . . . . .
2.1.4
Unattended installation . . . .
2.2
Installing on Mac OS X hosts . . . . . .
2.2.1
Performing the installation . .
2.2.2
Uninstallation . . . . . . . . .
2.2.3
Unattended installation . . . .
2.3
Installing on Linux hosts . . . . . . . .
2.3.1
Prerequisites . . . . . . . . . .
2.3.2
The VirtualBox kernel module
2.3.3
Performing the installation . .
2.3.4
The vboxusers group . . . . .
2.3.5
Starting VirtualBox on Linux .
2.4
Installing on Solaris hosts . . . . . . .
2.4.1
Performing the installation . .
2.4.2
The vboxuser group . . . . . .
2.4.3
Starting VirtualBox on Solaris

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42

2

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Contents
2.4.4
2.4.5
2.4.6

Uninstallation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unattended installation . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conﬁguring a zone for running VirtualBox . . . . . . . . . . . . . . . .

3 Conﬁguring virtual machines
3.1
Supported guest operating systems . . . . . . . . . . . . . .
3.1.1
Mac OS X guests . . . . . . . . . . . . . . . . . . . .
3.1.2
64-bit guests . . . . . . . . . . . . . . . . . . . . . .
3.2
Emulated hardware . . . . . . . . . . . . . . . . . . . . . . .
3.3
General settings . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.1
“Basic” tab . . . . . . . . . . . . . . . . . . . . . . .
3.3.2
“Advanced” tab . . . . . . . . . . . . . . . . . . . .
3.3.3
“Description” tab . . . . . . . . . . . . . . . . . . .
3.4
System settings . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.1
“Motherboard” tab . . . . . . . . . . . . . . . . . .
3.4.2
“Processor” tab . . . . . . . . . . . . . . . . . . . .
3.4.3
“Acceleration” tab . . . . . . . . . . . . . . . . . . .
3.5
Display settings . . . . . . . . . . . . . . . . . . . . . . . . .
3.6
Storage settings . . . . . . . . . . . . . . . . . . . . . . . . .
3.7
Audio settings . . . . . . . . . . . . . . . . . . . . . . . . . .
3.8
Network settings . . . . . . . . . . . . . . . . . . . . . . . .
3.9
Serial ports . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.10 USB support . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.10.1 USB settings . . . . . . . . . . . . . . . . . . . . . .
3.10.2 Implementation notes for Windows and Linux hosts
3.11 Shared folders . . . . . . . . . . . . . . . . . . . . . . . . . .
3.12 Alternative ﬁrmware (EFI) . . . . . . . . . . . . . . . . . . .
3.12.1 Video modes in EFI . . . . . . . . . . . . . . . . . .
3.12.2 Specifying boot arguments . . . . . . . . . . . . . .

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4 Guest Additions
4.1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2
Installing and Maintaining Guest Additions . . . . . . . . . . . .
4.2.1
Guest Additions for Windows . . . . . . . . . . . . . . .
4.2.2
Guest Additions for Linux . . . . . . . . . . . . . . . . .
4.2.3
Guest Additions for Solaris . . . . . . . . . . . . . . . .
4.2.4
Guest Additions for OS/2 . . . . . . . . . . . . . . . . .
4.3
Shared folders . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.1
Manual mounting . . . . . . . . . . . . . . . . . . . . .
4.3.2
Automatic mounting . . . . . . . . . . . . . . . . . . .
4.4
Drag’n Drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4.1
Supported formats . . . . . . . . . . . . . . . . . . . .
4.5
Hardware-accelerated graphics . . . . . . . . . . . . . . . . . .
4.5.1
Hardware 3D acceleration (OpenGL and Direct3D 8/9)
4.5.2
Hardware 2D video acceleration for Windows guests . .
4.6
Seamless windows . . . . . . . . . . . . . . . . . . . . . . . . .
4.7
Guest properties . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.8
Guest control . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.9
Memory overcommitment . . . . . . . . . . . . . . . . . . . . .
4.9.1
Memory ballooning . . . . . . . . . . . . . . . . . . . .
4.9.2
Page Fusion . . . . . . . . . . . . . . . . . . . . . . . .

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5 Virtual storage
5.1
Hard disk controllers: IDE, SATA (AHCI), SCSI, SAS, USB MSC . . . . . . . . . .

81
81

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Contents
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10

Disk image ﬁles (VDI, VMDK, VHD, HDD)
The Virtual Media Manager . . . . . . . .
Special image write modes . . . . . . . . .
Differencing images . . . . . . . . . . . . .
Cloning disk images . . . . . . . . . . . . .
Host I/O caching . . . . . . . . . . . . . .
Limiting bandwidth for disk images . . . .
CD/DVD support . . . . . . . . . . . . . . iSCSI servers . . . . . . . . . . . . . . . . .

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6 Virtual networking
6.1
Virtual networking hardware . . . . . . . . . . . . . .
6.2
Introduction to networking modes . . . . . . . . . . .
6.3
Network Address Translation (NAT) . . . . . . . . . .
6.3.1
Conﬁguring port forwarding with NAT . . .
6.3.2
PXE booting with NAT . . . . . . . . . . . . .
6.3.3
NAT limitations . . . . . . . . . . . . . . . .
6.4
Network Address Translation Service (experimental)
6.5
Bridged networking . . . . . . . . . . . . . . . . . . .
6.6
Internal networking . . . . . . . . . . . . . . . . . . .
6.7
Host-only networking . . . . . . . . . . . . . . . . . .
6.8
UDP Tunnel networking . . . . . . . . . . . . . . . .
6.9
VDE networking . . . . . . . . . . . . . . . . . . . . .
6.10 Limiting bandwidth for network I/O . . . . . . . . . .
6.11 Improving network performance . . . . . . . . . . . .

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94
94
95
96
96
97
97
98
99
100
101
102
102
103
104

7 Remote virtual machines
7.1
Remote display (VRDP support) . . . . . . . . . . . . . . . . . . . . .
7.1.1
Common third-party RDP viewers . . . . . . . . . . . . . . .
7.1.2
VBoxHeadless, the remote desktop server . . . . . . . . . . .
7.1.3
Step by step: creating a virtual machine on a headless server
7.1.4
Remote USB . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1.5
RDP authentication . . . . . . . . . . . . . . . . . . . . . . .
7.1.6
RDP encryption . . . . . . . . . . . . . . . . . . . . . . . . .
7.1.7
Multiple connections to the VRDP server . . . . . . . . . . .
7.1.8
Multiple remote monitors . . . . . . . . . . . . . . . . . . . .
7.1.9
VRDP video redirection . . . . . . . . . . . . . . . . . . . . .
7.1.10 VRDP customization . . . . . . . . . . . . . . . . . . . . . . .
7.2
Teleporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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8 VBoxManage
8.1
Introduction . . . . . . . . . . . . . . . .
8.2
Commands overview . . . . . . . . . . .
8.3
General options . . . . . . . . . . . . . .
8.4
VBoxManage list . . . . . . . . . . . . .
8.5
VBoxManage showvminfo . . . . . . . .
8.6
VBoxManage registervm / unregistervm
8.7
VBoxManage createvm . . . . . . . . . .
8.8
VBoxManage modifyvm . . . . . . . . .
8.8.1
General settings . . . . . . . . .
8.8.2
Networking settings . . . . . . .
8.8.3
Miscellaneous settings . . . . .
8.8.4
Video Capture settings . . . . .
8.8.5
Remote machine settings . . . .

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136

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137
137
137
138
139
140
140
143
143
143
144
144
146
147
148
148
148
149
150
151
151
152
152
152
153
161
162
162
163
169

9 Advanced topics
9.1
VBoxSDL, the simpliﬁed VM displayer . . . . . . . . . . .
9.1.1
Introduction . . . . . . . . . . . . . . . . . . . .
9.1.2
Secure labeling with VBoxSDL . . . . . . . . . .
9.1.3
Releasing modiﬁers with VBoxSDL on Linux . .
9.2
Automated guest logons . . . . . . . . . . . . . . . . . .
9.2.1
Automated Windows guest logons . . . . . . . .
9.2.2
Automated Linux/Unix guest logons . . . . . . .
9.3
Advanced conﬁguration for Windows guests . . . . . . .
9.3.1
Automated Windows system preparation . . . .
9.4
Advanced conﬁguration for Linux and Solaris guests . . .
9.4.1
Manual setup of selected guest services on Linux
9.4.2
Guest graphics and mouse driver setup in depth
9.5
CPU hot-plugging . . . . . . . . . . . . . . . . . . . . . .
9.6
PCI passthrough . . . . . . . . . . . . . . . . . . . . . . .
9.7
Webcam passthrough . . . . . . . . . . . . . . . . . . . .
9.7.1
Using a host webcam in the guest . . . . . . . .
9.7.2
Windows hosts . . . . . . . . . . . . . . . . . . .
9.7.3
Mac OS X hosts . . . . . . . . . . . . . . . . . .
9.7.4
Linux and Solaris hosts . . . . . . . . . . . . . .
9.8
Advanced display conﬁguration . . . . . . . . . . . . . .
9.8.1
Custom VESA resolutions . . . . . . . . . . . . .

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171
171
171
171
172
173
173
174
177
177
178
178
178
179
180
181
181
182
182
183
183
183

8.9
8.10
8.11
8.12
8.13
8.14
8.15
8.16
8.17
8.18
8.19
8.20
8.21
8.22
8.23
8.24
8.25
8.26
8.27
8.28
8.29
8.30
8.31
8.32
8.33
8.34
8.35
8.36

8.8.6
Teleporting settings . . . . . . . .
8.8.7
Debugging settings . . . . . . . .
VBoxManage clonevm . . . . . . . . . . .
VBoxManage import . . . . . . . . . . . .
VBoxManage export . . . . . . . . . . . . .
VBoxManage startvm . . . . . . . . . . . .
VBoxManage controlvm . . . . . . . . . .
VBoxManage discardstate . . . . . . . . .
VBoxManage adoptstate . . . . . . . . . .
VBoxManage snapshot . . . . . . . . . . .
VBoxManage closemedium . . . . . . . . .
VBoxManage storageattach . . . . . . . . .
VBoxManage storagectl . . . . . . . . . . .
VBoxManage bandwidthctl . . . . . . . . .
VBoxManage showhdinfo . . . . . . . . . .
VBoxManage createhd . . . . . . . . . . .
VBoxManage modifyhd . . . . . . . . . . .
VBoxManage clonehd . . . . . . . . . . . .
VBoxManage convertfromraw . . . . . . .
VBoxManage getextradata/setextradata . .
VBoxManage setproperty . . . . . . . . . .
VBoxManage usbﬁlter add/modify/remove
VBoxManage sharedfolder add/remove . .
VBoxManage guestproperty . . . . . . . .
VBoxManage guestcontrol . . . . . . . . .
VBoxManage metrics . . . . . . . . . . . .
VBoxManage hostonlyif . . . . . . . . . . .
VBoxManage dhcpserver . . . . . . . . . .
VBoxManage debugvm . . . . . . . . . . .
VBoxManage extpack . . . . . . . . . . . .

5

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Contents
9.8.2

9.9

9.10
9.11

9.12
9.13
9.14

9.15
9.16
9.17
9.18
9.19
9.20

9.21

9.22

9.23
9.24

Conﬁguring the maximum resolution of guests when using the graphical frontend . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Advanced storage conﬁguration . . . . . . . . . . . . . . . . . . . . . . . . . .
9.9.1
Using a raw host hard disk from a guest . . . . . . . . . . . . . . . . .
9.9.2
Conﬁguring the hard disk vendor product data (VPD) . . . . . . . . .
9.9.3
Access iSCSI targets via Internal Networking . . . . . . . . . . . . . .
Legacy commands for using serial ports . . . . . . . . . . . . . . . . . . . . . .
Fine-tuning the VirtualBox NAT engine . . . . . . . . . . . . . . . . . . . . . .
9.11.1 Conﬁguring the address of a NAT network interface . . . . . . . . . .
9.11.2 Conﬁguring the boot server (next server) of a NAT network interface .
9.11.3 Tuning TCP/IP buffers for NAT . . . . . . . . . . . . . . . . . . . . . .
9.11.4 Binding NAT sockets to a speciﬁc interface . . . . . . . . . . . . . . .
9.11.5 Enabling DNS proxy in NAT mode . . . . . . . . . . . . . . . . . . . .
9.11.6 Using the host’s resolver as a DNS proxy in NAT mode . . . . . . . . .
9.11.7 Conﬁguring aliasing of the NAT engine . . . . . . . . . . . . . . . . .
Conﬁguring the BIOS DMI information . . . . . . . . . . . . . . . . . . . . . .
Conﬁguring the custom ACPI table . . . . . . . . . . . . . . . . . . . . . . . .
Fine-tuning timers and time synchronization . . . . . . . . . . . . . . . . . . .
9.14.1 Conﬁguring the guest time stamp counter (TSC) to reﬂect guest execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.14.2 Accelerate or slow down the guest clock . . . . . . . . . . . . . . . . .
9.14.3 Tuning the Guest Additions time synchronization parameters . . . . .
9.14.4 Disabling the Guest Additions time synchronization . . . . . . . . . .
Installing the alternate bridged networking driver on Solaris 11 hosts . . . . .
VirtualBox VNIC templates for VLANs on Solaris 11 hosts . . . . . . . . . . . .
Conﬁguring multiple host-only network interfaces on Solaris hosts . . . . . . .
Conﬁguring the VirtualBox CoreDumper on Solaris hosts . . . . . . . . . . . .
VirtualBox and Solaris kernel zones . . . . . . . . . . . . . . . . . . . . . . . .
Locking down the VirtualBox manager GUI . . . . . . . . . . . . . . . . . . . .
9.20.1 Customizing the VM manager . . . . . . . . . . . . . . . . . . . . . .
9.20.2 VM selector customization . . . . . . . . . . . . . . . . . . . . . . . .
9.20.3 Conﬁgure VM selector menu entries . . . . . . . . . . . . . . . . . . .
9.20.4 Conﬁgure VM window menu entries . . . . . . . . . . . . . . . . . . .
9.20.5 Conﬁgure VM window status bar entries . . . . . . . . . . . . . . . .
9.20.6 Conﬁgure VM window visual modes . . . . . . . . . . . . . . . . . . .
9.20.7 Host Key customization . . . . . . . . . . . . . . . . . . . . . . . . . .
9.20.8 Action when terminating the VM . . . . . . . . . . . . . . . . . . . . .
9.20.9 Action for handling a Guru Meditation . . . . . . . . . . . . . . . . .
9.20.10 Conﬁguring automatic mouse capturing . . . . . . . . . . . . . . . . .
9.20.11 Conﬁguring automatic mouse capturing . . . . . . . . . . . . . . . . .
9.20.12 Requesting legacy full-screen mode . . . . . . . . . . . . . . . . . . .
Starting the VirtualBox web service automatically . . . . . . . . . . . . . . . .
9.21.1 Linux: starting the webservice via init . . . . . . . . . . . . . . . . .
9.21.2 Solaris: starting the web service via SMF . . . . . . . . . . . . . . . .
9.21.3 Mac OS X: starting the webservice via launchd . . . . . . . . . . . . .
VirtualBox Watchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.22.1 Memory ballooning control . . . . . . . . . . . . . . . . . . . . . . . .
9.22.2 Host isolation detection . . . . . . . . . . . . . . . . . . . . . . . . . .
9.22.3 More information . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.22.4 Linux: starting the watchdog service via init . . . . . . . . . . . . .
9.22.5 Solaris: starting the watchdog service via SMF . . . . . . . . . . . . .
Other extension packs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting virtual machines during system boot . . . . . . . . . . . . . . . . . . .

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Contents

9.25
9.26
9.27
9.28
9.29
9.30
9.31

9.24.1 Linux: starting the autostart service via init . . . . . . . . . .
9.24.2 Solaris: starting the autostart service via SMF . . . . . . . . .
9.24.3 Mac OS X: starting the autostart service via launchd . . . . . .
VirtualBox expert storage management . . . . . . . . . . . . . . . . . .
Handling of host power management events . . . . . . . . . . . . . . .
Experimental support for passing through SSE4.1 / SSE4.2 instructions
Support for keyboard indicators synchronization . . . . . . . . . . . . .
Capturing USB trafﬁc for selected devices . . . . . . . . . . . . . . . . .
Conﬁguring the heartbeat service . . . . . . . . . . . . . . . . . . . . .
Encryption of disk images . . . . . . . . . . . . . . . . . . . . . . . . .
9.31.1 Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.31.2 Encrypting disk images . . . . . . . . . . . . . . . . . . . . . .
9.31.3 Starting a VM with encrypted images . . . . . . . . . . . . . .
9.31.4 Decrypting encrypted images . . . . . . . . . . . . . . . . . . .

10 Technical background
10.1 Where VirtualBox stores its ﬁles . . . . . . . . . . . . . . . .
10.1.1 Machines created by VirtualBox version 4.0 or later
10.1.2 Machines created by VirtualBox versions before 4.0
10.1.3 Global conﬁguration data . . . . . . . . . . . . . . .
10.1.4 Summary of 4.0 conﬁguration changes . . . . . . .
10.1.5 VirtualBox XML ﬁles . . . . . . . . . . . . . . . . . .
10.2 VirtualBox executables and components . . . . . . . . . . .
10.3 Hardware vs. software virtualization . . . . . . . . . . . . .
10.4 Paravirtualization providers . . . . . . . . . . . . . . . . . .
10.5 Details about software virtualization . . . . . . . . . . . . .
10.6 Details about hardware virtualization . . . . . . . . . . . . .
10.7 Nested paging and VPIDs . . . . . . . . . . . . . . . . . . . .

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11 VirtualBox programming interfaces

225

12 Troubleshooting
12.1 Procedures and tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.1.1 Categorizing and isolating problems . . . . . . . . . . . . . . . . .
12.1.2 Collecting debugging information . . . . . . . . . . . . . . . . . .
12.1.3 The built-in VM debugger . . . . . . . . . . . . . . . . . . . . . . .
12.1.4 VM core format . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.2 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.2.1 Guest shows IDE/SATA errors for ﬁle-based images on slow host ﬁle system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.2.2 Responding to guest IDE/SATA ﬂush requests . . . . . . . . . . . .
12.2.3 Performance variation with frequency boosting . . . . . . . . . . .
12.2.4 Frequency scaling effect on CPU usage . . . . . . . . . . . . . . .
12.2.5 Inaccurate Windows CPU usage reporting . . . . . . . . . . . . . .
12.2.6 Poor performance caused by host power management . . . . . . .
12.2.7 GUI: 2D Video Acceleration option is grayed out . . . . . . . . . .
12.3 Windows guests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.3.1 Windows bluescreens after changing VM conﬁguration . . . . . .
12.3.2 Windows 0x101 bluescreens with SMP enabled (IPI timeout) . . .
12.3.3 Windows 2000 installation failures . . . . . . . . . . . . . . . . .
12.3.4 How to record bluescreen information from Windows guests . . .
12.3.5 No networking in Windows Vista guests . . . . . . . . . . . . . . .
12.3.6 Windows guests may cause a high CPU load . . . . . . . . . . . .
12.3.7 Long delays when accessing shared folders . . . . . . . . . . . . .

7

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Contents
12.3.8
12.3.9

12.4

12.5

12.6
12.7

12.8

12.9

USB tablet coordinates wrong in Windows 98 guests . . . . . . . . .
Windows guests are removed from an Active Directory domain after restoring a snapshot . . . . . . . . . . . . . . . . . . . . . . . .
12.3.10 Restoring d3d8.dll and d3d9.dll . . . . . . . . . . . . . . . . . . . .
Linux and X11 guests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.4.1 Linux guests may cause a high CPU load . . . . . . . . . . . . . . .
12.4.2 AMD Barcelona CPUs . . . . . . . . . . . . . . . . . . . . . . . . . .
12.4.3 Buggy Linux 2.6 kernel versions . . . . . . . . . . . . . . . . . . . .
12.4.4 Shared clipboard, auto-resizing and seamless desktop in X11 guests
Solaris guests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.5.1 Older Solaris 10 releases crash in 64-bit mode . . . . . . . . . . . .
12.5.2 Solaris 8 5/01 and earlier may crash on startup . . . . . . . . . . .
FreeBSD guests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.6.1 FreeBSD 10.0 may hang with xHCI . . . . . . . . . . . . . . . . . .
Windows hosts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.7.1 VBoxSVC out-of-process COM server issues . . . . . . . . . . . . . .
12.7.2 CD/DVD changes not recognized . . . . . . . . . . . . . . . . . . . .
12.7.3 Sluggish response when using Microsoft RDP client . . . . . . . . .
12.7.4 Running an iSCSI initiator and target on a single system . . . . . . .
12.7.5 Bridged networking adapters missing . . . . . . . . . . . . . . . . .
12.7.6 Host-only networking adapters cannot be created . . . . . . . . . .
Linux hosts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.8.1 Linux kernel module refuses to load . . . . . . . . . . . . . . . . . .
12.8.2 Linux host CD/DVD drive not found . . . . . . . . . . . . . . . . . .
12.8.3 Linux host CD/DVD drive not found (older distributions) . . . . . .
12.8.4 Linux host ﬂoppy not found . . . . . . . . . . . . . . . . . . . . . .
12.8.5 Strange guest IDE error messages when writing to CD/DVD . . . . .
12.8.6 VBoxSVC IPC issues . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.8.7 USB not working . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.8.8 PAX/grsec kernels . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.8.9 Linux kernel vmalloc pool exhausted . . . . . . . . . . . . . . . . .
Solaris hosts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12.9.1 Cannot start VM, not enough contiguous memory . . . . . . . . . .
12.9.2 VM aborts with out of memory errors on Solaris 10 hosts . . . . . .

13 Security guide
13.1 General Security Principles . . . . . . . . . . . . .
13.2 Secure Installation and Conﬁguration . . . . . . .
13.2.1 Installation Overview . . . . . . . . . . .
13.2.2 Post Installation Conﬁguration . . . . . .
13.3 Security Features . . . . . . . . . . . . . . . . . .
13.3.1 The Security Model . . . . . . . . . . . .
13.3.2 Secure Conﬁguration of Virtual Machines
13.3.3 Conﬁguring and Using Authentication . .
13.3.4 Potentially insecure operations . . . . . .
13.3.5 Encryption . . . . . . . . . . . . . . . . .

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246

14 Known limitations
247
14.1 Experimental Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
14.2 Known Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
15 Change log
251
15.1 Version 5.0.0 (2015-07-09) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
15.2 Version 4.3.28 (2015-05-13) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254

8

Contents
15.3
15.4
15.5
15.6
15.7
15.8
15.9
15.10
15.11
15.12
15.13
15.14
15.15
15.16
15.17

Version 4.3.26 (2015-03-16)
Version 4.3.24 (2015-03-02)
Version 4.3.22 (2015-02-12)
Version 4.3.20 (2014-11-21)
Version 4.3.18 (2014-10-10)
Version 4.3.16 (2014-09-09)
Version 4.3.14 (2014-07-15)
Version 4.3.12 (2014-05-16)
Version 4.3.10 (2014-03-26)
Version 4.3.8 (2014-02-25) .
Version 4.3.6 (2013-12-18) .
Version 4.3.4 (2013-11-29) .
Version 4.3.2 (2013-11-01) .
Version 4.3.0 (2013-10-15) .
Older Change log details . .

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273

16 Third-party materials and licenses
16.1 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.2 Licenses . . . . . . . . . . . . . . . . . . . . . . . . . . .
16.2.1 GNU General Public License (GPL) . . . . . . . .
16.2.2 GNU Lesser General Public License (LGPL) . . .
16.2.3 Mozilla Public License (MPL) . . . . . . . . . . .
16.2.4 MIT License . . . . . . . . . . . . . . . . . . . .
16.2.5 X Consortium License (X11) . . . . . . . . . . .
16.2.6 zlib license . . . . . . . . . . . . . . . . . . . . .
16.2.7 OpenSSL license . . . . . . . . . . . . . . . . . .
16.2.8 Slirp license . . . . . . . . . . . . . . . . . . . .
16.2.9 liblzf license . . . . . . . . . . . . . . . . . . . .
16.2.10 libpng license . . . . . . . . . . . . . . . . . . .
16.2.11 lwIP license . . . . . . . . . . . . . . . . . . . .
16.2.12 libxml license . . . . . . . . . . . . . . . . . . .
16.2.13 libxslt licenses . . . . . . . . . . . . . . . . . . .
16.2.14 gSOAP Public License Version 1.3a . . . . . . . .
16.2.15 Chromium licenses . . . . . . . . . . . . . . . .
16.2.16 curl license . . . . . . . . . . . . . . . . . . . . .
16.2.17 libgd license . . . . . . . . . . . . . . . . . . . .
16.2.18 BSD license from Intel . . . . . . . . . . . . . .
16.2.19 libjpeg License . . . . . . . . . . . . . . . . . . .
16.2.20 x86 SIMD extension for IJG JPEG library license
16.2.21 FreeBSD license . . . . . . . . . . . . . . . . . .
16.2.22 NetBSD license . . . . . . . . . . . . . . . . . .
16.2.23 PCRE license . . . . . . . . . . . . . . . . . . . .
16.2.24 libfﬁ license . . . . . . . . . . . . . . . . . . . .
16.2.25 FLTK license . . . . . . . . . . . . . . . . . . . .
16.2.26 Expat license . . . . . . . . . . . . . . . . . . . .
16.2.27 Fontconﬁg license . . . . . . . . . . . . . . . . .
16.2.28 Freetype license . . . . . . . . . . . . . . . . . .
16.2.29 VPX License . . . . . . . . . . . . . . . . . . . .

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17 VirtualBox privacy information

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Glossary

313

9

1 First steps
Welcome to Oracle VM VirtualBox!
VirtualBox is a cross-platform virtualization application. What does that mean? For one thing, it installs on your existing Intel or AMD-based computers, whether they are running Windows,
Mac, Linux or Solaris operating systems. Secondly, it extends the capabilities of your existing computer so that it can run multiple operating systems (inside multiple virtual machines) at the same time. So, for example, you can run Windows and Linux on your Mac, run Windows Server
2008 on your Linux server, run Linux on your Windows PC, and so on, all alongside your existing applications. You can install and run as many virtual machines as you like – the only practical limits are disk space and memory.
VirtualBox is deceptively simple yet also very powerful. It can run everywhere from small embedded systems or desktop class machines all the way up to datacenter deployments and even Cloud environments.
The following screenshot shows you how VirtualBox, installed on a Mac computer, is running
Windows 8 in a virtual machine window:

In this User Manual, we’ll begin simply with a quick introduction to virtualization and how to get your ﬁrst virtual machine running with the easy-to-use VirtualBox graphical user interface.
Subsequent chapters will go into much more detail covering more powerful tools and features, but fortunately, it is not necessary to read the entire User Manual before you can use VirtualBox.
You can ﬁnd a summary of VirtualBox’s capabilities in chapter 1.3, Features overview, page 12.
For existing VirtualBox users who just want to see what’s new in this release, there is a detailed list in chapter 15, Change log, page 251.

10

1 First steps

1.1 Why is virtualization useful?
The techniques and features that VirtualBox provides are useful for several scenarios:
• Running multiple operating systems simultaneously. VirtualBox allows you to run more than one operating system at a time. This way, you can run software written for one operating system on another (for example, Windows software on Linux or a Mac) without having to reboot to use it. Since you can conﬁgure what kinds of “virtual” hardware should be presented to each such operating system, you can install an old operating system such as DOS or OS/2 even if your real computer’s hardware is no longer supported by that operating system.
• Easier software installations. Software vendors can use virtual machines to ship entire software conﬁgurations. For example, installing a complete mail server solution on a real machine can be a tedious task. With VirtualBox, such a complex setup (then often called an “appliance”) can be packed into a virtual machine. Installing and running a mail server becomes as easy as importing such an appliance into VirtualBox.
• Testing and disaster recovery. Once installed, a virtual machine and its virtual hard disks can be considered a “container” that can be arbitrarily frozen, woken up, copied, backed up, and transported between hosts.
On top of that, with the use of another VirtualBox feature called “snapshots”, one can save a particular state of a virtual machine and revert back to that state, if necessary. This way, one can freely experiment with a computing environment. If something goes wrong (e.g. after installing misbehaving software or infecting the guest with a virus), one can easily switch back to a previous snapshot and avoid the need of frequent backups and restores.
Any number of snapshots can be created, allowing you to travel back and forward in virtual machine time. You can delete snapshots while a VM is running to reclaim disk space.
• Infrastructure consolidation. Virtualization can signiﬁcantly reduce hardware and electricity costs. Most of the time, computers today only use a fraction of their potential power and run with low average system loads. A lot of hardware resources as well as electricity is thereby wasted. So, instead of running many such physical computers that are only partially used, one can pack many virtual machines onto a few powerful hosts and balance the loads between them.

1.2 Some terminology
When dealing with virtualization (and also for understanding the following chapters of this documentation), it helps to acquaint oneself with a bit of crucial terminology, especially the following terms:
Host operating system (host OS). This is the operating system of the physical computer on which VirtualBox was installed. There are versions of VirtualBox for Windows, Mac OS
X, Linux and Solaris hosts; for details, please see chapter 1.4, Supported host operating systems, page 14.
Most of the time, this User Manual discusses all VirtualBox versions together. There may be platform-speciﬁc differences which we will point out where appropriate.
Guest operating system (guest OS). This is the operating system that is running inside the virtual machine. Theoretically, VirtualBox can run any x86 operating system (DOS, Windows, OS/2, FreeBSD, OpenBSD), but to achieve near-native performance of the guest code on your machine, we had to go through a lot of optimizations that are speciﬁc to certain operating systems. So while your favorite operating system may run as a guest, we

11

1 First steps ofﬁcially support and optimize for a select few (which, however, include the most common ones). See chapter 3.1, Supported guest operating systems, page 43 for details.
Virtual machine (VM). This is the special environment that VirtualBox creates for your guest operating system while it is running. In other words, you run your guest operating system
“in” a VM. Normally, a VM will be shown as a window on your computer’s desktop, but depending on which of the various frontends of VirtualBox you use, it can be displayed in full screen mode or remotely on another computer.
In a more abstract way, internally, VirtualBox thinks of a VM as a set of parameters that determine its behavior. They include hardware settings (how much memory the VM should have, what hard disks VirtualBox should virtualize through which container ﬁles, what CDs are mounted etc.) as well as state information (whether the VM is currently running, saved, its snapshots etc.). These settings are mirrored in the VirtualBox Manager window as well as the VBoxManage command line program; see chapter 8, VBoxManage, page 115. In other words, a VM is also what you can see in its settings dialog.
Guest Additions. This refers to special software packages which are shipped with VirtualBox but designed to be installed inside a VM to improve performance of the guest OS and to add extra features. This is described in detail in chapter 4, Guest Additions, page 59.

1.3 Features overview
Here’s a brief outline of VirtualBox’s main features:
• Portability. VirtualBox runs on a large number of 32-bit and 64-bit host operating systems
(again, see chapter 1.4, Supported host operating systems, page 14 for details).
VirtualBox is a so-called “hosted” hypervisor (sometimes referred to as a “type 2” hypervisor). Whereas a “bare-metal” or “type 1” hypervisor would run directly on the hardware,
VirtualBox requires an existing operating system to be installed. It can thus run alongside existing applications on that host.
To a very large degree, VirtualBox is functionally identical on all of the host platforms, and the same ﬁle and image formats are used. This allows you to run virtual machines created on one host on another host with a different host operating system; for example, you can create a virtual machine on Windows and then run it under Linux.
In addition, virtual machines can easily be imported and exported using the Open Virtualization Format (OVF, see chapter 1.14, Importing and exporting virtual machines, page 30), an industry standard created for this purpose. You can even import OVFs that were created with a different virtualization software.
• No hardware virtualization required. For many scenarios, VirtualBox does not require the processor features built into newer hardware like Intel VT-x or AMD-V. As opposed to many other virtualization solutions, you can therefore use VirtualBox even on older hardware where these features are not present. The technical details are explained in chapter 10.3, Hardware vs. software virtualization, page 219.
• Guest Additions: shared folders, seamless windows, 3D virtualization. The VirtualBox
Guest Additions are software packages which can be installed inside of supported guest systems to improve their performance and to provide additional integration and communication with the host system. After installing the Guest Additions, a virtual machine will support automatic adjustment of video resolutions, seamless windows, accelerated 3D graphics and more. The Guest Additions are described in detail in chapter 4, Guest Additions, page
59.

12

1 First steps
In particular, Guest Additions provide for “shared folders”, which let you access ﬁles from the host system from within a guest machine. Shared folders are described in chapter 4.3,
Shared folders, page 69.
• Great hardware support. Among others, VirtualBox supports:
– Guest multiprocessing (SMP). VirtualBox can present up to 32 virtual CPUs to each virtual machine, irrespective of how many CPU cores are physically present on your host. – USB device support. VirtualBox implements a virtual USB controller and allows you to connect arbitrary USB devices to your virtual machines without having to install device-speciﬁc drivers on the host. USB support is not limited to certain device categories. For details, see chapter 3.10.1, USB settings, page 55.
– Hardware compatibility. VirtualBox virtualizes a vast array of virtual devices, among them many devices that are typically provided by other virtualization platforms. That includes IDE, SCSI and SATA hard disk controllers, several virtual network cards and sound cards, virtual serial and parallel ports and an Input/Output Advanced Programmable Interrupt Controller (I/O APIC), which is found in many modern PC systems. This eases cloning of PC images from real machines and importing of third-party virtual machines into VirtualBox.
– Full ACPI support. The Advanced Conﬁguration and Power Interface (ACPI) is fully supported by VirtualBox. This eases cloning of PC images from real machines or thirdparty virtual machines into VirtualBox. With its unique ACPI power status support,
VirtualBox can even report to ACPI-aware guest operating systems the power status of the host. For mobile systems running on battery, the guest can thus enable energy saving and notify the user of the remaining power (e.g. in full screen modes).
– Multiscreen resolutions. VirtualBox virtual machines support screen resolutions many times that of a physical screen, allowing them to be spread over a large number of screens attached to the host system.
– Built-in iSCSI support. This unique feature allows you to connect a virtual machine directly to an iSCSI storage server without going through the host system. The VM accesses the iSCSI target directly without the extra overhead that is required for virtualizing hard disks in container ﬁles. For details, see chapter 5.10, iSCSI servers, page
92.
– PXE Network boot. The integrated virtual network cards of VirtualBox fully support remote booting via the Preboot Execution Environment (PXE).
• Multigeneration branched snapshots. VirtualBox can save arbitrary snapshots of the state of the virtual machine. You can go back in time and revert the virtual machine to any such snapshot and start an alternative VM conﬁguration from there, effectively creating a whole snapshot tree. For details, see chapter 1.10, Snapshots, page 25. You can create and delete snapshots while the virtual machine is running.
• VM groups. VirtualBox provides a groups feature that enables the user to organize and control virtual machines collectively, as well as individually. In addition to basic groups, it is also possible for any VM to be in more than one group, and for groups to be nested in a hierarchy – i.e. groups of groups. In general, the operations that can be performed on groups are the same as those that can be applied to individual VMs i.e. Start, Pause, Reset,
Close (Save state, Send Shutdown, Poweroff), Discard Saved State, Show in ﬁleSystem,
Sort.
• Clean architecture; unprecedented modularity. VirtualBox has an extremely modular design with well-deﬁned internal programming interfaces and a clean separation of client and server code. This makes it easy to control it from several interfaces at once: for

13

1 First steps example, you can start a VM simply by clicking on a button in the VirtualBox graphical user interface and then control that machine from the command line, or even remotely.
See chapter 1.16, Alternative front-ends, page 31 for details.
Due to its modular architecture, VirtualBox can also expose its full functionality and conﬁgurability through a comprehensive software development kit (SDK), which allows for integrating every aspect of VirtualBox with other software systems. Please see chapter 11,
VirtualBox programming interfaces, page 225 for details.
• Remote machine display. The VirtualBox Remote Desktop Extension (VRDE) allows for high-performance remote access to any running virtual machine. This extension supports the Remote Desktop Protocol (RDP) originally built into Microsoft Windows, with special additions for full client USB support.
The VRDE does not rely on the RDP server that is built into Microsoft Windows; instead, it is plugged directly into the virtualization layer. As a result, it works with guest operating systems other than Windows (even in text mode) and does not require application support in the virtual machine either. The VRDE is described in detail in chapter 7.1, Remote display
(VRDP support), page 105.
On top of this special capacity, VirtualBox offers you more unique features:
– Extensible RDP authentication. VirtualBox already supports Winlogon on Windows and PAM on Linux for RDP authentication. In addition, it includes an easy-to-use SDK which allows you to create arbitrary interfaces for other methods of authentication; see chapter 7.1.5, RDP authentication, page 109 for details.
– USB over RDP. Via RDP virtual channel support, VirtualBox also allows you to connect arbitrary USB devices locally to a virtual machine which is running remotely on a
VirtualBox RDP server; see chapter 7.1.4, Remote USB, page 109 for details.

1.4 Supported host operating systems
Currently, VirtualBox runs on the following host operating systems:
• Windows hosts:
– Windows Vista SP1 and later (32-bit and 64-bit1 ).
– Windows Server 2008 (64-bit)
– Windows Server 2008 R2 (64-bit)
– Windows 7 (32-bit and 64-bit)
– Windows 8 (32-bit and 64-bit)
– Windows 8.1 (32-bit and 64-bit)
– Windows Server 2012 (64-bit)
– Windows Server 2012 R2 (64-bit)
• Mac OS X hosts (64-bit):2
– 10.8 (Mountain Lion)
– 10.9 (Mavericks)
– 10.10 (Yosemite)
1 Support

for 64-bit Windows was added with VirtualBox 1.5.
Mac OS X support (beta stage) was added with VirtualBox 1.4, full support with 1.6. Mac OS X 10.4
(Tiger) support was removed with VirtualBox 3.1. Mac OS X 10.7 (Lion) and earlier was removed with VirtualBox
5.0.

2 Preliminary

14

1 First steps
Intel hardware is required; please see chapter 14, Known limitations, page 247 also.
• Linux hosts (32-bit and 64-bit3 ). Among others, this includes:
– Ubuntu 10.04 to 15.04
– Debian GNU/Linux 6.0 (“Squeeze”) and 8.0 (“Jessie”)
– Oracle Enterprise Linux 5, Oracle Linux 6 and 7
– Redhat Enterprise Linux 5, 6 and 7
– Fedora Core / Fedora 6 to 22
– Gentoo Linux
– openSUSE 11.4, 12.1, 12.2, 13.1
– Mandriva 2011
It should be possible to use VirtualBox on most systems based on Linux kernel 2.6 or
3.x using either the VirtualBox installer or by doing a manual installation; see chapter
2.3, Installing on Linux hosts, page 35. However, the formally tested and supported Linux distributions are those for which we offer a dedicated package.
Note that starting with VirtualBox 2.1, Linux 2.4-based host operating systems are no longer supported.
• Solaris hosts (64-bit only) are supported with the restrictions listed in chapter 14, Known limitations, page 247:
– Solaris 11
– Solaris 10 (U10 and higher)
Note that the above list is informal. Oracle support for customers who have a support contract is limited to a subset of the listed host operating systems. Also, any feature which is marked as experimental is not supported. Feedback and suggestions about such features are welcome.

1.5 Installing VirtualBox and extension packs
VirtualBox comes in many different packages, and installation depends on your host operating system. If you have installed software before, installation should be straightforward: on each host platform, VirtualBox uses the installation method that is most common and easy to use. If you run into trouble or have special requirements, please refer to chapter 2, Installation details, page 33 for details about the various installation methods.
Starting with version 4.0, VirtualBox is split into several components.
1. The base package consists of all open-source components and is licensed under the GNU
General Public License V2.
2. Additional extension packs can be downloaded which extend the functionality of the
VirtualBox base package. Currently, Oracle provides the one extension pack, which can be found at http://www.virtualbox.org and provides the following added functionality:
a) The virtual USB 2.0 (EHCI) device; see chapter 3.10.1, USB settings, page 55.
b) The virtual USB 3.0 (xHCI) device; see chapter 3.10.1, USB settings, page 55.
c) VirtualBox Remote Desktop Protocol (VRDP) support; see chapter 7.1, Remote display
(VRDP support), page 105.
3 Support

for 64-bit Linux was added with VirtualBox 1.4.

15

1 First steps
d) Host webcam passthrough; see chapter chapter 9.7.1, Using a host webcam in the guest, page 181.
e) Intel PXE boot ROM.
f) Experimental support for PCI passthrough on Linux hosts; see chapter 9.6, PCI passthrough, page 180.
VirtualBox extension packages have a .vbox-extpack ﬁle name extension. To install an extension, simply double-click on the package ﬁle and a Network Operations Manager window will appear, guiding you through the required steps.
To view the extension packs that are currently installed, please start the VirtualBox Manager (see the next section). From the “File” menu, please select “Preferences”. In the window that shows up, go to the “Extensions” category which shows you the extensions which are currently installed and allows you to remove a package or add a new one.
Alternatively you can use VBoxManage on the command line: see chapter 8.36, VBoxManage extpack, page 169 for details.

1.6 Starting VirtualBox
After installation, you can start VirtualBox as follows:
• On a Windows host, in the standard “Programs” menu, click on the item in the “VirtualBox” group. On Vista or Windows 7, you can also type “VirtualBox” in the search box of the
“Start” menu.
• On a Mac OS X host, in the Finder, double-click on the “VirtualBox” item in the “Applications” folder. (You may want to drag this item onto your Dock.)
• On a Linux or Solaris host, depending on your desktop environment, a “VirtualBox” item may have been placed in either the “System” or “System Tools” group of your “Applications” menu. Alternatively, you can type VirtualBox in a terminal.
When you start VirtualBox for the ﬁrst time, a window like the following should come up:

This window is called the “VirtualBox Manager”. On the left, you can see a pane that will later list all your virtual machines. Since you have not created any, the list is empty. A row of buttons

16

1 First steps above it allows you to create new VMs and work on existing VMs, once you have some. The pane on the right displays the properties of the virtual machine currently selected, if any. Again, since you don’t have any machines yet, the pane displays a welcome message.
To give you an idea what VirtualBox might look like later, after you have created many machines, here’s another example:

1.7 Creating your ﬁrst virtual machine
Click on the “New” button at the top of the VirtualBox Manager window. A wizard will pop up to guide you through setting up a new virtual machine (VM):

On the following pages, the wizard will ask you for the bare minimum of information that is needed to create a VM, in particular:
1. The VM name will later be shown in the VM list of the VirtualBox Manager window, and it will be used for the VM’s ﬁles on disk. Even though any name could be used, keep in mind that once you have created a few VMs, you will appreciate if you have given your
VMs rather informative names; “My VM” would thus be less useful than “Windows XP SP2 with OpenOfﬁce”.

17

1 First steps
2. For “Operating System Type”, select the operating system that you want to install later.
The supported operating systems are grouped; if you want to install something very unusual that is not listed, select “Other”. Depending on your selection, VirtualBox will enable or disable certain VM settings that your guest operating system may require. This is particularly important for 64-bit guests (see chapter 3.1.2, 64-bit guests, page 44). It is therefore recommended to always set it to the correct value.
3. On the next page, select the memory (RAM) that VirtualBox should allocate every time the virtual machine is started. The amount of memory given here will be taken away from your host machine and presented to the guest operating system, which will report this size as the (virtual) computer’s installed RAM.
Note: Choose this setting carefully! The memory you give to the VM will not be available to your host OS while the VM is running, so do not specify more than you can spare. For example, if your host machine has 1 GB of RAM and you enter 512 MB as the amount of RAM for a particular virtual machine, while that VM is running, you will only have 512 MB left for all the other software on your host. If you run two VMs at the same time, even more memory will be allocated for the second VM (which may not even be able to start if that memory is not available). On the other hand, you should specify as much as your guest OS (and your applications) will require to run properly.
A Windows XP guest will require at least a few hundred MB RAM to run properly, and
Windows Vista will even refuse to install with less than 512 MB. Of course, if you want to run graphics-intensive applications in your VM, you may require even more RAM.
So, as a rule of thumb, if you have 1 GB of RAM or more in your host computer, it is usually safe to allocate 512 MB to each VM. But, in any case, make sure you always have at least
256 to 512 MB of RAM left on your host operating system. Otherwise you may cause your host OS to excessively swap out memory to your hard disk, effectively bringing your host system to a standstill.
As with the other settings, you can change this setting later, after you have created the VM.
4. Next, you must specify a virtual hard disk for your VM.
There are many and potentially complicated ways in which VirtualBox can provide hard disk space to a VM (see chapter 5, Virtual storage, page 81 for details), but the most common way is to use a large image ﬁle on your “real” hard disk, whose contents VirtualBox presents to your VM as if it were a complete hard disk. This ﬁle represents an entire hard disk then, so you can even copy it to another host and use it with another VirtualBox installation. The wizard shows you the following window:

18

1 First steps

Here you have the following options:
• To create a new, empty virtual hard disk, press the “New” button.
• You can pick an existing disk image ﬁle.
The drop-down list presented in the window contains all disk images which are currently remembered by VirtualBox, probably because they are currently attached to a virtual machine (or have been in the past).
Alternatively, you can click on the small folder button next to the drop-down list to bring up a standard ﬁle dialog, which allows you to pick any disk image ﬁle on your host disk.
Most probably, if you are using VirtualBox for the ﬁrst time, you will want to create a new disk image. Hence, press the “New” button.
This brings up another window, the “Create New Virtual Disk Wizard”, which helps you create a new disk image ﬁle in the new virtual machine’s folder.
VirtualBox supports two types of image ﬁles:
• A dynamically allocated ﬁle will only grow in size when the guest actually stores data on its virtual hard disk. It will therefore initially be small on the host hard drive and only later grow to the size speciﬁed as it is ﬁlled with data.
• A ﬁxed-size ﬁle will immediately occupy the ﬁle speciﬁed, even if only a fraction of the virtual hard disk space is actually in use. While occupying much more space, a ﬁxed-size ﬁle incurs less overhead and is therefore slightly faster than a dynamically allocated ﬁle.
For details about the differences, please refer to chapter 5.2, Disk image ﬁles (VDI, VMDK,
VHD, HDD), page 84.
To prevent your physical hard disk from running full, VirtualBox limits the size of the image ﬁle. Still, it needs to be large enough to hold the contents of your operating system and the applications you want to install – for a modern Windows or Linux guest, you will probably need several gigabytes for any serious use. The limit of the image ﬁle size can be changed later (see chapter 8.23, VBoxManage modifyhd, page 148 for details).

19

1 First steps

After having selected or created your image ﬁle, again press “Next” to go to the next page.
5. After clicking on “Finish”, your new virtual machine will be created. You will then see it in the list on the left side of the Manager window, with the name you entered initially.

Note: After becoming familiar with the use of wizards, consider using the Expert Mode available in some wizards. Where available, this is selectable using a button, and speeds up user processes using wizards.

1.8 Running your virtual machine
To start a virtual machine, you have several options:
• Double-click on its entry in the list within the Manager window or
• select its entry in the list in the Manager window it and press the “Start” button at the top or • for virtual machines created with VirtualBox 4.0 or later, navigate to the “VirtualBox VMs” folder in your system user’s home directory, ﬁnd the subdirectory of the machine you want to start and double-click on the machine settings ﬁle (with a .vbox ﬁle extension).
This opens up a new window, and the virtual machine which you selected will boot up. Everything which would normally be seen on the virtual system’s monitor is shown in the window, as can be seen with the image in chapter 1.2, Some terminology, page 11.
In general, you can use the virtual machine much like you would use a real computer. There are couple of points worth mentioning however.

1.8.1 Starting a new VM for the ﬁrst time
When a VM gets started for the ﬁrst time, another wizard – the “First Start Wizard” – will pop up to help you select an installation medium. Since the VM is created empty, it would otherwise behave just like a real computer with no operating system installed: it will do nothing and display an error message that no bootable operating system was found.
For this reason, the wizard helps you select a medium to install an operating system from.

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1 First steps
• If you have physical CD or DVD media from which you want to install your guest operating system (e.g. in the case of a Windows installation CD or DVD), put the media into your host’s CD or DVD drive.
Then, in the wizard’s drop-down list of installation media, select “Host drive” with the correct drive letter (or, in the case of a Linux host, device ﬁle). This will allow your VM to access the media in your host drive, and you can proceed to install from there.
• If you have downloaded installation media from the Internet in the form of an ISO image ﬁle (most probably in the case of a Linux distribution), you would normally burn this ﬁle to an empty CD or DVD and proceed as just described. With VirtualBox however, you can skip this step and mount the ISO ﬁle directly. VirtualBox will then present this ﬁle as a CD or DVD-ROM drive to the virtual machine, much like it does with virtual hard disk images.
For this case, the wizard’s drop-down list contains a list of installation media that were previously used with VirtualBox.
If your medium is not in the list (especially if you are using VirtualBox for the ﬁrst time), select the small folder icon next to the drop-down list to bring up a standard ﬁle dialog, with which you can pick the image ﬁle on your host disks.
In both cases, after making the choices in the wizard, you will be able to install your operating system. 1.8.2 Capturing and releasing keyboard and mouse
As of version 3.2, VirtualBox provides a virtual USB tablet device to new virtual machines through which mouse events are communicated to the guest operating system. As a result, if you are running a modern guest operating system that can handle such devices, mouse support may work out of the box without the mouse being “captured” as described below; see chapter 3.4.1,
“Motherboard” tab, page 47 for more information.
Otherwise, if the virtual machine only sees standard PS/2 mouse and keyboard devices, since the operating system in the virtual machine does not “know” that it is not running on a real computer, it expects to have exclusive control over your keyboard and mouse. This is, however, not the case since, unless you are running the VM in full screen mode, your VM needs to share keyboard and mouse with other applications and possibly other VMs on your host.
As a result, initially after installing a guest operating system and before you install the Guest
Additions (we will explain this in a minute), only one of the two – your VM or the rest of your computer – can “own” the keyboard and the mouse. You will see a second mouse pointer which will always be conﬁned to the limits of the VM window. Basically, you activate the VM by clicking inside it.
To return ownership of keyboard and mouse to your host operating system, VirtualBox reserves a special key on your keyboard for itself: the “host key”. By default, this is the right Control key on your keyboard; on a Mac host, the default host key is the left Command key. You can change this default in the VirtualBox Global Settings, see chapter 1.15, Global Settings, page 31.
In any case, the current setting for the host key is always displayed at the bottom right of your
VM window, should you have forgotten about it:

In detail, all this translates into the following:

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1 First steps
• Your keyboard is owned by the VM if the VM window on your host desktop has the keyboard focus (and then, if you have many windows open in your guest operating system as well, the window that has the focus in your VM). This means that if you want to type within your VM, click on the title bar of your VM window ﬁrst.
To release keyboard ownership, press the Host key (as explained above, typically the right
Control key).
Note that while the VM owns the keyboard, some key sequences (like Alt-Tab for example) will no longer be seen by the host, but will go to the guest instead. After you press the host key to re-enable the host keyboard, all key presses will go through the host again, so that sequences like Alt-Tab will no longer reach the guest. For technical reasons it may not be possible for the VM to get all keyboard input even when it does own the keyboard.
Examples of this are the Ctrl-Alt-Del sequence on Windows hosts or single keys grabbed by other applications on X11 hosts like the GNOME desktop’s “Control key highlights mouse pointer” functionality.
• Your mouse is owned by the VM only after you have clicked in the VM window. The host mouse pointer will disappear, and your mouse will drive the guest’s pointer instead of your normal mouse pointer.
Note that mouse ownership is independent of that of the keyboard: even after you have clicked on a titlebar to be able to type into the VM window, your mouse is not necessarily owned by the VM yet.
To release ownership of your mouse by the VM, also press the Host key.
As this behavior can be inconvenient, VirtualBox provides a set of tools and device drivers for guest systems called the “VirtualBox Guest Additions” which make VM keyboard and mouse operation a lot more seamless. Most importantly, the Additions will get rid of the second “guest” mouse pointer and make your host mouse pointer work directly in the guest.
This will be described later in chapter 4, Guest Additions, page 59.

1.8.3 Typing special characters
Operating systems expect certain key combinations to initiate certain procedures. Some of these key combinations may be difﬁcult to enter into a virtual machine, as there are three candidates as to who receives keyboard input: the host operating system, VirtualBox, or the guest operating system. Who of these three receives keypresses depends on a number of factors, including the key itself.
• Host operating systems reserve certain key combinations for themselves. For example, it is impossible to enter the Ctrl+Alt+Delete combination if you want to reboot the guest operating system in your virtual machine, because this key combination is usually hardwired into the host OS (both Windows and Linux intercept this), and pressing this key combination will therefore reboot your host.
Also, on Linux and Solaris hosts, which use the X Window System, the key combination
Ctrl+Alt+Backspace normally resets the X server (to restart the entire graphical user interface in case it got stuck). As the X server intercepts this combination, pressing it will usually restart your host graphical user interface (and kill all running programs, including
VirtualBox, in the process).
Third, on Linux hosts supporting virtual terminals, the key combination Ctrl+Alt+Fx
(where Fx is one of the function keys from F1 to F12) normally allows to switch between virtual terminals. As with Ctrl+Alt+Delete, these combinations are intercepted by the host operating system and therefore always switch terminals on the host.
If, instead, you want to send these key combinations to the guest operating system in the virtual machine, you will need to use one of the following methods:

22

1 First steps
– Use the items in the “Machine” menu of the virtual machine window. There you will ﬁnd “Insert Ctrl+Alt+Delete” and “Ctrl+Alt+Backspace”; the latter will only have an effect with Linux or Solaris guests, however.
– Press special key combinations with the Host key (normally the right Control key), which VirtualBox will then translate for the virtual machine:
∗ Host key + Del to send Ctrl+Alt+Del (to reboot the guest);
∗ Host key + Backspace to send Ctrl+Alt+Backspace (to restart the graphical user interface of a Linux or Solaris guest);
∗ Host key + F1 (or other function keys) to simulate Ctrl+Alt+F1 (or other function keys, i.e. to switch between virtual terminals in a Linux guest).
• For some other keyboard combinations such as Alt-Tab (to switch between open windows),
VirtualBox allows you to conﬁgure whether these combinations will affect the host or the guest, if a virtual machine currently has the focus. This is a global setting for all virtual machines and can be found under “File” -> “Preferences” -> “Input” -> “Auto-capture keyboard”. 1.8.4 Changing removable media
While a virtual machine is running, you can change removable media in the “Devices” menu of the VM’s window. Here you can select in detail what VirtualBox presents to your VM as a CD,
DVD, or ﬂoppy.
The settings are the same as would be available for the VM in the “Settings” dialog of the
VirtualBox main window, but since that dialog is disabled while the VM is in the “running” or
“saved” state, this extra menu saves you from having to shut down and restart the VM every time you want to change media.
Hence, in the “Devices” menu, VirtualBox allows you to attach the host drive to the guest or select a ﬂoppy or DVD image using the Disk Image Manager, all as described in chapter 1.11,
Virtual machine conﬁguration, page 28.

1.8.5 Resizing the machine’s window
You can resize the virtual machine’s window when it is running. In that case, one of three things will happen:
1. If you have “scale mode” enabled, then the virtual machine’s screen will be scaled to the size of the window. This can be useful if you have many machines running and want to have a look at one of them while it is running in the background. Alternatively, it might be useful to enlarge a window if the VM’s output screen is very small, for example because you are running an old operating system in it.
To enable scale mode, press the host key + C, or select “Scale mode” from the “Machine” menu in the VM window. To leave scale mode, press the host key + C again.
The aspect ratio of the guest screen is preserved when resizing the window. To ignore the aspect ratio, press Shift during the resize operation.
Please see chapter 14, Known limitations, page 247 for additional remarks.
2. If you have the Guest Additions installed and they support automatic resizing, the Guest
Additions will automatically adjust the screen resolution of the guest operating system. For example, if you are running a Windows guest with a resolution of 1024x768 pixels and you then resize the VM window to make it 100 pixels wider, the Guest Additions will change the Windows display resolution to 1124x768.
Please see chapter 4, Guest Additions, page 59 for more information about the Guest Additions.

23

1 First steps
3. Otherwise, if the window is bigger than the VM’s screen, the screen will be centered. If it is smaller, then scroll bars will be added to the machine window.

1.8.6 Saving the state of the machine
When you click on the “Close” button of your virtual machine window (at the top right of the window, just like you would close any other window on your system), VirtualBox asks you whether you want to “save” or “power off” the VM. (As a shortcut, you can also press the Host key together with “Q”.)

The difference between these three options is crucial. They mean:
• Save the machine state: With this option, VirtualBox “freezes” the virtual machine by completely saving its state to your local disk.
When you start the VM again later, you will ﬁnd that the VM continues exactly where it was left off. All your programs will still be open, and your computer resumes operation.
Saving the state of a virtual machine is thus in some ways similar to suspending a laptop computer (e.g. by closing its lid).
• Send the shutdown signal. This will send an ACPI shutdown signal to the virtual machine, which has the same effect as if you had pressed the power button on a real computer. So long as the VM is running a fairly modern operating system, this should trigger a proper shutdown mechanism from within the VM.
• Power off the machine: With this option, VirtualBox also stops running the virtual machine, but without saving its state.
Warning: This is equivalent to pulling the power plug on a real computer without shutting it down properly. If you start the machine again after powering it off, your operating system will have to reboot completely and may begin a lengthy check of its (virtual) system disks. As a result, this should not normally be done, since it can potentially cause data loss or an inconsistent state of the guest system on disk.
As an exception, if your virtual machine has any snapshots (see the next chapter), you can use this option to quickly restore the current snapshot of the virtual machine. In that case, powering off the machine will not disrupt its state, but any changes made since that snapshot was taken will be lost.
The “Discard” button in the VirtualBox Manager window discards a virtual machine’s saved state. This has the same effect as powering it off, and the same warnings apply.

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1 First steps

1.9 Using VM groups
VM groups enable the user to create ad hoc groups of VMs, and to manage and perform functions on them collectively, as well as individually. There are a number of features relating to groups:
1. Create a group using GUI option 1) Drag one VM on top of another VM.
Create a group using GUI option 2) Select multiple VMs and select “Group” on the right click menu, as follows:

2. Command line option 1) Create a group and assign a VM:
VBoxManage modifyvm "Fred" --groups "/TestGroup"

creates a group “TestGroup” and attaches the VM “Fred” to that group.
Command line option 2) Detach a VM from the group, and delete the group if empty:
VBoxManage modifyvm "Fred" --groups ""

It detaches all groups from the VM “Fred” and deletes the empty group.
3. Multiple groups e.g.:
VBoxManage modifyvm "Fred" --groups "/TestGroup,/TestGroup2"

It creates the groups “TestGroup” and “TestGroup2” (if they don’t exist yet) and attaches the VM “Fred” to both of them.
4. Nested groups – hierarchy of groups e.g.:
VBoxManage modifyvm "Fred" --groups "/TestGroup/TestGroup2"

It attaches the VM “Fred” to the subgroup “TestGroup2” of the “TestGroup” group.
5. Summary of group commands: Start, Pause, Reset, Close (save state, send shutdown signal, poweroff), Discard Saved State, Show in File System, Sort.

1.10 Snapshots
With snapshots, you can save a particular state of a virtual machine for later use. At any later time, you can revert to that state, even though you may have changed the VM considerably since then. A snapshot of a virtual machine is thus similar to a machine in “saved” state, as described above, but there can be many of them, and these saved states are preserved.

25

1 First steps
You can see the snapshots of a virtual machine by ﬁrst selecting a machine in the VirtualBox
Manager and then clicking on the “Snapshots” button at the top right. Until you take a snapshot of the machine, the list of snapshots will be empty except for the “Current state” item, which represents the “Now” point in the lifetime of the virtual machine.

1.10.1 Taking, restoring and deleting snapshots
There are three operations related to snapshots:
1. You can take a snapshot. This makes a copy of the machine’s current state, to which you can go back at any given time later.
• If your VM is currently running, select “Take snapshot” from the “Machine” pull-down menu of the VM window.
• If your VM is currently in either the “saved” or the “powered off” state (as displayed next to the VM in the VirtualBox main window), click on the “Snapshots” tab on the top right of the main window, and then
– either on the small camera icon (for “Take snapshot”) or
– right-click on the “Current State” item in the list and select “Take snapshot” from the menu.
In any case, a window will pop up and ask you for a snapshot name. This name is purely for reference purposes to help you remember the state of the snapshot. For example, a useful name would be “Fresh installation from scratch, no Guest Additions”, or “Service
Pack 3 just installed”. You can also add a longer text in the “Description” ﬁeld if you want.
Your new snapshot will then appear in the snapshots list. Underneath your new snapshot, you will see an item called “Current state”, signifying that the current state of your VM is a variation based on the snapshot you took earlier. If you later take another snapshot, you will see that they will be displayed in sequence, and each subsequent snapshot is derived from an earlier one:

26

1 First steps
VirtualBox imposes no limits on the number of snapshots you can take. The only practical limitation is disk space on your host: each snapshot stores the state of the virtual machine and thus occupies some disk space. (See the next section for details on what exactly is stored in a snapshot.)
2. You can restore a snapshot by right-clicking on any snapshot you have taken in the list of snapshots. By restoring a snapshot, you go back (or forward) in time: the current state of the machine is lost, and the machine is restored to the exact state it was in when the snapshot was taken.4
Note: Restoring a snapshot will affect the virtual hard drives that are connected to your
VM, as the entire state of the virtual hard drive will be reverted as well. This means also that all ﬁles that have been created since the snapshot and all other ﬁle changes will be lost. In order to prevent such data loss while still making use of the snapshot feature, it is possible to add a second hard drive in “write-through” mode using the VBoxManage interface and use it to store your data. As write-through hard drives are not included in snapshots, they remain unaltered when a machine is reverted. See chapter 5.4, Special image write modes, page 86 for details.
To avoid losing the current state when restoring a snapshot, you can create a new snapshot before the restore.
By restoring an earlier snapshot and taking more snapshots from there, it is even possible to create a kind of alternate reality and to switch between these different histories of the virtual machine. This can result in a whole tree of virtual machine snapshots, as shown in the screenshot above.
3. You can also delete a snapshot, which will not affect the state of the virtual machine, but only release the ﬁles on disk that VirtualBox used to store the snapshot data, thus freeing disk space. To delete a snapshot, right-click on it in the snapshots tree and select “Delete”.
As of VirtualBox 3.2, snapshots can be deleted even while a machine is running.
Note: Whereas taking and restoring snapshots are fairly quick operations, deleting a snapshot can take a considerable amount of time since large amounts of data may need to be copied between several disk image ﬁles. Temporary disk ﬁles may also need large amounts of disk space while the operation is in progress.
There are some situations which cannot be handled while a VM is running, and you will get an appropriate message that you need to perform this snapshot deletion when the VM is shut down.

1.10.2 Snapshot contents
Think of a snapshot as a point in time that you have preserved. More formally, a snapshot consists of three things:
• It contains a complete copy of the VM settings, including the hardware conﬁguration, so that when you restore a snapshot, the VM settings are restored as well. (For example, if
4 Both the terminology and the functionality of restoring snapshots has changed with VirtualBox 3.1.

Before that version, it was only possible to go back to the very last snapshot taken – not earlier ones, and the operation was called “Discard current state” instead of “Restore last snapshot”. The limitation has been lifted with version 3.1. It is now possible to restore any snapshot, going backward and forward in time.

27

1 First steps you changed the hard disk conﬁguration or the VM’s system settings, that change is undone when you restore the snapshot.)
The copy of the settings is stored in the machine conﬁguration, an XML text ﬁle, and thus occupies very little space.
• The complete state of all the virtual disks attached to the machine is preserved. Going back to a snapshot means that all changes that had been made to the machine’s disks – ﬁle by ﬁle, bit by bit – will be undone as well. Files that were since created will disappear, ﬁles that were deleted will be restored, changes to ﬁles will be reverted.
(Strictly speaking, this is only true for virtual hard disks in “normal” mode. As mentioned above, you can conﬁgure disks to behave differently with snapshots; see chapter 5.4, Special image write modes, page 86. Even more formally and technically correct, it is not the virtual disk itself that is restored when a snapshot is restored. Instead, when a snapshot is taken,
VirtualBox creates differencing images which contain only the changes since the snapshot were taken, and when the snapshot is restored, VirtualBox throws away that differencing image, thus going back to the previous state. This is both faster and uses less disk space.
For the details, which can be complex, please see chapter 5.5, Differencing images, page
88.)
Creating the differencing image as such does not occupy much space on the host disk initially, since the differencing image will initially be empty (and grow dynamically later with each write operation to the disk). The longer you use the machine after having created the snapshot, however, the more the differencing image will grow in size.
• Finally, if you took a snapshot while the machine was running, the memory state of the machine is also saved in the snapshot (the same way the memory can be saved when you close the VM window). When you restore such a snapshot, execution resumes at exactly the point when the snapshot was taken.
The memory state ﬁle can be as large as the memory size of the virtual machine and will therefore occupy quite some disk space as well.

1.11 Virtual machine conﬁguration
When you select a virtual machine from the list in the Manager window, you will see a summary of that machine’s settings on the right.
Clicking on the “Settings” button in the toolbar at the top brings up a detailed window where you can conﬁgure many of the properties of the selected VM. But be careful: even though it is possible to change all VM settings after installing a guest operating system, certain changes might prevent a guest operating system from functioning correctly if done after installation.
Note: The “Settings” button is disabled while a VM is either in the “running” or “saved” state. This is simply because the settings dialog allows you to change fundamental characteristics of the virtual computer that is created for your guest operating system, and this operating system may not take it well when, for example, half of its memory is taken away from under its feet. As a result, if the “Settings” button is disabled, shut down the current VM ﬁrst.
VirtualBox provides a plethora of parameters that can be changed for a virtual machine. The various settings that can be changed in the “Settings” window are described in detail in chapter
3, Conﬁguring virtual machines, page 43. Even more parameters are available with the VirtualBox command line interface; see chapter 8, VBoxManage, page 115.

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1 First steps

1.12 Removing virtual machines
To remove a virtual machine which you no longer need, right-click on it in the Manager’s VM list select “Remove” from the context menu that comes up.
A conﬁrmation window will come up that allows you to select whether the machine should only be removed from the list of machines or whether the ﬁles associated with it should also be deleted. The “Remove” menu item is disabled while a machine is running.

1.13 Cloning virtual machines
To experiment with a VM conﬁguration, test different guest OS levels or to simply backup a VM,
VirtualBox can create a full or a linked copy of an existing VM.5
A wizard will guide you through the clone process:

This wizard can be invoked from the context menu of the Manager’s VM list (select “Clone”) or the “Snapshots” view of the selected VM. First choose a new name for the clone. When you select
Reinitialize the MAC address of all network cards every network card get a new MAC address assigned. This is useful when both, the source VM and the cloned VM, have to operate on the same network. If you leave this unchanged, all network cards have the same MAC address like the one in the source VM. Depending on how you invoke the wizard you have different choices for the cloning operation. First you need to decide if the clone should be linked to the source VM or a fully independent clone should be created:
• Full clone: In this mode all depending disk images are copied to the new VM folder. The clone can fully operate without the source VM.
• Linked clone: In this mode new differencing disk images are created where the parent disk images are the source disk images. If you selected the current state of the source VM as clone point, a new snapshot will be created implicitly.
After selecting the clone mode, you need to decide about what exactly should be cloned. You can always create a clone of the current state only or all. When you select all, the current state and in addition all snapshots are cloned. Have you started from a snapshot which has additional children, you can also clone the current state and all children. This creates a clone starting with this snapshot and includes all child snaphots.
The clone operation itself can be a lengthy operation depending on the size and count of the attached disk images. Also keep in mind that every snapshot has differencing disk images attached, which need to be cloned as well.
The “Clone” menu item is disabled while a machine is running.
For how to clone a VM at the command line, please see chapter 8.9, VBoxManage clonevm, page 137.
5 Cloning

support was introduced with VirtualBox 4.1.

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1 First steps

1.14 Importing and exporting virtual machines
VirtualBox can import and export virtual machines in the industry-standard Open Virtualization
Format (OVF).6
OVF is a cross-platform standard supported by many virtualization products which allows for creating ready-made virtual machines that can then be imported into a virtualizer such as
VirtualBox. VirtualBox makes OVF import and export easy to access and supports it from the
Manager window as well as its command-line interface. This allows for packaging so-called virtual appliances: disk images together with conﬁguration settings that can be distributed easily. This way one can offer complete ready-to-use software packages (operating systems with applications) that need no conﬁguration or installation except for importing into VirtualBox.
Note: The OVF standard is complex, and support in VirtualBox is an ongoing process.
In particular, no guarantee is made that VirtualBox supports all appliances created by other virtualization software. For a list of known limitations, please see chapter 14,
Known limitations, page 247.
Appliances in OVF format can appear in two variants:
1. They can come in several ﬁles, as one or several disk images, typically in the widely-used
VMDK format (see chapter 5.2, Disk image ﬁles (VDI, VMDK, VHD, HDD), page 84) and a textual description ﬁle in an XML dialect with an .ovf extension. These ﬁles must then reside in the same directory for VirtualBox to be able to import them.
2. Alternatively, the above ﬁles can be packed together into a single archive ﬁle, typically with an .ova extension. (Such archive ﬁles use a variant of the TAR archive format and can therefore be unpacked outside of VirtualBox with any utility that can unpack standard
TAR ﬁles.)
To import an appliance in one of the above formats, simply double-click on the OVF/OVA ﬁle.7
Alternatively, select “File” -> “Import appliance” from the Manager window. In the ﬁle dialog that comes up, navigate to the ﬁle with either the .ovf or the .ova ﬁle extension.
If VirtualBox can handle the ﬁle, a dialog similar to the following will appear:

6 OVF

support was originally introduced with VirtualBox 2.2 and has seen major improvements with every version since. with version 4.0, VirtualBox creates ﬁle type associations for OVF and OVA ﬁles on your host operating system.

7 Starting

30

1 First steps
This presents the virtual machines described in the OVF ﬁle and allows you to change the virtual machine settings by double-clicking on the description items. Once you click on “Import”,
VirtualBox will copy the disk images and create local virtual machines with the settings described in the dialog. These will then show up in the Manager’s list of virtual machines.
Note that since disk images tend to be big, and VMDK images that come with virtual appliances are typically shipped in a special compressed format that is unsuitable for being used by virtual machines directly, the images will need to be unpacked and copied ﬁrst, which can take a few minutes. For how to import an image at the command line, please see chapter 8.10, VBoxManage import, page 138.
Conversely, to export virtual machines that you already have in VirtualBox, select “File” ->
“Export appliance”. A different dialog window shows up that allows you to combine several virtual machines into an OVF appliance. Then, select the target location where the target ﬁles should be stored, and the conversion process begins. This can again take a while.
For how to export an image at the command line, please see chapter 8.11, VBoxManage export, page 139.
Note: OVF cannot describe snapshots that were taken for a virtual machine. As a result, when you export a virtual machine that has snapshots, only the current state of the machine will be exported, and the disk images in the export will have a “ﬂattened” state identical to the current state of the virtual machine.

1.15 Global Settings
The global settings dialog can be reached through the File menu, selecting the Preferences... item. It offers a selection of settings which apply to all virtual machines of the current user or in the case of Extensions to the entire system:
1. General Enables the user to specify the default folder/directory for VM ﬁles, and the VRDP
Authentication Library.
2. Input Enables the user to specify the Host Key. It identiﬁes the key that toggles whether the cursor is in the focus of the VM or the Host operating system windows (see chapter 1.8.2,
Capturing and releasing keyboard and mouse, page 21) and which is also used to trigger certain VM actions (see chapter 1.8.3, Typing special characters, page 22)
3. Update Enables the user to specify various settings for Automatic Updates.
4. Language Enables the user to specify the GUI language.
5. Display Enables the user to specify the screen resolution, and its width and height.
6. Network Enables the user to conﬁgure the details of Host Only Networks.
7. Extensions Enables the user to list and manage the installed extension packages.
8. Proxy Enables the user to conﬁgure a HTTP Proxy Server.

1.16 Alternative front-ends
As brieﬂy mentioned in chapter 1.3, Features overview, page 12, VirtualBox has a very ﬂexible internal design that allows for using multiple interfaces to control the same virtual machines. To illustrate, you can, for example, start a virtual machine with the VirtualBox Manager window

31

1 First steps and then stop it from the command line. With VirtualBox’s support for the Remote Desktop
Protocol (RDP), you can even run virtual machines remotely on a headless server and have all the graphical output redirected over the network.
In detail, the following front-ends are shipped in the standard VirtualBox package:
1. VirtualBox is the VirtualBox Manager. This graphical user interface uses the Qt toolkit; most of this User Manual is dedicated to describing it. While this is the easiest to use, some of the more advanced VirtualBox features are kept away from it to keep it simple.
2. VBoxManage is our command-line interface for automated and very detailed control of every aspect of VirtualBox. It is described in chapter 8, VBoxManage, page 115.
3. VBoxSDL is an alternative, simple graphical front-end with an intentionally limited feature set, designed to only display virtual machines that are controlled in detail with
VBoxManage. This is interesting for business environments where displaying all the bells and whistles of the full GUI is not feasible. VBoxSDL is described in chapter 9.1, VBoxSDL, the simpliﬁed VM displayer, page 171.
4. Finally, VBoxHeadless is yet another front-end that produces no visible output on the host at all, but can act as a RDP server if the VirtualBox Remote Desktop Extension (VRDE) is installed and enabled for the VM. As opposed to the other graphical interfaces, the headless front-end requires no graphics support. This is useful, for example, if you want to host your virtual machines on a headless Linux server that has no X Window system installed. For details, see chapter 7.1.2, VBoxHeadless, the remote desktop server, page 106.
If the above front-ends still do not satisfy your particular needs, it is possible to create yet another front-end to the complex virtualization engine that is the core of VirtualBox, as the VirtualBox core neatly exposes all of its features in a clean API; please refer to chapter 11, VirtualBox programming interfaces, page 225.

32

2 Installation details
As installation of VirtualBox varies depending on your host operating system, we provide installation instructions in four separate chapters for Windows, Mac OS X, Linux and Solaris, respectively.

2.1 Installing on Windows hosts
2.1.1 Prerequisites
For the various versions of Windows that we support as host operating systems, please refer to chapter 1.4, Supported host operating systems, page 14.
In addition, Windows Installer 1.1 or higher must be present on your system. This should be the case if you have all recent Windows updates installed.

2.1.2 Performing the installation
The VirtualBox installation can be started
• either by double-clicking on its executable ﬁle (contains both 32- and 64-bit architectures)
• or by entering
VirtualBox.exe -extract

on the command line. This will extract both installers into a temporary directory in which you’ll then ﬁnd the usual .MSI ﬁles. Then you can do a msiexec /i VirtualBox-<version>-MultiArch_<x86|amd64>.msi

to perform the installation.
In either case, this will display the installation welcome dialog and allow you to choose where to install VirtualBox to and which components to install. In addition to the VirtualBox application, the following components are available:
USB support This package contains special drivers for your Windows host that VirtualBox requires to fully support USB devices inside your virtual machines.
Networking This package contains extra networking drivers for your Windows host that
VirtualBox needs to support Bridged Networking (to make your VM’s virtual network cards accessible from other machines on your physical network).
Python Support This package contains Python scripting support for the VirtualBox API (see chapter 11, VirtualBox programming interfaces, page 225). For this to work, an already working Windows Python installation on the system is required.1
Depending on your Windows conﬁguration, you may see warnings about “unsigned drivers” or similar. Please select “Continue” on these warnings as otherwise VirtualBox might not function correctly after installation.
1 See,

for example, http://www.python.org/download/windows/.

33

2 Installation details
The installer will create a “VirtualBox” group in the Windows “Start” menu which allows you to launch the application and access its documentation.
With standard settings, VirtualBox will be installed for all users on the local system. In case this is not wanted, you have to invoke the installer by ﬁrst extracting it by using
VirtualBox.exe -extract

and then do as follows:
VirtualBox.exe -msiparams ALLUSERS=2

or msiexec /i VirtualBox-<version>-MultiArch_<x86|amd64>.msi ALLUSERS=2

on the extracted .MSI ﬁles. This will install VirtualBox only for the current user.
If you do not want to install all features of VirtualBox, you can set the optional ADDLOCAL parameter to explicitly name the features to be installed. The following features are available:
VBoxApplication Main binaries of VirtualBox.
Note: This feature must not be absent since it contains the minimum set of ﬁles to have working VirtualBox installation.

VBoxUSB USB support.
VBoxNetwork All networking support; includes the VBoxNetworkFlt and VBoxNetworkAdp features (see below).
VBoxNetworkFlt Bridged networking support.
VBoxNetworkAdp Host-only networking support.
VBoxPython Python support.
For example, to only install USB support along with the main binaries, do a:
VirtualBox.exe -msiparams ADDLOCAL=VBoxApplication,VBoxUSB

or msiexec /i VirtualBox-<version>-MultiArch_<x86|amd64>.msi ADDLOCAL=VBoxApplication,VBoxUSB

The user is able to choose between NDIS5 and NDIS6 host network ﬁlters drivers during the installation. This is realized via a command line parameter NETWORKTYPE. The NDIS6 driver is default for Windows Vista and later. For older Windows versions, the installer will automatically select the NDIS5 driver and this cannot be changed. For Windows Vista and later the user can force to install the (legacy) NDIS5 host network ﬁlter driver using NETWORKTYPE=NDIS5. For example, to install the NDIS5 driver on Windows 7, do
VirtualBox.exe -msiparams NETWORKTYPE=NDIS5

or msiexec /i VirtualBox-<version>-MultiArch_<x86|amd64>.msi NETWORKTYPE=NDIS5

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2 Installation details

2.1.3 Uninstallation
As VirtualBox uses the standard Microsoft Windows installer, VirtualBox can be safely uninstalled at any time by choosing the program entry in the “Add/Remove Programs” applet in the Windows
Control Panel.

2.1.4 Unattended installation
Unattended installations can be performed using the standard MSI support.

2.2 Installing on Mac OS X hosts
2.2.1 Performing the installation
For Mac OS X hosts, VirtualBox ships in a disk image (dmg) ﬁle. Perform the following steps:
1. Double-click on that ﬁle to have its contents mounted.
2. A window will open telling you to double click on the VirtualBox.mpkg installer ﬁle displayed in that window.
3. This will start the installer, which will allow you to select where to install VirtualBox to.
After installation, you can ﬁnd a VirtualBox icon in the “Applications” folder in the Finder.

2.2.2 Uninstallation
To uninstall VirtualBox, open the disk image (dmg) ﬁle again and double-click on the uninstall icon contained therein.

2.2.3 Unattended installation
To perform a non-interactive installation of VirtualBox you can use the command line version of the installer application.
Mount the disk image (dmg) ﬁle as described in the normal installation or use the following command line: hdiutil attach /path/to/VirtualBox-xyz.dmg

Then open a terminal session and execute: sudo installer -pkg /Volumes/VirtualBox/VirtualBox.pkg -target /Volumes/Macintosh\ HD

2.3 Installing on Linux hosts
2.3.1 Prerequisites
For the various versions of Linux that we support as host operating systems, please refer to chapter 1.4, Supported host operating systems, page 14.
You will need to install the following packages on your Linux system before starting the installation (some systems will do this for you automatically when you install VirtualBox):
• Qt 4.8.0 or higher;
• SDL 1.2.7 or higher (this graphics library is typically called libsdl or similar).

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2 Installation details
Note: To be precise, these packages are only required if you want to run the VirtualBox graphical user interfaces. In particular, VirtualBox, the graphical VirtualBox manager, requires both Qt and SDL; VBoxSDL, our simpliﬁed GUI, requires only SDL. By contrast, if you only want to run VBoxHeadless, neither Qt nor SDL are required.

2.3.2 The VirtualBox kernel module
VirtualBox uses a special kernel module called vboxdrv to perform physical memory allocation and to gain control of the processor for guest system execution. Without this kernel module, you can still use the VirtualBox manager to conﬁgure virtual machines, but they will not start. In addition, there are the network kernel modules vboxnetflt and vboxnetadp which are required for the more advanced networking features of VirtualBox.
The VirtualBox kernel module is automatically installed on your system when you install
VirtualBox. To maintain it with future kernel updates, for those Linux distributions which provide it – most current ones – we recommend installing Dynamic Kernel Module Support (DKMS)2 .
This framework helps with building and upgrading kernel modules.
If DKMS is not already installed, execute one of the following:
• On an Ubuntu system: sudo apt-get install dkms

• On a Fedora system: yum install dkms

• On a Mandriva or Mageia system: urpmi dkms

If DKMS is available and installed, the VirtualBox kernel module should always work automatically, and it will be automatically rebuilt if your host kernel is updated.
Otherwise, there are only two situations in which you will need to worry about the kernel module: 1. The original installation fails. This probably means that your Linux system is not prepared for building external kernel modules.
Most Linux distributions can be set up simply by installing the right packages - normally, these will be the GNU compiler (GCC), GNU Make (make) and packages containing header ﬁles for your kernel - and making sure that all system updates are installed and that the system is running the most up-to-date kernel included in the distribution. The version numbers of the header ﬁle packages must be the same as that of the kernel you are using.
• With Debian and Ubuntu releases, you must install the right version of the linux-headers and if it exists the linux-kbuild package. Current Ubuntu releases should have the right packages installed by default.
• In even older Debian and Ubuntu releases, you must install the right version of the kernel-headers package.
• On Fedora and Redhat systems, the package is kernel-devel.
• On SUSE and openSUSE Linux, you must install the right versions of the kernel-source and kernel-syms packages.

2 See http://en.wikipedia.org/wiki/Dynamic_Kernel_Module_Support

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for an introduction.

2 Installation details
• If you have built your own kernel, you will need to make sure that you also installed all the required header and other ﬁles for building external modules to the right locations. The details of how to do this will depend on how you built your kernel, and if you are unsure you should consult the documentation which you followed to do so.
2. The kernel of your Linux host was updated and DKMS is not installed. In that case, the kernel module will need to be reinstalled by executing (as root): rcvboxdrv setup

2.3.3 Performing the installation
VirtualBox is available in a number of package formats native to various common Linux distributions (see chapter 1.4, Supported host operating systems, page 14 for details). In addition, there is an alternative generic installer (.run) which should work on most Linux distributions.
2.3.3.1 Installing VirtualBox from a Debian/Ubuntu package
First, download the appropriate package for your distribution. The following examples assume that you are installing to a 32-bit Ubuntu Raring system. Use dpkg to install the Debian package: sudo dpkg -i virtualbox-5.0_5.0.0_Ubuntu_raring_i386.deb

You will be asked to accept the VirtualBox Personal Use and Evaluation License. Unless you answer “yes” here, the installation will be aborted.
The installer will also search for a VirtualBox kernel module suitable for your kernel. The package includes pre-compiled modules for the most common kernel conﬁgurations. If no suitable kernel module is found, the installation script tries to build a module itself. If the build process is not successful you will be shown a warning and the package will be left unconﬁgured. Please have a look at /var/log/vbox-install.log to ﬁnd out why the compilation failed. You may have to install the appropriate Linux kernel headers (see chapter 2.3.2, The VirtualBox kernel module, page 36). After correcting any problems, do sudo rcvboxdrv setup

This will start a second attempt to build the module.
If a suitable kernel module was found in the package or the module was successfully built, the installation script will attempt to load that module. If this fails, please see chapter 12.8.1, Linux kernel module refuses to load, page 239 for further information.
Once VirtualBox has been successfully installed and conﬁgured, you can start it by selecting
“VirtualBox” in your start menu or from the command line (see chapter 2.3.5, Starting VirtualBox on Linux, page 40).
2.3.3.2 Using the alternative installer (VirtualBox.run)
The alternative installer performs the following steps:
• It unpacks the application ﬁles to the target directory,
/opt/VirtualBox/

which cannot be changed.
• It builds the VirtualBox kernel modules (vboxdrv, vboxnetflt and vboxnetadp) and installs them.
• It creates /etc/init.d/vboxdrv, an init script to start the VirtualBox kernel module.
• It creates a new system group called vboxusers.

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2 Installation details
• It creates symbolic links in /usr/bin to the a shell script (/opt/VirtualBox/VBox) which does some sanity checks and dispatches to the actual executables, VirtualBox, VBoxSDL,
VBoxVRDP, VBoxHeadless and VBoxManage
• It creates /etc/udev/rules.d/60-vboxdrv.rules, a description ﬁle for udev, if that is present, which makes the USB devices accessible to all users in the vboxusers group.
• It writes the installation directory to /etc/vbox/vbox.cfg.
The installer must be executed as root with either install or uninstall as the ﬁrst parameter. sudo ./VirtualBox.run install

Or if you do not have the “sudo” command available, run the following as root instead:
./VirtualBox.run install

After that you need to put every user which should be able to access USB devices from
VirtualBox guests in the group vboxusers, either through the GUI user management tools or by running the following command as root: sudo usermod -a -G vboxusers username

Note: The usermod command of some older Linux distributions does not support the
-a option (which adds the user to the given group without affecting membership of other groups). In this case, ﬁnd out the current group memberships with the groups command and add all these groups in a comma-separated list to the command line after the -G option, e.g. like this: usermod -G group1,group2,vboxusers username.

2.3.3.3 Performing a manual installation
If, for any reason, you cannot use the shell script installer described previously, you can also perform a manual installation. Invoke the installer like this:
./VirtualBox.run --keep --noexec

This will unpack all the ﬁles needed for installation in the directory install under the current directory. The VirtualBox application ﬁles are contained in VirtualBox.tar.bz2 which you can unpack to any directory on your system. For example: sudo mkdir /opt/VirtualBox sudo tar jxf ./install/VirtualBox.tar.bz2 -C /opt/VirtualBox

or as root: mkdir /opt/VirtualBox tar jxf ./install/VirtualBox.tar.bz2 -C /opt/VirtualBox

The sources for VirtualBox’s kernel module are provided in the src directory. To build the module, change to the directory and issue make If everything builds correctly, issue the following command to install the module to the appropriate module directory: sudo make install

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In case you do not have sudo, switch the user account to root and perform make install

The VirtualBox kernel module needs a device node to operate. The above make command will tell you how to create the device node, depending on your Linux system. The procedure is slightly different for a classical Linux setup with a /dev directory, a system with the now deprecated devfs and a modern Linux system with udev.
On certain Linux distributions, you might experience difﬁculties building the module. You will have to analyze the error messages from the build system to diagnose the cause of the problems.
In general, make sure that the correct Linux kernel sources are used for the build process.
Note that the /dev/vboxdrv kernel module device node must be owned by root:root and must be read/writable only for the user.
Next, you will have to install the system initialization script for the kernel module: cp /opt/VirtualBox/vboxdrv.sh /etc/init.d/vboxdrv

(assuming you installed VirtualBox to the /opt/VirtualBox directory) and activate the initialization script using the right method for your distribution. You should create VirtualBox’s conﬁguration ﬁle: mkdir /etc/vbox echo INSTALL_DIR=/opt/VirtualBox > /etc/vbox/vbox.cfg

and, for convenience, create the following symbolic links: ln ln ln ln

-sf
-sf
-sf
-sf

/opt/VirtualBox/VBox.sh
/opt/VirtualBox/VBox.sh
/opt/VirtualBox/VBox.sh
/opt/VirtualBox/VBox.sh

/usr/bin/VirtualBox
/usr/bin/VBoxManage
/usr/bin/VBoxHeadless
/usr/bin/VBoxSDL

2.3.3.4 Updating and uninstalling VirtualBox
Before updating or uninstalling VirtualBox, you must terminate any virtual machines which are currently running and exit the VirtualBox or VBoxSVC applications. To update VirtualBox, simply run the installer of the updated version. To uninstall VirtualBox, invoke the installer like this: sudo ./VirtualBox.run uninstall

or as root
./VirtualBox.run uninstall

. Starting with version 2.2.2, you can uninstall the .run package by invoking
/opt/VirtualBox/uninstall.sh

To manually uninstall VirtualBox, simply undo the steps in the manual installation in reverse order. 2.3.3.5 Automatic installation of Debian packages
The Debian packages will request some user feedback when installed for the ﬁrst time. The debconf system is used to perform this task. To prevent any user interaction during installation, default values can be deﬁned. A ﬁle vboxconf can contain the following debconf settings: virtualbox virtualbox/module-compilation-allowed boolean true virtualbox virtualbox/delete-old-modules boolean true

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The ﬁrst line allows compilation of the vboxdrv kernel module if no module was found for the current kernel. The second line allows the package to delete any old vboxdrv kernel modules compiled by previous installations.
These default settings can be applied with debconf-set-selections vboxconf

prior to the installation of the VirtualBox Debian package.
In addition there are some common conﬁguration options that can be set prior to the installation, described in chapter 2.3.3.7, Automatic installation options, page 40.
2.3.3.6 Automatic installation of .rpm packages
The .rpm format does not provide a conﬁguration system comparable to the debconf system. See chapter 2.3.3.7, Automatic installation options, page 40 for how to set some common installation options provided by VirtualBox.
2.3.3.7 Automatic installation options
To conﬁgure the installation process of our .deb and .rpm packages, you can create a response ﬁle named /etc/default/virtualbox. The automatic generation of the udev rule can be prevented by the following setting:
INSTALL_NO_UDEV=1

The creation of the group vboxusers can be prevented by
INSTALL_NO_GROUP=1

If the line
INSTALL_NO_VBOXDRV=1

is speciﬁed, the package installer will not try to build the vboxdrv kernel module if no module ﬁtting the current kernel was found.

2.3.4 The vboxusers group
The Linux installers create the system user group vboxusers during installation. Any system user who is going to use USB devices from VirtualBox guests must be a member of that group. A user can be made a member of the group vboxusers through the GUI user/group management or at the command line with sudo usermod -a -G vboxusers username

2.3.5 Starting VirtualBox on Linux
The easiest way to start a VirtualBox program is by running the program of your choice
(VirtualBox, VBoxManage, VBoxSDL or VBoxHeadless) from a terminal. These are symbolic links to VBox.sh that start the required program for you.
The following detailed instructions should only be of interest if you wish to execute VirtualBox without installing it ﬁrst. You should start by compiling the vboxdrv kernel module (see above) and inserting it into the Linux kernel. VirtualBox consists of a service daemon (VBoxSVC) and several application programs. The daemon is automatically started if necessary. All VirtualBox applications will communicate with the daemon through Unix local domain sockets. There can be multiple daemon instances under different user accounts and applications can only communicate with the daemon running under the user account as the application. The local

40

2 Installation details domain socket resides in a subdirectory of your system’s directory for temporary ﬁles called
.vbox-<username>-ipc. In case of communication problems or server startup problems, you may try to remove this directory.
All VirtualBox applications (VirtualBox, VBoxSDL, VBoxManage and VBoxHeadless) require the VirtualBox directory to be in the library path:
LD_LIBRARY_PATH=. ./VBoxManage showvminfo "Windows XP"

2.4 Installing on Solaris hosts
For the speciﬁc versions of Solaris that we support as host operating systems, please refer to chapter 1.4, Supported host operating systems, page 14.
If you have a previously installed instance of VirtualBox on your Solaris host, please uninstall it ﬁrst before installing a new instance. Refer to chapter 2.4.4, Uninstallation, page 42 for uninstall instructions. 2.4.1 Performing the installation
VirtualBox is available as a standard Solaris package. Download the VirtualBox SunOS package which includes the 64-bit versions of VirtualBox. The installation must be performed as root and from the global zone as the VirtualBox installer loads kernel drivers which cannot be done from non-global zones. To verify which zone you are currently in, execute the zonename command.
Execute the following commands: gunzip -cd VirtualBox-5.0.0-SunOS.tar.gz | tar xvf -

Starting with VirtualBox 3.1 the VirtualBox kernel package is no longer a separate package and has been integrated into the main package. Install the VirtualBox package using: pkgadd -d VirtualBox-5.0.0-SunOS.pkg

Note: If you are using Solaris Zones, to install VirtualBox only into the current zone and not into any other zone, use pkgadd -G. For more information refer to the pkgadd manual; see also chapter 2.4.6, Conﬁguring a zone for running VirtualBox, page 42.
The installer will then prompt you to enter the package you wish to install. Choose “1” or
“all” and proceed. Next the installer will ask you if you want to allow the postinstall script to be executed. Choose “y” and proceed as it is essential to execute this script which installs the
VirtualBox kernel module. Following this conﬁrmation the installer will install VirtualBox and execute the postinstall setup script.
Once the postinstall script has been executed your installation is now complete. You may now safely delete the uncompressed package and autoresponse ﬁles from your system. VirtualBox would be installed in /opt/VirtualBox.

2.4.2 The vboxuser group
Starting with VirtualBox 4.1, the installer creates the system user group vboxuser during installation for Solaris hosts that support the USB features required by VirtualBox. Any system user who is going to use USB devices from VirtualBox guests must be a member of this group. A user can be made a member of this group through the GUI user/group management or at the command line by executing as root: usermod -G vboxuser username

Note that adding an active user to that group will require that user to log out and back in again. This should be done manually after successful installation of the package.

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2.4.3 Starting VirtualBox on Solaris
The easiest way to start a VirtualBox program is by running the program of your choice
(VirtualBox, VBoxManage, VBoxSDL or VBoxHeadless) from a terminal. These are symbolic links to VBox.sh that start the required program for you.
Alternatively, you can directly invoke the required programs from /opt/VirtualBox. Using the links provided is easier as you do not have to type the full path.
You can conﬁgure some elements of the VirtualBox Qt GUI such as fonts and colours by executing VBoxQtconfig from the terminal.

2.4.4 Uninstallation
Uninstallation of VirtualBox on Solaris requires root permissions. To perform the uninstallation, start a root terminal session and execute: pkgrm SUNWvbox

After conﬁrmation, this will remove VirtualBox from your system.
If you are uninstalling VirtualBox version 3.0 or lower, you need to remove the VirtualBox kernel interface package, execute: pkgrm SUNWvboxkern

2.4.5 Unattended installation
To perform a non-interactive installation of VirtualBox we have provided a response ﬁle named autoresponse that the installer will use for responses to inputs rather than ask them from you.
Extract the tar.gz package as described in the normal installation. Then open a root terminal session and execute: pkgadd -d VirtualBox-5.0.0-SunOS-x86 -n -a autoresponse SUNWvbox

To perform a non-interactive uninstallation, open a root terminal session and execute: pkgrm -n -a /opt/VirtualBox/autoresponse SUNWvbox

2.4.6 Conﬁguring a zone for running VirtualBox
Assuming that VirtualBox has already been installed into your zone, you need to give the zone access to VirtualBox’s device node. This is done by performing the following steps. Start a root terminal and execute: zonecfg -z vboxzone

Replace “vboxzone” with the name of the zone in which you intend to run VirtualBox.
Inside the zonecfg prompt add the device resource and match properties to the zone. Here’s how it can be done: zonecfg:vboxzone>add device zonecfg:vboxzone:device>set match=/dev/vboxdrv zonecfg:vboxzone:device>end zonecfg:vboxzone>add device zonecfg:vboxzone:device>set match=/dev/vboxdrvu zonecfg:vboxzone:device>end zonecfg:vboxzone>exit

If you are running VirtualBox 2.2.0 or above on Solaris 11 or above, you may add a device for
/dev/vboxusbmon too, similar to what was shown above. This does not apply to Solaris 10 hosts

due to lack of USB support.
Next reboot the zone using zoneadm and you should be able to run VirtualBox from within the conﬁgured zone.

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3 Conﬁguring virtual machines
Whereas chapter 1, First steps, page 10 gave you a quick introduction to VirtualBox and how to get your ﬁrst virtual machine running, the following chapter describes in detail how to conﬁgure virtual machines.
You have considerable latitude in deciding what virtual hardware will be provided to the guest.
The virtual hardware can be used for communicating with the host system or with other guests.
For instance, if you provide VirtualBox with the image of a CD-ROM in an ISO ﬁle, VirtualBox can present this image to a guest system as if it were a physical CD-ROM. Similarly, you can give a guest system access to the real network via its virtual network card, and, if you so choose, give the host system, other guests, or computers on the Internet access to the guest system.

3.1 Supported guest operating systems
Since VirtualBox is designed to provide a generic virtualization environment for x86 systems, it may run operating systems of any kind, even those not listed here. However, the focus is to optimize VirtualBox for the following guest systems:
Windows NT 4.0 All versions, editions and service packs are fully supported; however, there are some issues with older service packs. We recommend to install service pack 6a. Guest
Additions are available with a limited feature set.
Windows 2000 / XP / Server 2003 / Vista / Server 2008 / Windows 7 / Windows 8 / Server 2012
All versions, editions and service packs are fully supported (including 64-bit versions, under the preconditions listed below). Guest Additions are available.
DOS / Windows 3.x / 95 / 98 / ME Limited testing has been performed. Use beyond legacy installation mechanisms not recommended. No Guest Additions available.
Linux 2.4 Limited support.
Linux 2.6 All versions/editions are fully supported (32 bits and 64 bits). Guest Additions are available. We strongly recommend using a Linux kernel version 2.6.13 or higher for better performance.
Note: Certain Linux kernel releases have bugs that prevent them from executing in a virtual environment; please see chapter 12.4.3, Buggy Linux 2.6 kernel versions, page
236 for details.

Linux 3.x All versions/editions are fully supported (32 bits and 64 bits). Guest Additions are available. Solaris 10 (u6 and higher), Solaris 11 (including Solaris 11 Express) Fully supported (64 bits, prior to Solaris 11 11/11 also 32 bits). Guest Additions are available.
FreeBSD Requires hardware virtualization to be enabled. Limited support. Guest Additions are not available yet.

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OpenBSD Requires hardware virtualization to be enabled. Versions 3.7 and later are supported.
Guest Additions are not available yet.
OS/2 Warp 4.5 Requires hardware virtualization to be enabled. We ofﬁcially support MCP2 only; other OS/2 versions may or may not work. Guest Additions are available with a limited feature set.1
Mac OS X VirtualBox 3.2 added experimental support for Mac OS X guests, but this comes with restrictions. Please see the following section as well as chapter 14, Known limitations, page
247.

3.1.1 Mac OS X guests
Starting with version 3.2, VirtualBox has experimental support for Mac OS X guests. This allows you to install and execute unmodiﬁed versions of Mac OS X on supported host hardware.
Whereas competing solutions perform modiﬁcations to the Mac OS X install DVDs (e.g. different boot loader and replaced ﬁles), VirtualBox is the ﬁrst product to provide the modern PC architecture expected by OS X without requiring any “hacks”.
You should be aware of a number of important issues before attempting to install a Mac OS
X guest:
1. Mac OS X is commercial, licensed software and contains both license and technical restrictions that limit its use to certain hardware and usage scenarios. It is important that you understand and obey these restrictions.
In particular, for most versions of Mac OS X, Apple prohibits installing them on non-Apple hardware. These license restrictions are also enforced on a technical level. Mac OS X veriﬁes whether it is running on Apple hardware, and most DVDs that that come with Apple hardware even check for an exact model. These restrictions are not circumvented by VirtualBox and continue to apply.
2. Only CPUs known and tested by Apple are supported. As a result, if your Intel CPU is newer than the build of Mac OS X, or if you have a non-Intel CPU, it will most likely panic during bootup with an “Unsupported CPU” exception. It is generally best to use the Mac
OS X DVD that came with your Apple hardware.
3. The Mac OS X installer expects the harddisk to be partitioned so when it does not offer a selection, you have to launch the Disk Utility from the “Tools” menu and partition the hard disk. Then close the Disk Utility and proceed with the installation.
4. In addition, as Mac OS X support in VirtualBox is currently still experimental, please refer also to chapter 14, Known limitations, page 247.

3.1.2 64-bit guests
VirtualBox supports 64-bit guest operating systems, even on 32-bit host operating systems,2 provided that the following conditions are met:
1. You need a 64-bit processor with hardware virtualization support (see chapter 10.3, Hardware vs. software virtualization, page 219).
2. You must enable hardware virtualization for the particular VM for which you want 64-bit support; software virtualization is not supported for 64-bit VMs.
1 See

chapter 14, Known limitations, page 247. guest support was added with VirtualBox 2.0; support for 64-bit guests on 32-bit hosts was added with
VirtualBox 2.1.

2 64-bit

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3 Conﬁguring virtual machines
3. If you want to use 64-bit guest support on a 32-bit host operating system, you must also select a 64-bit operating system for the particular VM. Since supporting 64 bits on 32bit hosts incurs additional overhead, VirtualBox only enables this support upon explicit request. On 64-bit hosts (which typically come with hardware virtualization support), 64-bit guest operating systems are always supported regardless of settings, so you can simply install a
64-bit operating system in the guest.

Warning: On any host, you should enable the I/O APIC for virtual machines that you intend to use in 64-bit mode. This is especially true for 64-bit Windows VMs.
See chapter 3.3.2, “Advanced” tab, page 46. In addition, for 64-bit Windows guests, you should make sure that the VM uses the Intel networking device, since there is no 64-bit driver support for the AMD PCNet card; see chapter 6.1, Virtual networking hardware, page 94.
If you use the “Create VM” wizard of the VirtualBox graphical user interface (see chapter
1.7, Creating your ﬁrst virtual machine, page 17), VirtualBox will automatically use the correct settings for each selected 64-bit operating system type.

3.2 Emulated hardware
VirtualBox virtualizes nearly all hardware of the host. Depending on a VM’s conﬁguration, the guest will see the following virtual hardware:
• Input devices. By default, VirtualBox emulates a standard PS/2 keyboard and mouse.
These devices are supported by almost all past and present operating systems.
In addition, VirtualBox can provide virtual USB input devices to avoid having to capture mouse and keyboard, as described in chapter 1.8.2, Capturing and releasing keyboard and mouse, page 21.
• Graphics. The VirtualBox graphics device (sometimes referred to as VGA device) is, unlike nearly all other emulated devices, not based on any physical counterpart. It is a simple, synthetic device which provides compatibility with standard VGA and several extended registers used by the VESA BIOS Extensions (VBE).
• Storage. VirtualBox currently emulates the standard ATA interface found on Intel
PIIX3/PIIX4 chips, the SATA (AHCI) interface, and two SCSI adapters (LSI Logic and BusLogic); see chapter 5.1, Hard disk controllers: IDE, SATA (AHCI), SCSI, SAS, USB MSC, page
81 for details. Whereas providing one of these would be enough for VirtualBox by itself, this multitude of storage adapters is required for compatibility with other hypervisors. Windows is particularly picky about its boot devices, and migrating VMs between hypervisors is very difﬁcult or impossible if the storage controllers are different.
• Networking. See chapter 6.1, Virtual networking hardware, page 94.
• USB. VirtualBox emulates three USB host controllers: xHCI, EHCI, and OHCI. While xHCI handles all USB transfer speeds, only guest operating systems released approximately after
2011 support xHCI. Note that for Windows 7 guests, 3rd party drivers must be installed for xHCI support.
Older operating systems typically support OHCI and EHCI. The two controllers are needed because OHCI only handles USB low- and full-speed devices (both USB 1.x and 2.0), while
EHCI only handles high-speed devices (USB 2.0 only).

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3 Conﬁguring virtual machines
The emulated USB controllers do not communicate directly with devices on the host but rather with a virtual USB layer which abstracts the USB protocol and allows the use of remote USB devices.
• Audio. See chapter 3.7, Audio settings, page 53.

3.3 General settings
In the Settings window, under “General”, you can conﬁgure the most fundamental aspects of the virtual machine such as memory and essential hardware. There are three tabs, “Basic”,
“Advanced” and “Description”.

3.3.1 “Basic” tab
Under the “Basic” tab of the “General” settings category, you can ﬁnd these settings:
Name The name under which the VM is shown in the list of VMs in the main window. Under this name, VirtualBox also saves the VM’s conﬁguration ﬁles. By changing the name, VirtualBox renames these ﬁles as well. As a result, you can only use characters which are allowed in your host operating system’s ﬁle names.
Note that internally, VirtualBox uses unique identiﬁers (UUIDs) to identify virtual machines. You can display these with VBoxManage.
Operating system / version The type of the guest operating system that is (or will be) installed in the VM. This is the same setting that was speciﬁed in the “New Virtual Machine” wizard, as described in chapter 1.7, Creating your ﬁrst virtual machine, page 17.
Whereas the default settings of a newly created VM depend on the selected operating system type, changing the type later has no effect on VM settings; this value is then purely informational and decorative.

3.3.2 “Advanced” tab
Snapshot Folder By default, VirtualBox saves snapshot data together with your other
VirtualBox conﬁguration data; see chapter 10.1, Where VirtualBox stores its ﬁles, page
215. With this setting, you can specify any other folder for each VM.
Shared Clipboard You can select here whether the clipboard of the guest operating system should be shared with that of your host. If you select “Bidirectional”, then VirtualBox will always make sure that both clipboards contain the same data. If you select “Host to guest” or “Guest to host”, then VirtualBox will only ever copy clipboard data in one direction.
Clipboard sharing requires that the VirtualBox Guest Additions be installed. As a result, this setting has no effect otherwise; see chapter 4, Guest Additions, page 59 for details.
The shared clipboard is disabled by default. See chapter 13.3.2.3, Clipboard, page 245 for an explanation. This setting can be changed at any time using the “Shared Clipboard” menu item in the “Devices” menu of the virtual machine.
Drag’n’Drop This setting allows to enable support for drag’n drop: Select an object (e.g. a ﬁle) from the host or guest and directly copy or open it on the guest or host. Multiple per-VM drag’n drop modes allow restricting access in either direction.
For drag’n drop to work the Guest Additions need to be installed on the guest.
Note: Drag’n drop is disabled by default. This setting can be changed at any time using the “Drag’n’Drop” menu item in the “Devices” menu of the virtual machine.

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3 Conﬁguring virtual machines
See chapter 4.4, Drag’n Drop, page 72 for more information.

3

Removable Media If this is checked, VirtualBox will save the state of what media has been mounted between several runs of a virtual machine.
Mini ToolBar In full screen or seamless mode, VirtualBox can display a small toolbar that contains some of the items that are normally available from the virtual machine’s menu bar.
This toolbar reduces itself to a small gray line unless you move the mouse over it. With the toolbar, you can return from full screen or seamless mode, control machine execution or enable certain devices. If you don’t want to see the toolbar, disable this setting.
The second setting allows to show the toolbar at the top of the screen instead of showing it at the bottom.

3.3.3 “Description” tab
Here you can enter any description for your virtual machine, if you want. This has no effect on the functionality of the machine, but you may ﬁnd this space useful to note down things like the conﬁguration of a virtual machine and the software that has been installed into it.
To insert a line break into the description text ﬁeld, press Shift+Enter.

3.4 System settings
The “System” category groups various settings that are related to the basic hardware that is presented to the virtual machine.
Note: As the activation mechanism of Microsoft Windows is sensitive to hardware changes, if you are changing hardware settings for a Windows guest, some of these changes may trigger a request for another activation with Microsoft.

3.4.1 “Motherboard” tab
On the “Motherboard” tab, you can inﬂuence virtual hardware that would normally be on the motherboard of a real computer.
Base memory This sets the amount of RAM that is allocated and given to the VM when it is running. The speciﬁed amount of memory will be requested from the host operating system, so it must be available or made available as free memory on the host when attempting to start the VM and will not be available to the host while the VM is running. This is the same setting that was speciﬁed in the “New Virtual Machine” wizard, as described with guidelines under chapter 1.7, Creating your ﬁrst virtual machine, page 17 above.
Generally, it is possible to change the memory size after installing the guest operating system (provided you do not reduce the memory to an amount where the operating system would no longer boot).
Boot order This setting determines the order in which the guest operating system will attempt to boot from the various virtual boot devices. Analogous to a real PC’s BIOS setting,
VirtualBox can tell a guest OS to start from the virtual ﬂoppy, the virtual CD/DVD drive, the virtual hard drive (each of these as deﬁned by the other VM settings), the network, or none of these.
3 Experimental

support for drag and drop was added with VirtualBox 4.2.

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3 Conﬁguring virtual machines
If you select “Network”, the VM will attempt to boot from a network via the PXE mechanism. This needs to be conﬁgured in detail on the command line; please see chapter 8.8,
VBoxManage modifyvm, page 129.
Chipset Here you can select which chipset will be presented to the virtual machine. Before
VirtualBox 4.0, PIIX3 was the only available option here. For modern guest operating systems such as Mac OS X, that old chipset is no longer well supported. As a result, VirtualBox
4.0 introduced an emulation of the more modern ICH9 chipset, which supports PCI express, three PCI buses, PCI-to-PCI bridges and Message Signaled Interrupts (MSI). This allows modern operating systems to address more PCI devices and no longer requires IRQ sharing. Using the ICH9 chipset it is also possible to conﬁgure up to 36 network cards (up to 8 network adapters with PIIX3). Note that the ICH9 support is experimental and not recommended for guest operating systems which do not require it.
Pointing Device The default virtual pointing devices for older guests is the traditional PS/2 mouse. If set to USB tablet, VirtualBox reports to the virtual machine that a USB tablet device is present and communicates mouse events to the virtual machine through this device. The third setting is a USB Multi-Touch Tablet which is suited for recent Windows guests. Using the virtual USB tablet has the advantage that movements are reported in absolute coordinates (instead of as relative position changes), which allows VirtualBox to translate mouse events over the VM window into tablet events without having to “capture” the mouse in the guest as described in chapter 1.8.2, Capturing and releasing keyboard and mouse, page 21. This makes using the VM less tedious even if Guest Additions are not installed.4 Enable I/O APIC Advanced Programmable Interrupt Controllers (APICs) are a newer x86 hardware feature that have replaced old-style Programmable Interrupt Controllers (PICs) in recent years. With an I/O APIC, operating systems can use more than 16 interrupt requests
(IRQs) and therefore avoid IRQ sharing for improved reliability.
Note: Enabling the I/O APIC is required for 64-bit guest operating systems, especially
Windows Vista; it is also required if you want to use more than one virtual CPU in a virtual machine.
However, software support for I/O APICs has been unreliable with some operating systems other than Windows. Also, the use of an I/O APIC slightly increases the overhead of virtualization and therefore slows down the guest OS a little.
Warning: All Windows operating systems starting with Windows 2000 install different kernels depending on whether an I/O APIC is available. As with ACPI, the I/O APIC therefore must not be turned off after installation of a Windows guest OS. Turning it on after installation will have no effect however.

Enable EFI This enables Extensible Firmware Interface (EFI), which replaces the legacy BIOS and may be useful for certain advanced use cases. Please refer to chapter 3.12, Alternative ﬁrmware (EFI), page 57 for details.

4 The

virtual USB tablet was added with VirtualBox 3.2. Depending on the guest operating system selected, this is now enabled by default for new virtual machines.

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3 Conﬁguring virtual machines
Hardware clock in UTC time If checked, VirtualBox will report the system time in UTC format to the guest instead of local (host) time. This affects how the virtual real-time clock (RTC) operates and may be useful for Unix-like guest operating systems, which typically expect the hardware clock to be set to UTC.
In addition, you can turn off the Advanced Conﬁguration and Power Interface (ACPI) which
VirtualBox presents to the guest operating system by default. ACPI is the current industry standard to allow operating systems to recognize hardware, conﬁgure motherboards and other devices and manage power. As all modern PCs contain this feature and Windows and Linux have been supporting it for years, it is also enabled by default in VirtualBox. It can only be turned off on the command line; see chapter 8.8, VBoxManage modifyvm, page 129.
Warning: All Windows operating systems starting with Windows 2000 install different kernels depending on whether ACPI is available, so ACPI must not be turned off after installation of a Windows guest OS. Turning it on after installation will have no effect however. 3.4.2 “Processor” tab
On the “Processor” tab, you can set how many virtual CPU cores the guest operating systems should see. Starting with version 3.0, VirtualBox supports symmetrical multiprocessing (SMP) and can present up to 32 virtual CPU cores to each virtual machine.
You should not, however, conﬁgure virtual machines to use more CPU cores than you have available physically (real cores, no hyperthreads).
On this tab you can also set the “CPU execution cap”. This setting limits the amount of time a host CPU spents to emulate a virtual CPU. The default setting is 100% meaning that there is no limitation. A setting of 50% implies a single virtual CPU can use up to 50% of a single host CPU.
Note that limiting the execution time of the virtual CPUs may induce guest timing problems.
In addition, the “Enable PAE/NX” setting determines whether the PAE and NX capabilities of the host CPU will be exposed to the virtual machine. PAE stands for “Physical Address Extension”.
Normally, if enabled and supported by the operating system, then even a 32-bit x86 CPU can access more than 4 GB of RAM. This is made possible by adding another 4 bits to memory addresses, so that with 36 bits, up to 64 GB can be addressed. Some operating systems (such as Ubuntu Server) require PAE support from the CPU and cannot be run in a virtual machine without it.
With virtual machines running modern server operating systems, VirtualBox also supports CPU hot-plugging. For details about this, please refer to chapter 9.5, CPU hot-plugging, page 179.

3.4.3 “Acceleration” tab
On this page, you can determine whether and how VirtualBox should use hardware virtualization extensions that your host CPU may support. This is the case with most CPUs built after 2006.
You can select for each virtual machine individually whether VirtualBox should use software or hardware virtualization.5
In most cases, the default settings will be ﬁne; VirtualBox will have picked sensible defaults depending on the operating system that you selected when you created the virtual machine. In certain situations, however, you may want to change these preconﬁgured defaults.
Advanced users may be interested in technical details about software vs. hardware virtualization; please see chapter 10.3, Hardware vs. software virtualization, page 219.
5 Prior

to VirtualBox version 2.2, software virtualization was the default; starting with version 2.2, VirtualBox will enable hardware virtualization by default for new virtual machines that you create. (Existing virtual machines are not automatically changed for compatibility reasons, and the default can of course be changed for each virtual machine.)

49

3 Conﬁguring virtual machines
If your host’s CPU supports the nested paging (AMD-V) or EPT (Intel VT-x) features, then you can expect a signiﬁcant performance increase by enabling nested paging in addition to hardware virtualization. For technical details, see chapter 10.7, Nested paging and VPIDs, page 224.
Starting with version 5.0, VirtualBox provides paravirtualization interfaces to improve timekeeping accuracy and performance of guest operating systems. The options available are documented under the paravirtprovider option in chapter 8.8, VBoxManage modifyvm, page 129.
For futher details on the paravirtualization providers, please refer to chapter 10.4, Paravirtualization providers, page 220.

3.5 Display settings
Video memory size This sets the size of the memory provided by the virtual graphics card available to the guest, in MB. As with the main memory, the speciﬁed amount will be allocated from the host’s resident memory. Based on the amount of video memory, higher resolutions and color depths may be available.
The GUI will show a warning if the amount of video memory is too small to be able to switch the VM into full screen mode. The minimum value depends on the number of virtual monitors, the screen resolution and the color depth of the host display as well as of the activation of 3D acceleration and 2D video acceleration. A rough estimate is (color depth / 8) x vertical pixels x horizontal pixels x number of screens = number of bytes. Like said above, there might be extra memory required for any activated display acceleration setting. Monitor count With this setting VirtualBox can provide more than one virtual monitor to a virtual machine. If a guest operating system (such as Windows) supports multiple attached monitors, VirtualBox can pretend that multiple virtual monitors are present.6 Up to 8 such virtual monitors are supported.
The output of the multiple monitors will be displayed on the host in multiple VM windows which are running side by side.
However, in full screen and seamless mode, they will use the available physical monitors attached to the host. As a result, for full screen and seamless modes to work with multiple monitors, you will need at least as many physical monitors as you have virtual monitors conﬁgured, or VirtualBox will report an error. You can conﬁgure the relationship between guest and host monitors using the view menu by pressing Host key + Home when you are in full screen or seamless mode.
Please see chapter 14, Known limitations, page 247 also.
Enable 3D acceleration If a virtual machine has Guest Additions installed, you can select here whether the guest should support accelerated 3D graphics. Please refer to chapter 4.5.1,
Hardware 3D acceleration (OpenGL and Direct3D 8/9), page 73 for details.
Enable 2D video acceleration If a virtual machine with Microsoft Windows has Guest Additions installed, you can select here whether the guest should support accelerated 2D video graphics. Please refer to chapter 4.5.2, Hardware 2D video acceleration for Windows guests, page 75 for details.
Remote display Under the “Remote display” tab, if the VirtualBox Remote Display Extension
(VRDE) is installed, you can enable the VRDP server that is built into VirtualBox. This allows you to connect to the console of the virtual machine remotely with any standard
RDP viewer, such as mstsc.exe that comes with Microsoft Windows. On Linux and Solaris systems you can use the standard open-source rdesktop program. These features are described in detail in chapter 7.1, Remote display (VRDP support), page 105.
6 Multiple

monitor support was added with VirtualBox 3.2.

50

3 Conﬁguring virtual machines
Video Capture Under the “Video Capture” tab you can enable video capturing for this VM. Note that this feature can also be enabled/disabled while the VM is executed.

3.6 Storage settings
The “Storage” category in the VM settings allows you to connect virtual hard disk, CD/DVD and ﬂoppy images and drives to your virtual machine.
In a real PC, so-called “storage controllers” connect physical disk drives to the rest of the computer. Similarly, VirtualBox presents virtual storage controllers to a virtual machine. Under each controller, the virtual devices (hard disks, CD/DVD or ﬂoppy drives) attached to the controller are shown.
Note: This section can only give you a quick introduction to the VirtualBox storage settings. Since VirtualBox gives you an enormous wealth of options in this area, we have dedicated an entire chapter of this User Manual to explaining all the details: please see chapter 5, Virtual storage, page 81.
If you have used the “Create VM” wizard to create a machine, you will normally see something like the following:

Depending on the guest operating system type that you selected when you created the VM, the typical layout of storage devices in a new VM is as follows:
• You will see an IDE controller, to which a virtual CD/DVD drive has been attached (to the
“secondary master” port of the IDE controller).
• You will also see a SATA controller, which is a more modern type of storage controller for higher hard disk data throughput, to which the virtual hard disks are attached. Initially you will normally have one such virtual disk, but as you can see in the above screenshot, you can have more than one, each represented by a disk image ﬁle (VDI ﬁles, in this case).

51

3 Conﬁguring virtual machines
If you created your VM with an older version of VirtualBox, the default storage layout may differ. You might then only have an IDE controller to which both the CD/DVD drive and the hard disks have been attached. This might also apply if you selected an older operating system type when you created the VM. Since older operating systems do not support SATA without additional drivers, VirtualBox will make sure that no such devices are present initially. Please see chapter 5.1, Hard disk controllers: IDE, SATA (AHCI), SCSI, SAS, USB MSC, page 81 for additional information. VirtualBox also provides a ﬂoppy controller, which is special: you cannot add devices other than ﬂoppy drives to it. Virtual ﬂoppy drives, like virtual CD/DVD drives, can be connected to either a host ﬂoppy drive (if you have one) or a disk image, which in this case must be in RAW format. You can modify these media attachments freely. For example, if you wish to copy some ﬁles from another virtual disk that you created, you can connect that disk as a second hard disk, as in the above screenshot. You could also add a second virtual CD/DVD drive, or change where these items are attached. The following options are available:
• To add another virtual hard disk, or a CD/DVD or ﬂoppy drive, select the storage controller to which it should be added (IDE, SATA, SCSI, SAS, ﬂoppy controller) and then click on the “add disk” button below the tree. You can then either select “Add CD/DVD device” or “Add Hard Disk”. (If you clicked on a ﬂoppy controller, you can add a ﬂoppy drive instead.) Alternatively, right-click on the storage controller and select a menu item there.
On the right part of the window, you can then set the following:
1. You can then select to which device slot of the controller the virtual disk should be connected to. IDE controllers have four slots which have traditionally been called
“primary master”, “primary slave”, “secondary master” and “secondary slave”. By contrast, SATA and SCSI controllers offer you up to 30 slots to which virtual devices can be attached.
2. You can select which image ﬁle to use.
– For virtual hard disks, a button with a drop-down list appears on the right, offering you to either select a virtual hard disk ﬁle using a standard ﬁle dialog or to create a new hard disk (image ﬁle), which will bring up the “Create new disk” wizard, which was described in chapter 1.7, Creating your ﬁrst virtual machine, page 17.
For details on the image ﬁle types that are supported, please see chapter 5.2, Disk image ﬁles (VDI, VMDK, VHD, HDD), page 84.
– For virtual CD/DVD drives, the image ﬁles will typically be in the standard ISO format instead. Most commonly, you will select this option when installing an operating system from an ISO ﬁle that you have obtained from the Internet. For example, most Linux distributions are available in this way.
For virtual CD/DVD drives, the following additional options are available:
∗ If you select “Host drive” from the list, then the physical device of the host computer is connected to the VM, so that the guest operating system can read from and write to your physical device. This is, for instance, useful if you want to install Windows from a real installation CD. In this case, select your host drive from the drop-down list presented.
If you want to write (burn) CDs or DVDs using the host drive, you need to also enable the “Passthrough” option; see chapter 5.9, CD/DVD support, page 92.
∗ If you select “Remove disk from virtual drive”, VirtualBox will present an empty CD/DVD drive to the guest into which no media has been inserted.

52

3 Conﬁguring virtual machines
• To remove an attachment, select it and click on the “remove” icon at the bottom (or right-click on it and select the menu item).
Removable media (CD/DVDs and ﬂoppies) can be changed while the guest is running. Since the “Settings” dialog is not available at that time, you can also access these settings from the
“Devices” menu of your virtual machine window.

3.7 Audio settings
The “Audio” section in a virtual machine’s Settings window determines whether the VM will see a sound card connected, and whether the audio output should be heard on the host system.
If audio is enabled for a guest, you can choose between the emulation of an Intel AC’97 controller, an Intel HD Audio controller7 or a SoundBlaster 16 card. In any case, you can select what audio driver VirtualBox will use on the host.
On a Linux host, depending on your host conﬁguration, you can also select between the OSS,
ALSA or the PulseAudio subsystem. On newer Linux distributions, the PulseAudio subsystem should be preferred.

3.8 Network settings
The “Network” section in a virtual machine’s Settings window allows you to conﬁgure how
VirtualBox presents virtual network cards to your VM, and how they operate.
When you ﬁrst create a virtual machine, VirtualBox by default enables one virtual network card and selects the “Network Address Translation” (NAT) mode for it. This way the guest can connect to the outside world using the host’s networking and the outside world can connect to services on the guest which you choose to make visible outside of the virtual machine.
This default setup is good for probably 95% of VirtualBox users. However, VirtualBox is extremely ﬂexible in how it can virtualize networking. It supports many virtual network cards per virtual machine, the ﬁrst four of which can be conﬁgured in detail in the Manager window.
Additional network cards can be conﬁgured on the command line with VBoxManage.
Because of the vast array of options available, we have dedicated an entire chapter of this manual to discussing networking conﬁguration; please see chapter 6, Virtual networking, page
94.

3.9 Serial ports
VirtualBox fully supports virtual serial ports in a virtual machine in an easy-to-use manner.8
Ever since the original IBM PC, personal computers have been equipped with one or two serial ports (also called COM ports by DOS and Windows). Serial ports were commonly used with modems, and some computer mice used to be connected to serial ports before USB became commonplace. While serial ports are no longer as ubiquitous as they used to be, there are still some important uses left for them. For example, serial ports can be used to set up a primitive network over a nullmodem cable, in case Ethernet is not available. Also, serial ports are indispensable for system programmers needing to do kernel debugging, since kernel debugging software usually interacts with developers over a serial port. With virtual serial ports, system programmers can do kernel debugging on a virtual machine instead of needing a real computer to connect to.

7 Intel

HD Audio support was added with VirtualBox 4.0 because Windows 7 and later (as well as 64-bit Windows Vista) do not support the Intel AC’97 controller out of the box.
8 Serial port support was added with VirtualBox 1.5.

53

3 Conﬁguring virtual machines
If a virtual serial port is enabled, the guest operating system sees a standard 16550A compatible UART device. Both receiving and transmitting data is supported. How this virtual serial port is then connected to the host is conﬁgurable, and the details depend on your host operating system. You can use either the graphical user interface or the command-line VBoxManage tool to set up virtual serial ports. For the latter, please refer to chapter 8.8, VBoxManage modifyvm, page 129; in that section, look for the --uart and --uartmode options.
In either case, you can conﬁgure up to two virtual serial ports per virtual machine. For each such device, you will need to determine
1. what kind of serial port the virtual machine should see by selecting an I/O base address and interrupt (IRQ). For these, we recommend to use the traditional values9 , which are:
a) COM1: I/O base 0x3F8, IRQ 4
b) COM2: I/O base 0x2F8, IRQ 3
c) COM3: I/O base 0x3E8, IRQ 4
d) COM4: I/O base 0x2E8, IRQ 3
2. Then, you will need to determine what this virtual port should be connected to. For each virtual serial port, you have the following options:
• You can elect to have the virtual serial port “disconnected”, which means that the guest will see the device, but it will behave as if no cable had been connected to it.
• You can connect the virtual serial port to a physical serial port on your host. (On a
Windows host, this will be a name like COM1; on Linux or Solaris hosts, it will be a device node like /dev/ttyS0). VirtualBox will then simply redirect all data received from and sent to the virtual serial port to the physical device.
• You can tell VirtualBox to connect the virtual serial port to a software pipe on the host.
This depends on your host operating system:
– On a Windows host, data will be sent and received through a named pipe. The pipe name must be in the format \\.\pipe\<name> where <name> should identify the virtual machine but may be freely chosen.
– On a Mac, Linux or Solaris host, a local domain socket is used instead. The socket ﬁlename must be chosen such that the user running VirtualBox has sufﬁcient privileges to create and write to it. The /tmp directory is often a good candidate.
On Linux there are various tools which can connect to a local domain socket or create one in server mode. The most ﬂexible tool is socat and is available as part of many distributions.
In this case, you can conﬁgure whether VirtualBox should create the named pipe (or, on non-Windows hosts, the local domain socket) itself or whether VirtualBox should assume that the pipe (or socket) exists already. With the VBoxManage command-line options, this is referred to as “server” or “client” mode, respectively.
For a direct connection between two virtual machines (corresponding to a null-modem cable), simply conﬁgure one VM to create a pipe/socket and another to attach to it.
• You can send the virtual serial port output to a ﬁle. This option is very useful for capturing diagnostic output from a guest. Any ﬁle may be used for this purpose, as long as the user running VirtualBox has sufﬁcient privileges to create and write to the ﬁle. • TCP Socket: Useful for forwarding serial trafﬁc over TCP/IP, acting as a server, or it can act as a TCP client connecting to other servers. It allows a remote machine to directly connect to the guest’s serial port via TCP.
9 See,

for example, http://en.wikipedia.org/wiki/COM_(hardware_interface).

54

3 Conﬁguring virtual machines
– TCP Server: Uncheck the Connect to existing pipe/socket checkbox and specify the port number. Typically 23 or 2023. Note that on UNIX-like systems you will have to use a port a number greater than 1024 for regular users.
The client can use software such as PuTTY or the telnet command line tool to access the TCP Server.
– TCP Client: To create a virtual null-modem cable over the Internet or LAN, the other side can connect via TCP by specifying hostname:port. The TCP socket will act in client mode if check the Connect to existing pipe/socket checkbox.
Up to two serial ports can be conﬁgured per virtual machine, but you can pick any port numbers out of the above. However, serial ports cannot reliably share interrupts; if both ports are to be used at the same time, they must use different interrupt levels, for example COM1 and COM2, but not COM1 and COM3.

3.10 USB support
3.10.1 USB settings
The “USB” section in a virtual machine’s Settings window allows you to conﬁgure VirtualBox’s sophisticated USB support.
VirtualBox can allow virtual machines to access the USB devices on your host directly. To achieve this, VirtualBox presents the guest operating system with a virtual USB controller. As soon as the guest system starts using a USB device, it will appear as unavailable on the host.
Note:
1. Be careful with USB devices that are currently in use on the host! For example, if you allow your guest to connect to your USB hard disk that is currently mounted on the host, when the guest is activated, it will be disconnected from the host without a proper shutdown. This may cause data loss.
2. Solaris hosts have a few known limitations regarding USB support; please see chapter 14, Known limitations, page 247.
In addition to allowing a guest access to your local USB devices, VirtualBox even allows your guests to connect to remote USB devices by use of the VirtualBox Remote Desktop Extension
(VRDE). For details about this, see chapter 7.1.4, Remote USB, page 109.
In the Settings dialog, you can ﬁrst conﬁgure whether USB is available in the guest at all, and then choose the level of USB support: OHCI for USB 1.1, EHCI (which will also enable OHCI) for USB 2.0, or xHCI for all USB speeds.
Note: The xHCI and EHCI controllers are shipped as a VirtualBox extension package, which must be installed separately. See chapter 1.5, Installing VirtualBox and extension packs, page 15 for more information.
When USB support is enabled for a VM, you can determine in detail which devices will be automatically attached to the guest. For this, you can create so-called “ﬁlters” by specifying certain properties of the USB device. USB devices with a matching ﬁlter will be automatically passed to the guest once they are attached to the host. USB devices without a matching ﬁlter can be passed manually to the guest, for example by using the Devices / USB devices menu.
Clicking on the “+“ button to the right of the “USB Device Filters” window creates a new ﬁlter.
You can give the ﬁlter a name (for referencing it later) and specify the ﬁlter criteria. The more

55

3 Conﬁguring virtual machines criteria you specify, the more precisely devices will be selected. For instance, if you specify only a vendor ID of 046d, all devices produced by Logitech will be available to the guest. If you ﬁll in all ﬁelds, on the other hand, the ﬁlter will only apply to a particular device model from a particular vendor, and not even to other devices of the same type with a different revision and serial number.
In detail, the following criteria are available:
1. Vendor and product ID. With USB, each vendor of USB products carries an identiﬁcation number that is unique world-wide, the “vendor ID”. Similarly, each line of products is assigned a “product ID” number. Both numbers are commonly written in hexadecimal
(that is, they are composed of the numbers 0-9 and the letters A-F), and a colon separates the vendor from the product ID. For example, 046d:c016 stands for Logitech as a vendor, and the “M-UV69a Optical Wheel Mouse” product.
Alternatively, you can also specify “Manufacturer” and “Product” by name.
To list all the USB devices that are connected to your host machine with their respective vendor and product IDs, you can use the following command (see chapter 8, VBoxManage, page 115):
VBoxManage list usbhost

On Windows, you can also see all USB devices that are attached to your system in the
Device Manager. On Linux, you can use the lsusb command.
2. Serial number. While vendor and product ID are already quite speciﬁc to identify USB devices, if you have two identical devices of the same brand and product line, you will also need their serial numbers to ﬁlter them out correctly.
3. Remote. This setting speciﬁes whether the device will be local only, or remote only (over
VRDP), or either.
On a Windows host, you will need to unplug and reconnect a USB device to use it after creating a ﬁlter for it.
As an example, you could create a new USB ﬁlter and specify a vendor ID of 046d (Logitech,
Inc), a manufacturer index of 1, and “not remote”. Then any USB devices on the host system produced by Logitech, Inc with a manufacturer index of 1 will be visible to the guest system.
Several ﬁlters can select a single device – for example, a ﬁlter which selects all Logitech devices, and one which selects a particular webcam.
You can deactivate ﬁlters without deleting them by clicking in the checkbox next to the ﬁlter name. 3.10.2 Implementation notes for Windows and Linux hosts
On Windows hosts, a kernel mode device driver provides USB proxy support. It implements both a USB monitor, which allows VirtualBox to capture devices when they are plugged in, and a USB device driver to claim USB devices for a particular virtual machine. As opposed to VirtualBox versions before 1.4.0, system reboots are no longer necessary after installing the driver. Also, you no longer need to replug devices for VirtualBox to claim them.
On newer Linux hosts, VirtualBox accesses USB devices through special ﬁles in the ﬁle system.
When VirtualBox is installed, these are made available to all users in the vboxusers system group. In order to be able to access USB from guest systems, make sure that you are a member of this group.
On older Linux hosts, USB devices are accessed using the usbfs ﬁle system. Therefore, the user executing VirtualBox needs read and write permission to the USB ﬁle system. Most distributions provide a group (e.g. usbusers) which the VirtualBox user needs to be added to. Also,
VirtualBox can only proxy to virtual machines USB devices which are not claimed by a Linux

56

3 Conﬁguring virtual machines host USB driver. The Driver= entry in /proc/bus/usb/devices will show you which devices are currently claimed. Please refer to chapter 12.8.7, USB not working, page 241 also for details about usbfs.

3.11 Shared folders
Shared folders allow you to easily exchange data between a virtual machine and your host. This feature requires that the VirtualBox Guest Additions be installed in a virtual machine and is described in detail in chapter 4.3, Shared folders, page 69.

3.12 Alternative ﬁrmware (EFI)
Starting with release 3.1, VirtualBox includes experimental support for the Extensible Firmware
Interface (EFI), which is a new industry standard intended to eventually replace the legacy BIOS as the primary interface for bootstrapping computers and certain system services later.
By default, VirtualBox uses the BIOS ﬁrmware for virtual machines. To use EFI for a given virtual machine, you can enable EFI in the machine’s “Settings” dialog (see chapter 3.4.1, “Motherboard” tab, page 47). Alternatively, use the VBoxManage command line interface like this:
VBoxManage modifyvm "VM name" --firmware efi

To switch back to using the BIOS, use:
VBoxManage modifyvm "VM name" --firmware bios

One notable user of EFI is Apple’s Mac OS X, but more recent Linuxes and Windows (starting with Vista) offer special versions that can be booted using EFI as well.
Another possible use of EFI in VirtualBox is development and testing of EFI applications, without booting any OS.
Note that the VirtualBox EFI support is experimental and will be enhanced as EFI matures and becomes more widespread. While Mac OS X and Linux guests are known to work ﬁne, Windows guests are currently unable to boot with the VirtualBox EFI implementation.

3.12.1 Video modes in EFI
EFI provides two distinct video interfaces: GOP (Graphics Output Protocol) and UGA (Universal
Graphics Adapter). Mac OS X uses GOP, while Linux tends to use UGA. VirtualBox provides a conﬁguration option to control the framebuffer size for both interfaces.
To control GOP, use the following VBoxManage command:
VBoxManage setextradata "VM name" VBoxInternal2/EfiGopMode N

Where N can be one of 0,1,2,3,4,5 referring to the 640x480, 800x600, 1024x768, 1280x1024,
1440x900, 1920x1200 screen resolution respectively.
To change the UGA resolution:
VBoxManage setextradata "VM name" VBoxInternal2/UgaHorizontalResolution 1440
VBoxManage setextradata "VM name" VBoxInternal2/UgaVerticalResolution
900

The video mode for both GOP and UGA can only be changed when the VM is powered off and remains persistent until changed.

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3 Conﬁguring virtual machines

3.12.2 Specifying boot arguments
It is currently not possible to manipulate EFI variables from within a running guest (e.g., setting the “boot-args” variable by running the nvram tool in a Mac OS X guest will not work). As an alternative way, “VBoxInternal2/EﬁBootArgs” extradata can be passed to a VM in order to set the
“boot-args” variable. To change the “boot-args” EFI variable:
VBoxManage setextradata "VM name" VBoxInternal2/EfiBootArgs <value>

58

4 Guest Additions
The previous chapter covered getting started with VirtualBox and installing operating systems in a virtual machine. For any serious and interactive use, the VirtualBox Guest Additions will make your life much easier by providing closer integration between host and guest and improving the interactive performance of guest systems. This chapter describes the Guest Additions in detail.

4.1 Introduction
As mentioned in chapter 1.2, Some terminology, page 11, the Guest Additions are designed to be installed inside a virtual machine after the guest operating system has been installed. They consist of device drivers and system applications that optimize the guest operating system for better performance and usability. Please see chapter 3.1, Supported guest operating systems, page
43 for details on what guest operating systems are fully supported with Guest Additions by
VirtualBox.
The VirtualBox Guest Additions for all supported guest operating systems are provided as a single CD-ROM image ﬁle which is called VBoxGuestAdditions.iso. This image ﬁle is located in the installation directory of VirtualBox. To install the Guest Additions for a particular VM, you mount this ISO ﬁle in your VM as a virtual CD-ROM and install from there.
The Guest Additions offer the following features:
Mouse pointer integration To overcome the limitations for mouse support that were described in chapter 1.8.2, Capturing and releasing keyboard and mouse, page 21, this provides you with seamless mouse support. You will only have one mouse pointer and pressing the Host key is no longer required to “free” the mouse from being captured by the guest OS. To make this work, a special mouse driver is installed in the guest that communicates with the
“real” mouse driver on your host and moves the guest mouse pointer accordingly.
Shared folders These provide an easy way to exchange ﬁles between the host and the guest.
Much like ordinary Windows network shares, you can tell VirtualBox to treat a certain host directory as a shared folder, and VirtualBox will make it available to the guest operating system as a network share, irrespective of whether guest actually has a network. For details, please refer to chapter 4.3, Shared folders, page 69.
Better video support While the virtual graphics card which VirtualBox emulates for any guest operating system provides all the basic features, the custom video drivers that are installed with the Guest Additions provide you with extra high and non-standard video modes as well as accelerated video performance.
In addition, with Windows, Linux and Solaris guests, you can resize the virtual machine’s window if the Guest Additions are installed. The video resolution in the guest will be automatically adjusted (as if you had manually entered an arbitrary resolution in the guest’s display settings). Please see chapter 1.8.5, Resizing the machine’s window, page 23 also.
Finally, if the Guest Additions are installed, 3D graphics and 2D video for guest applications can be accelerated; see chapter 4.5, Hardware-accelerated graphics, page 73.
Seamless windows With this feature, the individual windows that are displayed on the desktop of the virtual machine can be mapped on the host’s desktop, as if the underlying application was actually running on the host. See chapter 4.6, Seamless windows, page 75 for details.

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4 Guest Additions
Generic host/guest communication channels The Guest Additions enable you to control and monitor guest execution in ways other than those mentioned above. The so-called “guest properties” provide a generic string-based mechanism to exchange data bits between a guest and a host, some of which have special meanings for controlling and monitoring the guest; see chapter 4.7, Guest properties, page 76 for details.
Additionally, applications can be started in a guest from the host; see chapter 4.8, Guest control, page 78.
Time synchronization With the Guest Additions installed, VirtualBox can ensure that the guest’s system time is better synchronized with that of the host.
For various reasons, the time in the guest might run at a slightly different rate than the time on the host. The host could be receiving updates via NTP and its own time might not run linearly. A VM could also be paused, which stops the ﬂow of time in the guest for a shorter or longer period of time. When the wall clock time between the guest and host only differs slightly, the time synchronization service attempts to gradually and smoothly adjust the guest time in small increments to either “catch up” or “lose” time. When the difference is too great (e.g., a VM paused for hours or restored from saved state), the guest time is changed immediately, without a gradual adjustment.
The Guest Additions will re-synchronize the time regularly. See chapter 9.14.3, Tuning the Guest Additions time synchronization parameters, page 192 for how to conﬁgure the parameters of the time synchronization mechanism.
Shared clipboard With the Guest Additions installed, the clipboard of the guest operating system can optionally be shared with your host operating system; see chapter 3.3, General settings, page 46.
Automated logons (credentials passing) For details, please see chapter 9.2, Automated guest logons, page 173.
Each version of VirtualBox, even minor releases, ship with their own version of the Guest
Additions. While the interfaces through which the VirtualBox core communicates with the Guest
Additions are kept stable so that Guest Additions already installed in a VM should continue to work when VirtualBox is upgraded on the host, for best results, it is recommended to keep the
Guest Additions at the same version.
Starting with VirtualBox 3.1, the Windows and Linux Guest Additions therefore check automatically whether they have to be updated. If the host is running a newer VirtualBox version than the Guest Additions, a notiﬁcation with further instructions is displayed in the guest.
To disable this update check for the Guest Additions of a given virtual machine, set the value of its /VirtualBox/GuestAdd/CheckHostVersion guest property to 0; see chapter 4.7, Guest properties, page 76 for details.

4.2 Installing and Maintaining Guest Additions
Guest Additions are available for virtual machines running Windows, Linux, Solaris or OS/2.
The following sections describe the speciﬁcs of each variant in detail.

4.2.1 Guest Additions for Windows
The VirtualBox Windows Guest Additions are designed to be installed in a virtual machine running a Windows operating system. The following versions of Windows guests are supported:
• Microsoft Windows NT 4.0 (any service pack)
• Microsoft Windows 2000 (any service pack)

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4 Guest Additions
• Microsoft Windows XP (any service pack)
• Microsoft Windows Server 2003 (any service pack)
• Microsoft Windows Server 2008
• Microsoft Windows Vista (all editions)
• Microsoft Windows 7 (all editions)
• Microsoft Windows 8 (all editions)
• Microsoft Windows Server 2012
4.2.1.1 Installation
In the “Devices” menu in the virtual machine’s menu bar, VirtualBox has a handy menu item named “Insert Guest Additions CD image”, which mounts the Guest Additions ISO ﬁle inside your virtual machine. A Windows guest should then automatically start the Guest Additions installer, which installs the Guest Additions into your Windows guest. Other guest operating systems (or if automatic start of software on CD is disabled) need manual start of the installer.
Note: For the basic Direct3D acceleration to work in a Windows Guest, you have to install the Guest Additions in “Safe Mode”. This does not apply to the experimental
WDDM Direct3D video driver available for Vista and Windows 7 guests, see chapter
14, Known limitations, page 247 for details.a a The

experimental WDDM driver was added with VirtualBox 4.1.

If you prefer to mount the additions manually, you can perform the following steps:
1. Start the virtual machine in which you have installed Windows.
2. Select “Mount CD/DVD-ROM” from the “Devices” menu in the virtual machine’s menu bar and then “CD/DVD-ROM image”. This brings up the Virtual Media Manager described in chapter 5.3, The Virtual Media Manager, page 85.
3. In the Virtual Media Manager, press the “Add” button and browse your host ﬁle system for the VBoxGuestAdditions.iso ﬁle:
• On a Windows host, you can ﬁnd this ﬁle in the VirtualBox installation directory
(usually under C:\Program files\Oracle\VirtualBox ).
• On Mac OS X hosts, you can ﬁnd this ﬁle in the application bundle of VirtualBox.
(Right click on the VirtualBox icon in Finder and choose Show Package Contents. There it is located in the Contents/MacOS folder.)
• On a Linux host, you can ﬁnd this ﬁle in the additions folder under where you installed VirtualBox (normally /opt/VirtualBox/).
• On Solaris hosts, you can ﬁnd this ﬁle in the additions folder under where you installed VirtualBox (normally /opt/VirtualBox).
4. Back in the Virtual Media Manager, select that ISO ﬁle and press the “Select” button. This will mount the ISO ﬁle and present it to your Windows guest as a CD-ROM.

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Unless you have the Autostart feature disabled in your Windows guest, Windows will now autostart the VirtualBox Guest Additions installation program from the Additions ISO. If the
Autostart feature has been turned off, choose VBoxWindowsAdditions.exe from the CD/DVD drive inside the guest to start the installer.
The installer will add several device drivers to the Windows driver database and then invoke the hardware detection wizard.
Depending on your conﬁguration, it might display warnings that the drivers are not digitally signed. You must conﬁrm these in order to continue the installation and properly install the
Additions.
After installation, reboot your guest operating system to activate the Additions.
4.2.1.2 Updating the Windows Guest Additions
Windows Guest Additions can be updated by running the installation program again, as previously described. This will then replace the previous Additions drivers with updated versions.
Alternatively, you may also open the Windows Device Manager and select “Update driver...“ for two devices:
1. the VirtualBox Graphics Adapter and
2. the VirtualBox System Device.
For each, choose to provide your own driver and use “Have Disk” to point the wizard to the
CD-ROM drive with the Guest Additions.
4.2.1.3 Unattended Installation
As a prerequiste for performing an unattended installation of the VirtualBox Guest Additions on a Windows guest, there need to be Oracle CA (Certiﬁcate Authority) certiﬁcates installed in order to prevent user intervention popus which will undermine a silent installation.
Note: On some Windows versions like Windows 2000 and Windows XP the user intervention popups mentioned above always will be displayed, even after importing the
Oracle certiﬁcates.
Since VirtualBox 4.2 installing those CA certiﬁcates on a Windows guest can be done in an automated fashion using the VBoxCertUtil.exe utility found on the Guest Additions installation
CD in the cert folder:
• Log in as Administrator on the guest.
• Mount the VirtualBox Guest Additions .ISO.
• Open a command line window on the guest and change to the cert folder on the VirtualBox
Guest Additions CD.
• Do
VBoxCertUtil add-trusted-publisher oracle-vbox.cer --root oracle-vbox.cer

This will install the certiﬁcates to the certiﬁcate store. When installing the same certiﬁcate more than once, an appropriate error will be displayed.
Prior to VirtualBox 4.2 the Oracle CA certiﬁcates need to be imported in more manual style using the certutil.exe utility, which is shipped since Windows Vista. For Windows versions before Vista you need to download and install certutil.exe manually. Since the certiﬁcates

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4 Guest Additions are not accompanied on the VirtualBox Guest Additions CD-ROM prior to 4.2, these need to get extracted from a signed VirtualBox executable ﬁrst.
In the following example the needed certiﬁcates will be extracted from the VirtualBox Windows Guest Additions installer on the CD-ROM:
VeriSign Code Signing CA Open the Windows Explorer.
• Right click on VBoxWindowsAdditions-<Architecture>.exe, click on “Properties”
• Go to tab “Digital Signatures”, choose “Oracle Corporation” and click on “Details”
• In tab “General” click on “View Certiﬁcate”
• In tab “Certiﬁcation Path” select “VeriSign Class 3 Public Primary CA”
• Click on “View Certiﬁcate”
• In tab “Details” click on “Copy to File ...“
• In the upcoming wizard choose “DER encoded binary X.509 (.CER)“ and save the certiﬁcate ﬁle to a local path, ﬁnish the wizard
• Close certiﬁcate dialog for “Verisign Class 3 Code Signing 2010 CA”
Oracle Corporation Open the Windows Explorer.
• Right click on VBoxWindowsAdditions-<Architecture>.exe, click on “Properties”
• Go to tab “Digital Signatures”, choose “Oracle Corporation” and click on “Details”
• In tab “General” click on “View Certiﬁcate”
• In tab “Details” click on “Copy to File ...“
• In the upcoming wizard choose “DER encoded binary X.509 (.CER)“ and save the certiﬁcate ﬁle to a local path, ﬁnish the wizard
• Close certiﬁcate dialog for “Oracle Corporation”
After exporting the two certiﬁcates above they can be imported into the certiﬁcate store using the certutil.exe utility: certutil -addstore -f Root "<Path to exported certificate file>"

In order to allow for completely unattended guest installations, you can specify a command line parameter to the install launcher:
VBoxWindowsAdditions.exe /S

This automatically installs the right ﬁles and drivers for the corresponding platform (32- or
64-bit).
Note: By default on an unattended installation on a Windows 7 or 8 guest, there will be the XPDM graphics driver installed. This graphics driver does not support Windows Aero / Direct3D on the guest - instead the experimental WDDM graphics driver needs to be installed. To select this driver by default, add the command line parameter
/with_wddm when invoking the Windows Guest Additions installer.

Note: For Windows Aero to run correctly on a guest, the guest’s VRAM size needs to be conﬁgured to at least 128 MB.
For more options regarding unattended guest installations, consult the command line help by using the command:
VBoxWindowsAdditions.exe /?

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4 Guest Additions
4.2.1.4 Manual ﬁle extraction
If you would like to install the ﬁles and drivers manually, you can extract the ﬁles from the
Windows Guest Additions setup by typing:
VBoxWindowsAdditions.exe /extract

To explicitly extract the Windows Guest Additions for another platform than the current running one (e.g. 64-bit ﬁles on a 32-bit system), you have to execute the appropriate platform installer (VBoxWindowsAdditions-x86.exe or VBoxWindowsAdditions-amd64.exe) with the
/extract parameter.

4.2.2 Guest Additions for Linux
Like the Windows Guest Additions, the VirtualBox Guest Additions for Linux are a set of device drivers and system applications which may be installed in the guest operating system.
The following Linux distributions are ofﬁcially supported:
• Oracle Linux as of version 5 including UEK kernels;
• Fedora as of Fedora Core 4;
• Redhat Enterprise Linux as of version 3;
• SUSE and openSUSE Linux as of version 9;
• Ubuntu as of version 5.10.
Many other distributions are known to work with the Guest Additions.
The version of the Linux kernel supplied by default in SUSE and openSUSE 10.2, Ubuntu 6.10
(all versions) and Ubuntu 6.06 (server edition) contains a bug which can cause it to crash during startup when it is run in a virtual machine. The Guest Additions work in those distributions.
Note that some Linux distributions already come with all or part of the VirtualBox Guest
Additions. You may choose to keep the distribution’s version of the Guest Additions but these are often not up to date and limited in functionality, so we recommend replacing them with the
Guest Additions that come with VirtualBox. The VirtualBox Linux Guest Additions installer tries to detect existing installation and replace them but depending on how the distribution integrates the Guest Additions, this may require some manual interaction. It is highly recommended to take a snapshot of the virtual machine before replacing pre-installed Guest Additions.
4.2.2.1 Installing the Linux Guest Additions
The VirtualBox Guest Additions for Linux are provided on the same virtual CD-ROM ﬁle as the
Guest Additions for Windows described above. They also come with an installation program guiding you through the setup process, although, due to the signiﬁcant differences between
Linux distributions, installation may be slightly more complex.
Installation generally involves the following steps:
1. Before installing the Guest Additions, you will have to prepare your guest system for building external kernel modules. This works similarly as described in chapter 2.3.2, The
VirtualBox kernel module, page 36, except that this step must now be performed in your
Linux guest instead of on a Linux host system, as described there.
Again, as with Linux hosts, we recommend using DKMS if it is available for the guest system. If it is not installed, use this command for Ubuntu/Debian systems: sudo apt-get install dkms

or for Fedora systems:

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4 Guest Additions yum install dkms

Be sure to install DKMS before installing the Linux Guest Additions. If DKMS is not available or not installed, the guest kernel modules will need to be recreated manually whenever the guest kernel is updated using the command rcvboxadd setup

as root.
2. Insert the VBoxGuestAdditions.iso CD ﬁle into your Linux guest’s virtual CD-ROM drive, exactly the same way as described for a Windows guest in chapter 4.2.1.1, Installation, page
61.
3. Change to the directory where your CD-ROM drive is mounted and execute as root: sh ./VBoxLinuxAdditions.run

For your convenience, we provide the following step-by-step instructions for freshly installed copies of recent versions of the most popular Linux distributions. After these preparational steps, you can execute the VirtualBox Guest Additions installer as described above.
Ubuntu
1. In order to fully update your guest system, open a terminal and run apt-get update

as root followed by apt-get upgrade

2. Install DKMS using apt-get install dkms

3. Reboot your guest system in order to activate the updates and then proceed as described above. Fedora
1. In order to fully update your guest system, open a terminal and run yum update

as root.
2. Install DKMS and the GNU C compiler using yum install dkms

followed by yum install gcc

3. Reboot your guest system in order to activate the updates and then proceed as described above. 65

4 Guest Additions openSUSE 1. In order to fully update your guest system, open a terminal and run zypper update

as root.
2. Install the make tool and the GNU C compiler using zypper install make gcc

3. Reboot your guest system in order to activate the updates.
4. Find out which kernel you are running using uname -a

An example would be 2.6.31.12-0.2-default which refers to the “default” kernel. Then install the correct kernel development package. In the above example this would be zypper install kernel-default-devel

5. Make sure that your running kernel (uname -a) and the kernel packages you have installed
(rpm -qa kernel\*) have the exact same version number. Proceed with the installation as described above.
SuSE Linux Enterprise Desktop (SLED)
1. In order to fully update your guest system, open a terminal and run zypper update

as root.
2. Install the GNU C compiler using zypper install gcc

3. Reboot your guest system in order to activate the updates.
4. Find out which kernel you are running using uname -a

An example would be 2.6.27.19-5.1-default which refers to the “default” kernel. Then install the correct kernel development package. In the above example this would be zypper install kernel-syms kernel-source

5. Make sure that your running kernel (uname -a) and the kernel packages you have installed
(rpm -qa kernel\*) have the exact same version number. Proceed with the installation as described above.
Mandrake
1. Mandrake ships with the VirtualBox Guest Additions which will be replaced if you follow these steps.
2. In order to fully update your guest system, open a terminal and run urpmi --auto-update

as root.
3. Reboot your system in order to activate the updates.
4. Install DKMS using urpmi dkms

and make sure to choose the correct kernel-devel package when asked by the installer (use uname -a to compare).

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Oracle Linux, Red Hat Enterprise Linux and CentOS
1. For versions prior to 6, add divider=10 to the kernel boot options in /etc/grub.conf to reduce the idle CPU load.
2. In order to fully update your guest system, open a terminal and run yum update

as root.
3. Install the GNU C compiler and the kernel development packages using yum install gcc

followed by yum install kernel-devel

For Oracle UEK kernels, use yum install kernel-uek-devel

to install the UEK kernel headers.
4. Reboot your guest system in order to activate the updates and then proceed as described above. 5. In case Oracle Linux does not ﬁnd the required packages, you either have to install them from a different source (e.g. DVD) or use Oracle’s public Yum server located at http:
//public-yum.oracle.com.
Debian
1. In order to fully update your guest system, open a terminal and run apt-get update

as root followed by apt-get upgrade

2. Install the make tool and the GNU C compiler using apt-get install make gcc

3. Reboot your guest system in order to activate the updates.
4. Determine the exact version of your kernel using uname -a and install the correct version of the linux-headers package, e.g. using apt-get install linux-headers-2.6.26-2-686

4.2.2.2 Graphics and mouse integration
In Linux and Solaris guests, VirtualBox graphics and mouse integration goes through the X Window System. VirtualBox can use the X.Org variant of the system (or XFree86 version 4.3 which is identical to the ﬁrst X.Org release). During the installation process, the X.Org display server will be set up to use the graphics and mouse drivers which come with the Guest Additions.
After installing the Guest Additions into a fresh installation of a supported Linux distribution or Solaris system (many unsupported systems will work correctly too), the guest’s graphics mode will change to ﬁt the size of the VirtualBox window on the host when it is resized. You can also ask the guest system to switch to a particular resolution by sending a “video mode hint” using the VBoxManage tool.

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4 Guest Additions
Multiple guest monitors are supported in guests using the X.Org server version 1.3 (which is part of release 7.3 of the X Window System version 11) or a later version. The layout of the guest screens can be adjusted as needed using the tools which come with the guest operating system.
If you want to understand more about the details of how the X.Org drivers are set up (in particular if you wish to use them in a setting which our installer doesn’t handle correctly), you should read chapter 9.4.2, Guest graphics and mouse driver setup in depth, page 178.
4.2.2.3 Updating the Linux Guest Additions
The Guest Additions can simply be updated by going through the installation procedure again with an updated CD-ROM image. This will replace the drivers with updated versions. You should reboot after updating the Guest Additions.
4.2.2.4 Uninstalling the Linux Guest Additions
If you have a version of the Guest Additions installed on your virtual machine and wish to remove it without installing new ones, you can do so by inserting the Guest Additions CD image into the virtual CD-ROM drive as described above and running the installer for the current Guest
Additions with the “uninstall” parameter from the path that the CD image is mounted on in the guest: sh ./VBoxLinuxAdditions.run uninstall

While this will normally work without issues, you may need to do some manual cleanup of the guest (particularly of the XFree86Conﬁg or xorg.conf ﬁle) in some cases, particularly if the
Additions version installed or the guest operating system were very old, or if you made your own changes to the Guest Additions setup after you installed them.
Starting with version 3.1.0, you can uninstall the Additions by invoking
/opt/VBoxGuestAdditions-5.0.0/uninstall.sh

Please replace /opt/VBoxGuestAdditions-5.0.0 with the correct Guest Additions installation directory. 4.2.3 Guest Additions for Solaris
Like the Windows Guest Additions, the VirtualBox Guest Additions for Solaris take the form of a set of device drivers and system applications which may be installed in the guest operating system. The following Solaris distributions are ofﬁcially supported:
• Solaris 11 including Solaris 11 Express;
• Solaris 10 (u5 and higher);
Other distributions may work if they are based on comparable software releases.
4.2.3.1 Installing the Solaris Guest Additions
The VirtualBox Guest Additions for Solaris are provided on the same ISO CD-ROM as the Additions for Windows and Linux described above. They also come with an installation program guiding you through the setup process.
Installation involves the following steps:

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4 Guest Additions
1. Mount the VBoxGuestAdditions.iso ﬁle as your Solaris guest’s virtual CD-ROM drive, exactly the same way as described for a Windows guest in chapter 4.2.1.1, Installation, page 61.
If in case the CD-ROM drive on the guest doesn’t get mounted (observed on some versions of Solaris 10), execute as root: svcadm restart volfs

2. Change to the directory where your CD-ROM drive is mounted and execute as root: pkgadd -G -d ./VBoxSolarisAdditions.pkg

3. Choose “1” and conﬁrm installation of the Guest Additions package. After the installation is complete, re-login to X server on your guest to activate the X11 Guest Additions.
4.2.3.2 Uninstalling the Solaris Guest Additions
The Solaris Guest Additions can be safely removed by removing the package from the guest.
Open a root terminal session and execute: pkgrm SUNWvboxguest

4.2.3.3 Updating the Solaris Guest Additions
The Guest Additions should be updated by ﬁrst uninstalling the existing Guest Additions and then installing the new ones. Attempting to install new Guest Additions without removing the existing ones is not possible.

4.2.4 Guest Additions for OS/2
VirtualBox also ships with a set of drivers that improve running OS/2 in a virtual machine. Due to restrictions of OS/2 itself, this variant of the Guest Additions has a limited feature set; see chapter 14, Known limitations, page 247 for details.
The OS/2 Guest Additions are provided on the same ISO CD-ROM as those for the other platforms. As a result, mount the ISO in OS/2 as described previously. The OS/2 Guest Additions are located in the directory \32bit\OS2.
As we do not provide an automatic installer at this time, please refer to the readme.txt ﬁle in that directory, which describes how to install the OS/2 Guest Additions manually.

4.3 Shared folders
With the “shared folders” feature of VirtualBox, you can access ﬁles of your host system from within the guest system. This is similar how you would use network shares in Windows networks
– except that shared folders do not need require networking, only the Guest Additions. Shared
Folders are supported with Windows (2000 or newer), Linux and Solaris guests.
Shared folders must physically reside on the host and are then shared with the guest, which uses a special ﬁle system driver in the Guest Addition to talk to the host. For Windows guests, shared folders are implemented as a pseudo-network redirector; for Linux and Solaris guests, the Guest Additions provide a virtual ﬁle system.
To share a host folder with a virtual machine in VirtualBox, you must specify the path of that folder and choose for it a “share name” that the guest can use to access it. Hence, ﬁrst create the shared folder on the host; then, within the guest, connect to it.
There are several ways in which shared folders can be set up for a particular virtual machine:
• In the window of a running VM, you can select “Shared folders” from the “Devices” menu, or click on the folder icon on the status bar in the bottom right corner.

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4 Guest Additions
• If a VM is not currently running, you can conﬁgure shared folders in each virtual machine’s
“Settings” dialog.
• From the command line, you can create shared folders using VBoxManage, as follows:
VBoxManage sharedfolder add "VM name" --name "sharename" --hostpath "C:\test"

See chapter 8.29, VBoxManage sharedfolder add/remove, page 152 for details.
There are two types of shares:
1. VM shares which are only available to the VM for which they have been deﬁned;
2. transient VM shares, which can be added and removed at runtime and do not persist after a VM has stopped; for these, add the --transient option to the above command line.
Shared folders have read/write access to the ﬁles at the host path by default. To restrict the guest to have read-only access, create a read-only shared folder. This can either be achieved using the GUI or by appending the parameter --readonly when creating the shared folder with
VBoxManage.
Starting with version 4.0, VirtualBox shared folders also support symbolic links (symlinks), under the following conditions:
1. The host operating system must support symlinks (i.e. a Mac, Linux or Solaris host is required). 2. Currently only Linux and Solaris Guest Additions support symlinks.
3. For security reasons the guest OS is not allowed to create symlinks by default. If you trust the guest OS to not abuse the functionality, you can enable creation of symlinks for
“sharename” with:
VBoxManage setextradata "VM name" VBoxInternal2/SharedFoldersEnableSymlinksCreate/sharename 1

4.3.1 Manual mounting
You can mount the shared folder from inside a VM the same way as you would mount an ordinary network share:
• In a Windows guest, shared folders are browseable and therefore visible in Windows Explorer. So, to attach the host’s shared folder to your Windows guest, open Windows Explorer and look for it under “My Networking Places” -> “Entire Network” -> “VirtualBox
Shared Folders”. By right-clicking on a shared folder and selecting “Map network drive” from the menu that pops up, you can assign a drive letter to that shared folder.
Alternatively, on the Windows command line, use the following: net use x: \\vboxsvr\sharename

While vboxsvr is a ﬁxed name (note that vboxsrv would also work), replace “x:“ with the drive letter that you want to use for the share, and sharename with the share name speciﬁed with VBoxManage.
• In a Linux guest, use the following command: mount -t vboxsf [-o OPTIONS] sharename mountpoint

To mount a shared folder during boot, add the following entry to /etc/fstab: sharename mountpoint

vboxsf

defaults

0

• In a Solaris guest, use the following command:

70

0

4 Guest Additions mount -F vboxfs [-o OPTIONS] sharename mountpoint

Replace sharename (use lowercase) with the share name speciﬁed with VBoxManage or the
GUI, and mountpoint with the path where you want the share to be mounted on the guest
(e.g. /mnt/share). The usual mount rules apply, that is, create this directory ﬁrst if it does not exist yet.
Here is an example of mounting the shared folder for the user “jack” on Solaris:
$ id uid=5000(jack) gid=1(other)
$ mkdir /export/home/jack/mount
$ pfexec mount -F vboxfs -o uid=5000,gid=1 jackshare /export/home/jack/mount
$ cd ~/mount
$ ls sharedfile1.mp3 sharedfile2.txt
$

Beyond the standard options supplied by the mount command, the following are available: iocharset CHARSET

to set the character set used for I/O operations. Note that on Linux guests, if the “iocharset” option is not speciﬁed then the Guest Additions driver will attempt to use the character set speciﬁed by the CONFIG_NLS_DEFAULT kernel option. If this option is not set either then
UTF-8 will be used. Also, convertcp CHARSET

is available in order to specify the character set used for the shared folder name (utf8 by default). The generic mount options (documented in the mount manual page) apply also. Especially useful are the options uid, gid and mode, as they allow access by normal users (in read/write mode, depending on the settings) even if root has mounted the ﬁlesystem.

4.3.2 Automatic mounting
Starting with version 4.0, VirtualBox can mount shared folders automatically, at your option. If automatic mounting is enabled for a speciﬁc shared folder, the Guest Additions will automatically mount that folder as soon as a user logs into the guest OS. The details depend on the guest OS type: • With Windows guests, any auto-mounted shared folder will receive its own drive letter
(e.g. E:) depending on the free drive letters remaining in the guest.
If there no free drive letters left, auto-mounting will fail; as a result, the number of automounted shared folders is typically limited to 22 or less with Windows guests.
• With Linux guests, auto-mounted shared folders are mounted into the /media directory, along with the preﬁx sf_. For example, the shared folder myfiles would be mounted to
/media/sf_myfiles on Linux and /mnt/sf_myfiles on Solaris.
The guest property /VirtualBox/GuestAdd/SharedFolders/MountPrefix determines the preﬁx that is used. Change that guest property to a value other than “sf” to change that preﬁx; see chapter 4.7, Guest properties, page 76 for details.
Note: Access to auto-mounted shared folders is only granted to the user group vboxsf, which is created by the VirtualBox Guest Additions installer. Hence guest users have to be member of that group to have read/write access or to have read-only access in case the folder is not mapped writable.

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To change the mount directory to something other than /media, you can set the guest property /VirtualBox/GuestAdd/SharedFolders/MountDir.
• Solaris guests behave like Linux guests except that /mnt is used as the default mount directory instead of /media.
To have any changes to auto-mounted shared folders applied while a VM is running, the guest
OS needs to be rebooted. (This applies only to auto-mounted shared folders, not the ones which are mounted manually.)

4.4 Drag’n Drop
Starting with version 5.0, VirtualBox supports to drag’n drop content from the host to the guest and vice versa. For this to work the latest Guest Additions must be installed on the guest.
Drag’n drop transparently allows copying or opening ﬁles, directories and even certain clipboard formats from one end to the other, e.g. from the host to the guest or from the guest to the host. One then can perform drag’n drop operations between the host and a VM as it would be a native drag’n drop operation on the host OS.
At the moment drag’n drop is implemented for Windows- and X-Windows-based systems, both, on host and guest side. As X-Windows sports different drag’n drop protocols only the most used one, XDND, is supported for now. Applications using other protocols (such as Motif or OfﬁX) will not be recognized by VirtualBox.
In context of using drag’n drop the origin of the data is called source, that is, where the actual data comes from and is speciﬁed. On the other hand there is the target, which speciﬁes where the data from the source should go to. Transferring data from the source to the target can be done in various ways, e.g. copying, moving or linking.1
When transferring data from the host to the guest OS, the host in this case is the source, whereas the guest OS is the target. However, when doing it the other way around, that is, transferring data from the guest OS to the host, the guest OS this time became the source and the host is the target.
For security reasons drag’n drop can be conﬁgured at runtime on a per-VM basis either using the “Drag’n’Drop” menu item in the “Devices” menu of the virtual machine or VBoxManage: The following four modes are available:

• Disabled disables the drag’n drop entirely. This is the default when creating new VMs.
• Host To Guest enables performing drag’n drop operations from the host to the guest only.
• Guest To Host enables performing drag’n drop operations from the guest to the host only.
1 At

the moment only copying of data is supported. Moving or linking is not yet implemented.

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• Bidirectional enables performing drag’n drop operations to both directions, e.g. from the host to the guest and vice versa.

Note: Drag’n drop support depends on the frontend being used; at the moment only the VirtualBox Manager frontend provides this functionality.
To use VBoxManage for controlling the current drag’n drop mode, see chapter 8, VBoxManage, page 115. The commands modifyvm and controlvm allow setting the VM’s current drag’n drop mode via command line.

4.4.1 Supported formats
As VirtualBox can run on a variety of host OSes and also supports a wide range of guests, certain data formats must be translated after those got transfered over so that the target OS (that is, the side which receiving the data) is able to handle them in an appropriate manner.
Note: When dragging ﬁles however, no data conversion is done in any way, e.g. when transferring a ﬁle from a Linux guest to a Windows host the Linux-speciﬁc line endings won’t be converted to Windows ones.
The following formats are handled by the VirtualBox drag’n drop service:
• Plain text, from applications such as text editors, internet browsers and terminal windows
• Files, from ﬁle managers such as Windows explorer, Nautilus and Finder
• Directories, where the same applies as for ﬁles

4.5 Hardware-accelerated graphics
4.5.1 Hardware 3D acceleration (OpenGL and Direct3D 8/9)
The VirtualBox Guest Additions contain experimental hardware 3D support for Windows, Linux and Solaris guests.2
With this feature, if an application inside your virtual machine uses 3D features through the
OpenGL or Direct3D 8/9 programming interfaces, instead of emulating them in software (which would be slow), VirtualBox will attempt to use your host’s 3D hardware. This works for all supported host platforms (Windows, Mac, Linux, Solaris), provided that your host operating system can make use of your accelerated 3D hardware in the ﬁrst place.
The 3D acceleration currently has the following preconditions:
1. It is only available for certain Windows, Linux and Solaris guests. In particular:
• 3D acceleration with Windows guests requires Windows 2000, Windows XP, Vista or
Windows 7. Both OpenGL and Direct3D 8/9 (not with Windows 2000) are supported
(experimental).
• OpenGL on Linux requires kernel 2.6.27 and higher as well as X.org server version 1.5 and higher. Ubuntu 10.10 and Fedora 14 have been tested and conﬁrmed as working.
2 OpenGL

support for Windows guests was added with VirtualBox 2.1; support for Linux and Solaris followed with
VirtualBox 2.2. With VirtualBox 3.0, Direct3D 8/9 support was added for Windows guests. OpenGL 2.0 is now supported as well. With VirtualBox 4.1 Windows Aero theme support is added for Windows Vista and Windows 7 guests (experimental)

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• OpenGL on Solaris guests requires X.org server version 1.5 and higher.
2. The Guest Additions must be installed.
Note: For the basic Direct3D acceleration to work in a Windows Guest, VirtualBox needs to replace Windows system ﬁles in the virtual machine. As a result, the Guest
Additions installation program offers Direct3D acceleration as an option that must be explicitly enabled. Also, you must install the Guest Additions in “Safe Mode”. This does not apply to the experimental WDDM Direct3D video driver available for Vista and Windows 7 guests, see chapter 14, Known limitations, page 247 for details.

3. Because 3D support is still experimental at this time, it is disabled by default and must be manually enabled in the VM settings (see chapter 3.3, General settings, page 46).
Note: Untrusted guest systems should not be allowed to use VirtualBox’s 3D acceleration features, just as untrusted host software should not be allowed to use 3D acceleration. Drivers for 3D hardware are generally too complex to be made properly secure and any software which is allowed to access them may be able to compromise the operating system running them. In addition, enabling 3D acceleration gives the guest direct access to a large body of additional program code in the VirtualBox host process which it might conceivably be able to use to crash the virtual machine.

With VirtualBox 4.1, Windows Aero theme support is added for Windows Vista and Windows 7 guests. To enable Aero theme support, the experimental VirtualBox WDDM video driver must be installed, which is available with the Guest Additions installation. Since the WDDM video driver is still experimental at this time, it is not installed by default and must be manually selected in the Guest Additions installer by answering “No” int the “Would you like to install basic Direct3D support” dialog displayed when the Direct3D feature is selected.
Note: Unlike the current basic Direct3D support, the WDDM video driver installation does not require the “Safe Mode”.
The Aero theme is not enabled by default. To enable it
• In Windows Vista guest: right-click on the desktop, in the context menu select “Personalize”, then select “Windows Color and Appearance” in the “Personalization” window, in the
“Appearance Settings” dialog select “Windows Aero” and press “OK”
• In Windows 7 guest: right-click on the desktop, in the context menu select “Personalize” and select any Aero theme in the “Personalization” window
Technically, VirtualBox implements this by installing an additional hardware 3D driver inside your guest when the Guest Additions are installed. This driver acts as a hardware 3D driver and reports to the guest operating system that the (virtual) hardware is capable of 3D hardware acceleration. When an application in the guest then requests hardware acceleration through the OpenGL or Direct3D programming interfaces, these are sent to the host through a special communication tunnel implemented by VirtualBox, and then the host performs the requested 3D operation via the host’s programming interfaces.

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4.5.2 Hardware 2D video acceleration for Windows guests
Starting with version 3.1, the VirtualBox Guest Additions contain experimental hardware 2D video acceleration support for Windows guests.
With this feature, if an application (e.g. a video player) inside your Windows VM uses 2D video overlays to play a movie clip, then VirtualBox will attempt to use your host’s video acceleration hardware instead of performing overlay stretching and color conversion in software (which would be slow). This currently works for Windows, Linux and Mac host platforms, provided that your host operating system can make use of 2D video acceleration in the ﬁrst place.
The 2D video acceleration currently has the following preconditions:
1. It is only available for Windows guests (XP or later).
2. The Guest Additions must be installed.
3. Because 2D support is still experimental at this time, it is disabled by default and must be manually enabled in the VM settings (see chapter 3.3, General settings, page 46).
Technically, VirtualBox implements this by exposing video overlay DirectDraw capabilities in the Guest Additions video driver. The driver sends all overlay commands to the host through a special communication tunnel implemented by VirtualBox. On the host side, OpenGL is then used to implement color space transformation and scaling

4.6 Seamless windows
With the “seamless windows” feature of VirtualBox, you can have the windows that are displayed within a virtual machine appear side by side next to the windows of your host. This feature is supported for the following guest operating systems (provided that the Guest Additions are installed): • Windows guests (support added with VirtualBox 1.5);
• Supported Linux or Solaris guests running the X Window System (added with VirtualBox
1.6).
After seamless windows are enabled (see below), VirtualBox suppresses the display of the
Desktop background of your guest, allowing you to run the windows of your guest operating system seamlessly next to the windows of your host:

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To enable seamless mode, after starting the virtual machine, press the Host key (normally the right control key) together with “L”. This will enlarge the size of the VM’s display to the size of your host screen and mask out the guest operating system’s background. To go back to the
“normal” VM display (i.e. to disable seamless windows), press the Host key and “L” again.

4.7 Guest properties
Starting with version 2.1, VirtualBox allows for requesting certain properties from a running guest, provided that the VirtualBox Guest Additions are installed and the VM is running. This is good for two things:
1. A number of predeﬁned VM characteristics are automatically maintained by VirtualBox and can be retrieved on the host, e.g. to monitor VM performance and statistics.
2. In addition, arbitrary string data can be exchanged between guest and host. This works in both directions.
To accomplish this, VirtualBox establishes a private communication channel between the
VirtualBox Guest Additions and the host, and software on both sides can use this channel to exchange string data for arbitrary purposes. Guest properties are simply string keys to which a value is attached. They can be set (written to) by either the host and the guest, and they can also be read from both sides.
In addition to establishing the general mechanism of reading and writing values, a set of predeﬁned guest properties is automatically maintained by the VirtualBox Guest Additions to allow for retrieving interesting guest data such as the guest’s exact operating system and service pack level, the installed version of the Guest Additions, users that are currently logged into the guest OS, network statistics and more. These predeﬁned properties are all preﬁxed with
/VirtualBox/ and organized into a hierarchical tree of keys.
Some of this runtime information is shown when you select “Session Information Dialog” from a virtual machine’s “Machine” menu.
A more ﬂexible way to use this channel is via the VBoxManage guestproperty command set; see chapter 8.30, VBoxManage guestproperty, page 152 for details. For example, to have all the available guest properties for a given running VM listed with their respective values, use this:

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$ VBoxManage guestproperty enumerate "Windows Vista III"
VirtualBox Command Line Management Interface Version 5.0.0
(C) 2005-2015 Oracle Corporation
All rights reserved.
Name: /VirtualBox/GuestInfo/OS/Product, value: Windows Vista Business Edition, timestamp: 1229098278843087000, flags:
Name: /VirtualBox/GuestInfo/OS/Release, value: 6.0.6001, timestamp: 1229098278950553000, flags:
Name: /VirtualBox/GuestInfo/OS/ServicePack, value: 1, timestamp: 1229098279122627000, flags:
Name: /VirtualBox/GuestAdd/InstallDir, value: C:/Program Files/Oracle/VirtualBox
Guest Additions, timestamp: 1229098279269739000, flags:
Name: /VirtualBox/GuestAdd/Revision, value: 40720, timestamp: 1229098279345664000, flags:
Name: /VirtualBox/GuestAdd/Version, value: 5.0.0, timestamp: 1229098279479515000, flags:
Name: /VirtualBox/GuestAdd/Components/VBoxControl.exe, value: 5.0.0r40720, timestamp: 1229098279651731000, flags:
Name: /VirtualBox/GuestAdd/Components/VBoxHook.dll, value: 5.0.0r40720, timestamp: 1229098279804835000, flags:
Name: /VirtualBox/GuestAdd/Components/VBoxDisp.dll, value: 5.0.0r40720, timestamp: 1229098279880611000, flags:
Name: /VirtualBox/GuestAdd/Components/VBoxMRXNP.dll, value: 5.0.0r40720, timestamp: 1229098279882618000, flags:
Name: /VirtualBox/GuestAdd/Components/VBoxService.exe, value: 5.0.0r40720, timestamp: 1229098279883195000, flags:
Name: /VirtualBox/GuestAdd/Components/VBoxTray.exe, value: 5.0.0r40720, timestamp: 1229098279885027000, flags:
Name: /VirtualBox/GuestAdd/Components/VBoxGuest.sys, value: 5.0.0r40720, timestamp: 1229098279886838000, flags:
Name: /VirtualBox/GuestAdd/Components/VBoxMouse.sys, value: 5.0.0r40720, timestamp: 1229098279890600000, flags:
Name: /VirtualBox/GuestAdd/Components/VBoxSF.sys, value: 5.0.0r40720, timestamp: 1229098279893056000, flags:
Name: /VirtualBox/GuestAdd/Components/VBoxVideo.sys, value: 5.0.0r40720, timestamp: 1229098279895767000, flags:
Name: /VirtualBox/GuestInfo/OS/LoggedInUsers, value: 1, timestamp: 1229099826317660000, flags:
Name: /VirtualBox/GuestInfo/OS/NoLoggedInUsers, value: false, timestamp: 1229098455580553000, flags:
Name: /VirtualBox/GuestInfo/Net/Count, value: 1, timestamp: 1229099826299785000, flags:
Name: /VirtualBox/HostInfo/GUI/LanguageID, value: C, timestamp: 1229098151272771000, flags:
Name: /VirtualBox/GuestInfo/Net/0/V4/IP, value: 192.168.2.102, timestamp: 1229099826300088000, flags:
Name: /VirtualBox/GuestInfo/Net/0/V4/Broadcast, value: 255.255.255.255, timestamp: 1229099826300220000, flags:
Name: /VirtualBox/GuestInfo/Net/0/V4/Netmask, value: 255.255.255.0, timestamp: 1229099826300350000, flags:
Name: /VirtualBox/GuestInfo/Net/0/Status, value: Up, timestamp: 1229099826300524000, flags:
Name: /VirtualBox/GuestInfo/OS/LoggedInUsersList, value: username, timestamp: 1229099826317386000, flags:

To query the value of a single property, use the “get” subcommand like this:
$ VBoxManage guestproperty get "Windows Vista III" "/VirtualBox/GuestInfo/OS/Product"
VirtualBox Command Line Management Interface Version 5.0.0
(C) 2005-2015 Oracle Corporation
All rights reserved.
Value: Windows Vista Business Edition

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To add or change guest properties from the guest, use the tool VBoxControl. This tool is included in the Guest Additions of VirtualBox 2.2 or later. When started from a Linux guest, this tool requires root privileges for security reasons:
$ sudo VBoxControl guestproperty enumerate
VirtualBox Guest Additions Command Line Management Interface Version 5.0.0
(C) 2009-2015 Oracle Corporation
All rights reserved.
Name: /VirtualBox/GuestInfo/OS/Release, value: 2.6.28-18-generic, timestamp: 1265813265835667000, flags: <NULL>
Name: /VirtualBox/GuestInfo/OS/Version, value: #59-Ubuntu SMP Thu Jan 28 01:23:03 UTC 2010, timestamp: 1265813265836305000, flags: <NULL>
...

For more complex needs, you can use the VirtualBox programming interfaces; see chapter 11,
VirtualBox programming interfaces, page 225.

4.8 Guest control
Starting with version 3.2, the Guest Additions of VirtualBox allow starting applications inside a
VM from the host system.
For this to work, the application needs to be installed inside the guest; no additional software needs to be installed on the host. Additionally, text mode output (to stdout and stderr) can be shown on the host for further processing along with options to specify user credentials and a timeout value (in milliseconds) to limit time the application is able to run.
This feature can be used to automate deployment of software within the guest.
Starting with version 4.0, the Guest Additions for Windows allow for automatic updating (only already installed Guest Additions 4.0 or later). Also, copying ﬁles from host to the guest as well as remotely creating guest directories is available.
To use these features, use the VirtualBox command line, see chapter 8.31, VBoxManage guestcontrol, page 153.

4.9 Memory overcommitment
In server environments with many VMs; the Guest Additions can be used to share physical host memory between several VMs, reducing the total amount of memory in use by the VMs. If memory usage is the limiting factor and CPU resources are still available, this can help with packing more VMs on each host.

4.9.1 Memory ballooning
Starting with version 3.2, the Guest Additions of VirtualBox can change the amount of host memory that a VM uses while the machine is running. Because of how this is implemented, this feature is called “memory ballooning”.
Note: VirtualBox supports memory ballooning only on 64-bit hosts, and it is not supported on Mac OS X hosts.
Normally, to change the amount of memory allocated to a virtual machine, one has to shut down the virtual machine entirely and modify its settings. With memory ballooning, memory that was allocated for a virtual machine can be given to another virtual machine without having to shut the machine down.

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When memory ballooning is requested, the VirtualBox Guest Additions (which run inside the guest) allocate physical memory from the guest operating system on the kernel level and lock this memory down in the guest. This ensures that the guest will not use that memory any longer: no guest applications can allocate it, and the guest kernel will not use it either. VirtualBox can then re-use this memory and give it to another virtual machine.
The memory made available through the ballooning mechanism is only available for re-use by
VirtualBox. It is not returned as free memory to the host. Requesting balloon memory from a running guest will therefore not increase the amount of free, unallocated memory on the host.
Effectively, memory ballooning is therefore a memory overcommitment mechanism for multiple virtual machines while they are running. This can be useful to temporarily start another machine, or in more complicated environments, for sophisticated memory management of many virtual machines that may be running in parallel depending on how memory is used by the guests.
At this time, memory ballooning is only supported through VBoxManage. Use the following command to increase or decrease the size of the memory balloon within a running virtual machine that has Guest Additions installed:
VBoxManage controlvm "VM name" guestmemoryballoon <n>

where "VM name" is the name or UUID of the virtual machine in question and <n> is the amount of memory to allocate from the guest in megabytes. See chapter 8.13, VBoxManage controlvm, page 140 for more information.
You can also set a default balloon that will automatically be requested from the VM every time after it has started up with the following command:
VBoxManage modifyvm "VM name" --guestmemoryballoon <n>

By default, no balloon memory is allocated. This is a VM setting, like other modifyvm settings, and therefore can only be set while the machine is shut down; see chapter 8.8, VBoxManage modifyvm, page 129.

4.9.2 Page Fusion
Whereas memory ballooning simply reduces the amount of RAM that is available to a VM, Page
Fusion works differently: it avoids memory duplication between several similar running VMs.
In a server environment running several similar VMs (e.g. with identical operating systems) on the same host, lots of memory pages are identical. VirtualBox’s Page Fusion technology, introduced with VirtualBox 3.2, is a novel technique to efﬁciently identify these identical memory pages and share them between multiple VMs.
Note: VirtualBox supports Page Fusion only on 64-bit hosts, and it is not supported on
Mac OS X hosts. Page Fusion currently works only with Windows guests (2000 and later). The more similar the VMs on a given host are, the more efﬁciently Page Fusion can reduce the amount of host memory that is in use. It therefore works best if all VMs on a host run identical operating systems (e.g. Windows XP Service Pack 2). Instead of having a complete copy of each operating system in each VM, Page Fusion identiﬁes the identical memory pages in use by these operating systems and eliminates the duplicates, sharing host memory between several machines
(“deduplication”). If a VM tries to modify a page that has been shared with other VMs, a new page is allocated again for that VM with a copy of the shared page (“copy on write”). All this is fully transparent to the virtual machine.
You may be familiar with this kind of memory overcommitment from other hypervisor products, which call this feature “page sharing” or “same page merging”. However, Page Fusion differs signiﬁcantly from those other solutions, whose approaches have several drawbacks:

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1. Traditional hypervisors scan all guest memory and compute checksums (hashes) for every single memory page. Then, they look for pages with identical hashes and compare the entire content of those pages; if two pages produce the same hash, it is very likely that the pages are identical in content. This, of course, can take rather long, especially if the system is not idling. As a result, the additional memory only becomes available after a signiﬁcant amount of time (this can be hours or even days!). Even worse, this kind of page sharing algorithm generally consumes signiﬁcant CPU resources and increases the virtualization overhead by 10-20%.
Page Fusion in VirtualBox uses logic in the VirtualBox Guest Additions to quickly identify memory cells that are most likely identical across VMs. It can therefore achieve most of the possible savings of page sharing almost immediately and with almost no overhead.
2. Page Fusion is also much less likely to be confused by identical memory that it will eliminate just to learn seconds later that the memory will now change and having to perform a highly expensive and often service-disrupting reallocation.
At this time, Page Fusion can only be controlled with VBoxManage, and only while a VM is shut down. To enable Page Fusion for a VM, use the following command:
VBoxManage modifyvm "VM name" --pagefusion on

You can observe Page Fusion operation using some metrics. RAM/VMM/Shared shows the total amount of fused pages, whereas the per-VM metric Guest/RAM/Usage/Shared will return the amount of fused memory for a given VM. Please refer to chapter 8.32, VBoxManage metrics, page
161 for information on how to query metrics.

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As the virtual machine will most probably expect to see a hard disk built into its virtual computer,
VirtualBox must be able to present “real” storage to the guest as a virtual hard disk. There are presently three methods in which to achieve this:
1. Most commonly, VirtualBox will use large image ﬁles on a real hard disk and present them to a guest as a virtual hard disk. This is described in chapter 5.2, Disk image ﬁles (VDI,
VMDK, VHD, HDD), page 84.
2. Alternatively, if you have iSCSI storage servers, you can attach such a server to VirtualBox as well; this is described in chapter 5.10, iSCSI servers, page 92.
3. Finally, as an advanced feature, you can allow a virtual machine to access one of your host disks directly; this advanced feature is described in chapter 9.9.1, Using a raw host hard disk from a guest, page 184.
Each such virtual storage device (image ﬁle, iSCSI target or physical hard disk) will need to be connected to the virtual hard disk controller that VirtualBox presents to a virtual machine. This is explained in the next section.

5.1 Hard disk controllers: IDE, SATA (AHCI), SCSI, SAS, USB
MSC
In a real PC, hard disks and CD/DVD drives are connected to a device called hard disk controller which drives hard disk operation and data transfers. VirtualBox can emulate the ﬁve most common types of hard disk controllers typically found in today’s PCs: IDE, SATA (AHCI), SCSI, SAS and USB-based mass storage devices.1
• IDE (ATA) controllers are a backwards compatible yet very advanced extension of the disk controller in the IBM PC/AT (1984). Initially, this interface worked only with hard disks, but was later extended to also support CD-ROM drives and other types of removable media.
In physical PCs, this standard uses ﬂat ribbon parallel cables with 40 or 80 wires. Each such cable can connect two devices to a controller, which have traditionally been called “master” and “slave”. Typical PCs had two connectors for such cables; as a result, support for up to four IDE devices was most common.
In VirtualBox, each virtual machine may have one IDE contoller enabled, which gives you up to four virtual storage devices that you can attach to the machine. (By default, one of these four – the secondary master – is preconﬁgured to be the machine’s virtual CD/DVD drive, but this can be changed.2 )
So even if your guest operating system has no support for SCSI or SATA devices, it should always be able to see an IDE controller.
1 SATA

support was added with VirtualBox 1.6; experimental SCSI support was added with 2.1 and fully implemented with 2.2. Generally, storage attachments were made much more ﬂexible with VirtualBox 3.1; see below. Support for the LSI Logic SAS controller was added with VirtualBox 3.2; USB mass storage devices are supported since VirtualBox
5.0.
2 The assignment of the machine’s CD/DVD drive to the secondary master was ﬁxed before VirtualBox 3.1; it is now changeable, and the drive can be at other slots of the IDE controller, and there can be more than one such drive.

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You can also select which exact type of IDE controller hardware VirtualBox should present to the virtual machine (PIIX3, PIIX4 or ICH6). This makes no difference in terms of performance, but if you import a virtual machine from another virtualization product, the operating system in that machine may expect a particular controller type and crash if it isn’t found.
After you have created a new virtual machine with the “New Virtual Machine” wizard of the graphical user interface, you will typically see one IDE controller in the machine’s “Storage” settings where the virtual CD/DVD drive will be attached to one of the four ports of this controller. • Serial ATA (SATA) is a newer standard introduced in 2003. Compared to IDE, it supports both much higher speeds and more devices per controller. Also, with physical hardware, devices can be added and removed while the system is running. The standard interface for
SATA controllers is called Advanced Host Controller Interface (AHCI).
Like a real SATA controller, VirtualBox’s virtual SATA controller operates faster and also consumes fewer CPU resources than the virtual IDE controller. Also, this allows you to connect up to 30 virtual hard disks to one machine instead of just three, as with the VirtualBox
IDE controller (with the DVD drive already attached).
For this reason, starting with version 3.2 and depending on the selected guest operating system, VirtualBox uses SATA as the default for newly created virtual machines. One virtual
SATA controller is created by default, and the default disk that is created with a new VM is attached to this controller.
Warning: The entire SATA controller and the virtual disks attached to it (including those in IDE compatibility mode) will not be seen by operating systems that do not have device support for AHCI. In particular, there is no support for AHCI in Windows before Windows Vista, so Windows XP (even SP3) will not see such disks unless you install additional drivers. It is possible to switch from IDE to SATA after installation by installing the SATA drivers and changing the controller type in the VM settings dialog.a a VirtualBox

recommends the Intel Matrix Storage drivers which can be downloaded from http://

downloadcenter.intel.com/Product_Filter.aspx?ProductID=2101.

To add a SATA controller to a machine for which it has not been enabled by default (either because it was created by an earlier version of VirtualBox, or because SATA is not supported by default by the selected guest operating system), go to the “Storage” page of the machine’s settings dialog, click on the “Add Controller” button under the “Storage Tree” box and then select “Add SATA Controller”. After this, the additional controller will appear as a separate PCI device in the virtual machine, and you can add virtual disks to it.
To change the IDE compatibility mode settings for the SATA controller, please see chapter
8.19, VBoxManage storagectl, page 146.
• SCSI is another established industry standard, standing for “Small Computer System Interface”. SCSI was standardized as early as 1986 as a generic interface for data transfer between all kinds of devices, including storage devices. Today SCSI is still used for connecting hard disks and tape devices, but it has mostly been displaced in commodity hardware.
It is still in common use in high-performance workstations and servers.
Primarily for compatibility with other virtualization software, VirtualBox optionally supports LSI Logic and BusLogic SCSI controllers, to each of which up to 15 virtual hard disks can be attached.
To enable a SCSI controller, on the “Storage” page of a virtual machine’s settings dialog, click on the “Add Controller” button under the “Storage Tree” box and then select “Add

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SCSI Controller”. After this, the additional controller will appear as a separate PCI device in the virtual machine.
Warning: As with the other controller types, a SCSI controller will only be seen by operating systems with device support for it. Windows 2003 and later ships with drivers for the LSI Logic controller, while Windows NT 4.0 and Windows 2000 ships with drivers for the BusLogic controller. Windows XP ships with drivers for neither.

• Serial Attached SCSI (SAS) is another bus standard which uses the SCSI command set. As opposed to SCSI, however, with physical devices, serial cables are used instead of parallel ones, which simpliﬁes physical device connections. In some ways, therefore, SAS is to SCSI what SATA is to IDE: it allows for more reliable and faster connections.
To support high-end guests which require SAS controllers, VirtualBox emulates a LSI Logic
SAS controller, which can be enabled much the same way as a SCSI controller. At this time, up to eight devices can be connected to the SAS controller.
Warning: As with SATA, the SAS controller will only be seen by operating systems with device support for it. In particular, there is no support for SAS in Windows before
Windows Vista, so Windows XP (even SP3) will not see such disks unless you install additional drivers.

• The USB mass storage device class is a standard to connect external storage devices like hard disksor ﬂash drives to a host through USB. All major operating systems support these devices for a long time and ship generic drivers making third-party drivers superﬂuous. In particular legacy operating systems without support for SATA controllers may beneﬁt from
USB mass storage devices.
The virtual USB storage controller offered by VirtualBox works different than the other storage controller types: When storage controllers appear as a single PCI device to the guest with multiple disks attached to it, the USB-based storage controller does not appear as virtual storage controller. Each disk attached to the controller appears as a dedicated
USB device to the guest.
Warning: Booting from drives attached via USB is not supported as the BIOS lacks USB support. In summary, VirtualBox gives you the following categories of virtual storage slots:
1. four slots attached to the traditional IDE controller, which are always present (one of which typically is a virtual CD/DVD drive);
2. 30 slots attached to the SATA controller, if enabled and supported by the guest operating system; 3. 15 slots attached to the SCSI controller, if enabled and supported by the guest operating system; 4. eight slots attached to the SAS controller, if enabled and supported by the guest operating system. 83

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5. eight slots attached to the virtual USB controller, if enabled and supported by the guest operating system.
Given this large choice of storage controllers, you may ask yourself which one to choose. In general, you should avoid IDE unless it is the only controller supported by your guest. Whether you use SATA, SCSI or SAS does not make any real difference. The variety of controllers is only supplied for VirtualBox for compatibility with existing hardware and other hypervisors.

5.2 Disk image ﬁles (VDI, VMDK, VHD, HDD)
Disk image ﬁles reside on the host system and are seen by the guest systems as hard disks of a certain geometry. When a guest operating system reads from or writes to a hard disk, VirtualBox redirects the request to the image ﬁle.
Like a physical disk, a virtual disk has a size (capacity), which must be speciﬁed when the image ﬁle is created. As opposed to a physical disk however, VirtualBox allows you to expand an image ﬁle after creation, even if it has data already; see chapter 8.23, VBoxManage modifyhd, page 148 for details.3
VirtualBox supports four variants of disk image ﬁles:
• Normally, VirtualBox uses its own container format for guest hard disks – Virtual Disk
Image (VDI) ﬁles. In particular, this format will be used when you create a new virtual machine with a new disk.
• VirtualBox also fully supports the popular and open VMDK container format that is used by many other virtualization products, in particular, by VMware.4
• VirtualBox also fully supports the VHD format used by Microsoft.
• Image ﬁles of Parallels version 2 (HDD format) are also supported.5 For lack of documentation of the format, newer formats (3 and 4) are not supported. You can however convert such image ﬁles to version 2 format using tools provided by Parallels.
Irrespective of the disk capacity and format, as brieﬂy mentioned in chapter 1.7, Creating your ﬁrst virtual machine, page 17, there are two options of how to create a disk image: ﬁxed-size or dynamically allocated.
• If you create a ﬁxed-size image, an image ﬁle will be created on your host system which has roughly the same size as the virtual disk’s capacity. So, for a 10G disk, you will have a 10G ﬁle. Note that the creation of a ﬁxed-size image can take a long time depending on the size of the image and the write performance of your hard disk.
• For more ﬂexible storage management, use a dynamically allocated image. This will initially be very small and not occupy any space for unused virtual disk sectors, but will grow every time a disk sector is written to for the ﬁrst time, until the drive reaches the maximum capacity chosen when the drive was created. While this format takes less space initially, the fact that VirtualBox needs to expand the image ﬁle consumes additional computing resources, so until the disk ﬁle size has stabilized, write operations may be slower than with ﬁxed size disks. However, after a time the rate of growth will slow and the average penalty for write operations will be negligible.

3 Image

resizing was added with VirtualBox 4.0. support for VMDK was added with VirtualBox 1.4; since version 2.1, VirtualBox supports VMDK fully, meaning that you can create snapshots and use all the other advanced features described above for VDI images with VMDK also. 5 Support was added with VirtualBox 3.1.
4 Initial

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5.3 The Virtual Media Manager
VirtualBox keeps track of all the hard disk, CD/DVD-ROM and ﬂoppy disk images which are in use by virtual machines. These are often referred to as “known media” and come from two sources: • all media currently attached to virtual machines;
• “registered” media for compatibility with VirtualBox versions older than version 4.0. For details about how media registration has changed with version 4.0, please refer to chapter
10.1, Where VirtualBox stores its ﬁles, page 215.
The known media can be viewed and changed in the Virtual Media Manager, which you can access from the “File” menu in the VirtualBox main window:

The known media are conveniently grouped in three tabs for the three possible formats. These formats are:
• Hard disk images, either in VirtualBox’s own Virtual Disk Image (VDI) format or in the third-party formats listed in the previous chapter;
• CD/DVD images in standard ISO format;
• ﬂoppy images in standard RAW format.
As you can see in the screenshot above, for each image, the Virtual Media Manager shows you the full path of the image ﬁle and other information, such as the virtual machine the image is currently attached to, if any.
The Virtual Media Manager allows you to
• remove an image from the registry (and optionally delete the image ﬁle when doing so);
• “release” an image, that is, detach it from a virtual machine if it is currently attached to one as a virtual hard disk.

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Starting with version 4.0, to create new disk images, please use the “Storage” page in a virtual machine’s settings dialog because disk images are now by default stored in each machine’s own folder. Hard disk image ﬁles can be copied onto other host systems and imported into virtual machines there, although certain guest systems (notably Windows 2000 and XP) will require that the new virtual machine be set up in a similar way to the old one.
Note: Do not simply make copies of virtual disk images. If you import such a second copy into a virtual machine, VirtualBox will complain with an error, since VirtualBox assigns a unique identiﬁer (UUID) to each disk image to make sure it is only used once.
See chapter 5.6, Cloning disk images, page 90 for instructions on this matter. Also, if you want to copy a virtual machine to another system, VirtualBox has an import/export facility that might be better suited for your needs; see chapter 1.14, Importing and exporting virtual machines, page 30.

5.4 Special image write modes
For each virtual disk image supported by VirtualBox, you can determine separately how it should be affected by write operations from a virtual machine and snapshot operations. This applies to all of the aforementioned image formats (VDI, VMDK, VHD or HDD) and irrespective of whether an image is ﬁxed-size or dynamically allocated.
By default, images are in “normal” mode. To mark an existing image with one of the nonstandard modes listed below, use VBoxManage modifyhd; see chapter 8.23, VBoxManage modifyhd, page 148. Alternatively, use VBoxManage to attach the image to a VM and use the --mtype argument; see chapter 8.18, VBoxManage storageattach, page 144.
1. With normal images (the default setting), there are no restrictions on how guests can read from and write to the disk.
When you take a snapshot of your virtual machine as described in chapter 1.10, Snapshots, page 25, the state of such a “normal hard disk” will be recorded together with the snapshot, and when reverting to the snapshot, its state will be fully reset.
(Technically, strictly speaking, the image ﬁle itself is not “reset”. Instead, when a snapshot is taken, VirtualBox “freezes” the image ﬁle and no longer writes to it. For the write operations from the VM, a second, “differencing” image ﬁle is created which receives only the changes to the original image; see the next section for details.)
While you can attach the same “normal” image to more than one virtual machine, only one of these virtual machines attached to the same image ﬁle can be executed simultaneously, as otherwise there would be conﬂicts if several machines write to the same image ﬁle.6
2. By contrast, write-through hard disks are completely unaffected by snapshots: their state is not saved when a snapshot is taken, and not restored when a snapshot is restored.
3. Shareable hard disks are a variant of write-through hard disks. In principle they behave exactly the same, i.e. their state is not saved when a snapshot is taken, and not restored when a snapshot is restored. The difference only shows if you attach such disks to several
VMs. Shareable disks may be attached to several VMs which may run concurrently. This makes them suitable for use by cluster ﬁlesystems between VMs and similar applications which are explicitly prepared to access a disk concurrently. Only ﬁxed size images can be used in this way, and dynamically allocated images are rejected.
6 This

restriction is more lenient now than it was before VirtualBox 2.2. Previously, each “normal” disk image could only be attached to one single machine. Now it can be attached to more than one machine so long as only one of these machines is running.

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Warning: This is an expert feature, and misuse can lead to data loss – regular ﬁlesystems are not prepared to handle simultaneous changes by several parties.

4. Next, immutable images only remember write accesses temporarily while the virtual machine is running; all changes are lost when the virtual machine is powered on the next time. As a result, as opposed to “normal” images, the same immutable image can be used with several virtual machines without restrictions.
Creating an immutable image makes little sense since it would be initially empty and lose its contents with every machine restart (unless you really want to have a disk that is always unformatted when the machine starts up). As a result, normally, you would ﬁrst create a
“normal” image and then, when you deem its contents useful, later mark it immutable.
If you take a snapshot of a machine with immutable images, then on every machine powerup, those images are reset to the state of the last (current) snapshot (instead of the state of the original immutable image).
Note: As a special exception, immutable images are not reset if they are attached to a machine whose last snapshot was taken while the machine was running (a so-called
“online” snapshot). As a result, if the machine’s current snapshot is such an “online” snapshot, its immutable images behave exactly like the “normal” images described previously. To re-enable the automatic resetting of such images, delete the current snapshot of the machine.
Again, technically, VirtualBox never writes to an immutable image directly at all. All write operations from the machine will be directed to a differencing image; the next time the
VM is powered on, the differencing image is reset so that every time the VM starts, its immutable images have exactly the same content.7 The differencing image is only reset when the machine is powered on from within VirtualBox, not when you reboot by requesting a reboot from within the machine. This is also why immutable images behave as described above when snapshots are also present, which use differencing images as well.
If the automatic discarding of the differencing image on VM startup does not ﬁt your needs, you can turn it off using the autoreset parameter of VBoxManage modifyhd; see chapter
8.23, VBoxManage modifyhd, page 148 for details.
5. An image in multiattach mode can be attached to more than one virtual machine at the same time, even if these machines are running simultaneously. For each virtual machine to which such an image is attached, a differencing image is created. As a result, data that is written to such a virtual disk by one machine is not seen by the other machines to which the image is attached; each machine creates its own write history of the multiattach image.
Technically, a “multiattach” image behaves identically to an “immutable” image except the differencing image is not reset every time the machine starts.
This mode is useful for sharing ﬁles which are almost never written, for instance picture galleries, where every guest changes only a small amount of data and the majority of the disk content remains unchanged. The modiﬁed blocks are stored in differencing images which remain reletively small and the shared content is stored only once at the host.
6. Finally, the read-only image is used automatically for CD/DVD images, since CDs/DVDs can never be written to.
7 This

behavior also changed with VirtualBox 2.2. Previously, the differencing images were discarded when the machine session ended; now they are discarded every time the machine is powered on.

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To illustrate the differences between the various types with respect to snapshots: Assume you have installed your guest operating system in your VM, and you have taken a snapshot.
Imagine you have accidentally infected your VM with a virus and would like to go back to the snapshot. With a normal hard disk image, you simply restore the snapshot, and the earlier state of your hard disk image will be restored as well (and your virus infection will be undone).
With an immutable hard disk, all it takes is to shut down and power on your VM, and the virus infection will be discarded. With a write-through image however, you cannot easily undo the virus infection by means of virtualization, but will have to disinfect your virtual machine like a real computer.
Still, you might ﬁnd write-through images useful if you want to preserve critical data irrespective of snapshots, and since you can attach more than one image to a VM, you may want to have one immutable for the operating system and one write-through for your data ﬁles.

5.5 Differencing images
The previous section hinted at differencing images and how they are used with snapshots, immutable images and multiple disk attachments. For the inquisitive VirtualBox user, this section describes in more detail how they work.
A differencing image is a special disk image that only holds the differences to another image.
A differencing image by itself is useless, it must always refer to another image. The differencing image is then typically referred to as a “child”, which holds the differences to its “parent”.
When a differencing image is active, it receives all write operations from the virtual machine instead of its parent. The differencing image only contains the sectors of the virtual hard disk that have changed since the differencing image was created. When the machine reads a sector from such a virtual hard disk, it looks into the differencing image ﬁrst. If the sector is present, it is returned from there; if not, VirtualBox looks into the parent. In other words, the parent becomes “read-only”; it is never written to again, but it is read from if a sector has not changed.
Differencing images can be chained. If another differencing image is created for a virtual disk that already has a differencing image, then it becomes a “grandchild” of the original parent.
The ﬁrst differencing image then becomes read-only as well, and write operations only go to the second-level differencing image. When reading from the virtual disk, VirtualBox needs to look into the second differencing image ﬁrst, then into the ﬁrst if the sector was not found, and then into the original image.
There can be an unlimited number of differencing images, and each image can have more than one child. As a result, the differencing images can form a complex tree with parents, “siblings” and children, depending on how complex your machine conﬁguration is. Write operations always go to the one “active” differencing image that is attached to the machine, and for read operations,
VirtualBox may need to look up all the parents in the chain until the sector in question is found.
You can look at such a tree in the Virtual Media Manager:

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In all of these situations, from the point of view of the virtual machine, the virtual hard disk behaves like any other disk. While the virtual machine is running, there is a slight run-time I/O overhead because VirtualBox might need to look up sectors several times. This is not noticeable however since the tables with sector information are always kept in memory and can be looked up quickly.
Differencing images are used in the following situations:
1. Snapshots. When you create a snapshot, as explained in the previous section, VirtualBox
“freezes” the images attached to the virtual machine and creates differencing images for each of them (to be precise: one for each image that is not in “write-through” mode). From the point of view of the virtual machine, the virtual disks continue to operate before, but all write operations go into the differencing images. Each time you create another snapshot, for each hard disk attachment, another differencing image is created and attached, forming a chain or tree.
In the above screenshot, you see that the original disk image is now attached to a snapshot, representing the state of the disk when the snapshot was taken.
If you now restore a snapshot – that is, if you want to go back to the exact machine state that was stored in the snapshot –, the following happens:
a) VirtualBox copies the virtual machine settings that were copied into the snapshot back to the virtual machine. As a result, if you have made changes to the machine conﬁguration since taking the snapshot, they are undone.
b) If the snapshot was taken while the machine was running, it contains a saved machine state, and that state is restored as well; after restoring the snapshot, the machine will then be in “Saved” state and resume execution from there when it is next started.
Otherwise the machine will be in “Powered Off” state and do a full boot.
c) For each disk image attached to the machine, the differencing image holding all the write operations since the current snapshot was taken is thrown away, and the original parent image is made active again. (If you restored the “root” snapshot, then this will be the root disk image for each attachment; otherwise, some other differencing image descended from it.) This effectively restores the old machine state.

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If you later delete a snapshot in order to free disk space, for each disk attachment, one of the differencing images becomes obsolete. In this case, the differencing image of the disk attachment cannot simply be deleted. Instead, VirtualBox needs to look at each sector of the differencing image and needs to copy it back into its parent; this is called “merging” images and can be a potentially lengthy process, depending on how large the differencing image is. It can also temporarily need a considerable amount of extra disk space, before the differencing image obsoleted by the merge operation is deleted.
2. Immutable images. When an image is switched to “immutable” mode, a differencing image is created as well. As with snapshots, the parent image then becomes read-only, and the differencing image receives all the write operations. Every time the virtual machine is started, all the immutable images which are attached to it have their respective differencing image thrown away, effectively resetting the virtual machine’s virtual disk with every restart. 5.6 Cloning disk images
You can duplicate hard disk image ﬁles on the same host to quickly produce a second virtual machine with the same operating system setup. However, you should only make copies of virtual disk images using the utility supplied with VirtualBox; see chapter 8.24, VBoxManage clonehd, page 149. This is because VirtualBox assigns a unique identity number (UUID) to each disk image, which is also stored inside the image, and VirtualBox will refuse to work with two images that use the same number. If you do accidentally try to reimport a disk image which you copied normally, you can make a second copy using VirtualBox’s utility and import that instead.
Note that newer Linux distributions identify the boot hard disk from the ID of the drive. The
ID VirtualBox reports for a drive is determined from the UUID of the virtual disk image. So if you clone a disk image and try to boot the copied image the guest might not be able to determine its own boot disk as the UUID changed. In this case you have to adapt the disk ID in your boot loader script (for example /boot/grub/menu.lst). The disk ID looks like this: scsi-SATA_VBOX_HARDDISK_VB5cfdb1e2-c251e503 The ID for the copied image can be determined with hdparm -i /dev/sda

5.7 Host I/O caching
Starting with version 3.2, VirtualBox can optionally disable the I/O caching that the host operating system would otherwise perform on disk image ﬁles.
Traditionally, VirtualBox has opened disk image ﬁles as normal ﬁles, which results in them being cached by the host operating system like any other ﬁle. The main advantage of this is speed: when the guest OS writes to disk and the host OS cache uses delayed writing, the write operation can be reported as completed to the guest OS quickly while the host OS can perform the operation asynchronously. Also, when you start a VM a second time and have enough memory available for the OS to use for caching, large parts of the virtual disk may be in system memory, and the VM can access the data much faster.
Note that this applies only to image ﬁles; buffering never occurred for virtual disks residing on remote iSCSI storage, which is the more common scenario in enterprise-class setups (see chapter
5.10, iSCSI servers, page 92).
While buffering is a useful default setting for virtualizating a few machines on a desktop computer, there are some disadvantages to this approach:

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1. Delayed writing through the host OS cache is less secure. When the guest OS writes data, it considers the data written even though it has not yet arrived on a physical disk. If for some reason the write does not happen (power failure, host crash), the likelihood of data loss increases.
2. Disk image ﬁles tend to be very large. Caching them can therefore quickly use up the entire host OS cache. Depending on the efﬁciency of the host OS caching, this may slow down the host immensely, especially if several VMs run at the same time. For example, on Linux hosts, host caching may result in Linux delaying all writes until the host cache is nearly full and then writing out all these changes at once, possibly stalling VM execution for minutes.
This can result in I/O errors in the guest as I/O requests time out there.
3. Physical memory is often wasted as guest operating systems typically have their own I/O caches, which may result in the data being cached twice (in both the guest and the host caches) for little effect.
If you decide to disable host I/O caching for the above reasons, VirtualBox uses its own small cache to buffer writes, but no read caching since this is typically already performed by the guest
OS. In addition, VirtualBox fully supports asynchronous I/O for its virtual SATA, SCSI and SAS controllers through multiple I/O threads.
Since asynchronous I/O is not supported by IDE controllers, for performance reasons, you may want to leave host caching enabled for your VM’s virtual IDE controllers.
For this reason, VirtualBox allows you to conﬁgure whether the host I/O cache is used for each
I/O controller separately. Either uncheck the “Use host I/O cache” box in the “Storage” settings for a given virtual storage controller, or use the following VBoxManage command to disable the host I/O cache for a virtual storage controller:
VBoxManage storagectl "VM name" --name <controllername> --hostiocache off

See chapter 8.19, VBoxManage storagectl, page 146 for details.
For the above reasons also, VirtualBox now uses SATA controllers by default for new virtual machines. 5.8 Limiting bandwidth for disk images
Starting with version 4.0, VirtualBox allows for limiting the maximum bandwidth used for asynchronous I/O. Additionally it supports sharing limits through bandwidth groups for several images. It is possible to have more than one such limit.
Limits are conﬁgured through VBoxManage. The example below creates a bandwidth group named “Limit”, sets the limit to 20 MB/s and assigns the group to the attached disks of the VM:
VBoxManage bandwidthctl "VM name" add Limit --type disk --limit 20M
VBoxManage storageattach "VM name" --storagectl "SATA" --port 0 --device 0 --type hdd
--medium disk1.vdi --bandwidthgroup Limit
VBoxManage storageattach "VM name" --storagectl "SATA" --port 1 --device 0 --type hdd
--medium disk2.vdi --bandwidthgroup Limit

All disks in a group share the bandwidth limit, meaning that in the example above the bandwidth of both images combined can never exceed 20 MB/s. However, if one disk doesn’t require bandwidth the other can use the remaining bandwidth of its group.
The limits for each group can be changed while the VM is running, with changes being picked up immediately. The example below changes the limit for the group created in the example above to 10 MB/s:
VBoxManage bandwidthctl "VM name" set Limit --limit 10M

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5.9 CD/DVD support
The virtual CD/DVD drive(s) by default support only reading. The medium conﬁguration is changeable at runtime. You can select between three options to provide the medium data:
• Host Drive deﬁnes that the guest can read from the medium in the host drive.
• Image ﬁle (typically an ISO ﬁle) gives the guest read-only access to the data in the image.
• Empty stands for a drive without an inserted medium.
Changing between the above, or changing a medium in the host drive that is accessed by a machine, or changing an image ﬁle will signal a medium change to the guest operating system, which can then react to the change (e.g. by starting an installation program).
Medium changes can be prevented by the guest, and VirtualBox reﬂects that by locking the host drive if appropriate. You can force a medium removal in such situations via the VirtualBox
GUI or the VBoxManage command line tool. Effectively this is the equivalent of the emergency eject which many CD/DVD drives provide, with all associated side effects: the guest OS can issue error messages, just like on real hardware, and guest applications may misbehave. Use this with caution. Note: The identiﬁcation string of the drive provided to the guest (which, in the guest, would be displayed by conﬁguration tools such as the Windows Device Manager) is always “VBOX CD-ROM”, irrespective of the current conﬁguration of the virtual drive.
This is to prevent hardware detection from being triggered in the guest operating system every time the conﬁguration is changed.
The standard CD/DVD emulation allows for reading standard data CD and DVD formats only.
As an experimental feature, for additional capabilities, it is possible to give the guest direct access to the CD/DVD host drive by enabling “passthrough” mode. Depending on the host hardware, this may enable three things to work, potentially:
• CD/DVD writing from within the guest, if the host DVD drive is a CD/DVD writer;
• playing audio CDs;
• playing encrypted DVDs.
There is a “Passthrough” checkbox in the GUI dialog for conﬁguring the media attached to a storage controller, or you can use the --passthrough option with VBoxManage storageattach; see chapter 8.18, VBoxManage storageattach, page 144 for details.
Even if pass-through is enabled, unsafe commands, such as updating the drive ﬁrmware, will be blocked. Video CD formats are never supported, not even in passthrough mode, and cannot be played from a virtual machine.
On Solaris hosts, pass-through requires running VirtualBox with real root permissions due to security measures enforced by the host.

5.10 iSCSI servers iSCSI stands for “Internet SCSI” and is a standard that allows for using the SCSI protocol over
Internet (TCP/IP) connections. Especially with the advent of Gigabit Ethernet, it has become affordable to attach iSCSI storage servers simply as remote hard disks to a computer network. In iSCSI terminology, the server providing storage resources is called an “iSCSI target”, while the client connecting to the server and accessing its resources is called “iSCSI initiator”.

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VirtualBox can transparently present iSCSI remote storage to a virtual machine as a virtual hard disk. The guest operating system will not see any difference between a virtual disk image
(VDI ﬁle) and an iSCSI target. To achieve this, VirtualBox has an integrated iSCSI initiator.
VirtualBox’s iSCSI support has been developed according to the iSCSI standard and should work with all standard-conforming iSCSI targets. To use an iSCSI target with VirtualBox, you must use the command line; see chapter 8.18, VBoxManage storageattach, page 144.

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6 Virtual networking
As brieﬂy mentioned in chapter 3.8, Network settings, page 53, VirtualBox provides up to eight virtual PCI Ethernet cards for each virtual machine. For each such card, you can individually select 1. the hardware that will be virtualized as well as
2. the virtualization mode that the virtual card will be operating in with respect to your physical networking hardware on the host.
Four of the network cards can be conﬁgured in the “Network” section of the settings dialog in the graphical user interface of VirtualBox. You can conﬁgure all eight network cards on the command line via VBoxManage modifyvm; see chapter 8.8, VBoxManage modifyvm, page 129.
This chapter explains the various networking settings in more detail.

6.1 Virtual networking hardware
For each card, you can individually select what kind of hardware will be presented to the virtual machine. VirtualBox can virtualize the following six types of networking hardware:
• AMD PCNet PCI II (Am79C970A);
• AMD PCNet FAST III (Am79C973, the default);
• Intel PRO/1000 MT Desktop (82540EM);
• Intel PRO/1000 T Server (82543GC);
• Intel PRO/1000 MT Server (82545EM);
• Paravirtualized network adapter (virtio-net).
The PCNet FAST III is the default because it is supported by nearly all operating systems out of the box, as well as the GNU GRUB boot manager. As an exception, the Intel PRO/1000 family adapters are chosen for some guest operating system types that no longer ship with drivers for the PCNet card, such as Windows Vista.
The Intel PRO/1000 MT Desktop type works with Windows Vista and later versions. The T
Server variant of the Intel PRO/1000 card is recognized by Windows XP guests without additional driver installation. The MT Server variant facilitates OVF imports from other platforms.
The “Paravirtualized network adapter (virtio-net)“ is special. If you select this, then
VirtualBox does not virtualize common networking hardware (that is supported by common guest operating systems out of the box). Instead, VirtualBox then expects a special software interface for virtualized environments to be provided by the guest, thus avoiding the complexity of emulating networking hardware and improving network performance. Starting with version
3.1, VirtualBox provides support for the industry-standard “virtio” networking drivers, which are part of the open-source KVM project.
The “virtio” networking drivers are available for the following guest operating systems:
• Linux kernels version 2.6.25 or later can be conﬁgured to provide virtio support; some distributions also back-ported virtio to older kernels.

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• For Windows 2000, XP and Vista, virtio drivers can be downloaded and installed from the
KVM project web page.1
VirtualBox also has limited support for so-called jumbo frames, i.e. networking packets with more than 1500 bytes of data, provided that you use the Intel card virtualization and bridged networking. In other words, jumbo frames are not supported with the AMD networking devices; in those cases, jumbo packets will silently be dropped for both the transmit and the receive direction. Guest operating systems trying to use this feature will observe this as a packet loss, which may lead to unexpected application behavior in the guest. This does not cause problems with guest operating systems in their default conﬁguration, as jumbo frames need to be explicitly enabled. 6.2 Introduction to networking modes
Each of the eight networking adapters can be separately conﬁgured to operate in one of the following modes:
Not attached In this mode, VirtualBox reports to the guest that a network card is present, but that there is no connection – as if no Ethernet cable was plugged into the card. This way it is possible to “pull” the virtual Ethernet cable and disrupt the connection, which can be useful to inform a guest operating system that no network connection is available and enforce a reconﬁguration.
Network Address Translation (NAT) If all you want is to browse the Web, download ﬁles and view e-mail inside the guest, then this default mode should be sufﬁcient for you, and you can safely skip the rest of this section. Please note that there are certain limitations when using Windows ﬁle sharing (see chapter 6.3.3, NAT limitations, page 97 for details).
NAT Network The NAT network is a new NAT ﬂavour introduced in VirtualBox 4.3. See chapter
6.4, Network Address Translation Service (experimental), page 98 for details.
Bridged networking This is for more advanced networking needs such as network simulations and running servers in a guest. When enabled, VirtualBox connects to one of your installed network cards and exchanges network packets directly, circumventing your host operating system’s network stack.
Internal networking This can be used to create a different kind of software-based network which is visible to selected virtual machines, but not to applications running on the host or to the outside world.
Host-only networking This can be used to create a network containing the host and a set of virtual machines, without the need for the host’s physical network interface. Instead, a virtual network interface (similar to a loopback interface) is created on the host, providing connectivity among virtual machines and the host.
Generic networking Rarely used modes share the same generic network interface, by allowing the user to select a driver which can be included with VirtualBox or be distributed in an extension pack.
At the moment there are potentially two available sub-modes:
UDP Tunnel This can be used to interconnect virtual machines running on different hosts directly, easily and transparently, over existing network infrastructure.
VDE (Virtual Distributed Ethernet) networking This option can be used to connect to a
Virtual Distributed Ethernet switch on a Linux or a FreeBSD host. At the moment this needs compiling VirtualBox from sources, as the Oracle packages do not include it.
1 http://www.linux-kvm.org/page/WindowsGuestDrivers.

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The following sections describe the available network modes in more detail.

6.3 Network Address Translation (NAT)
Network Address Translation (NAT) is the simplest way of accessing an external network from a virtual machine. Usually, it does not require any conﬁguration on the host network and guest system. For this reason, it is the default networking mode in VirtualBox.
A virtual machine with NAT enabled acts much like a real computer that connects to the
Internet through a router. The “router”, in this case, is the VirtualBox networking engine, which maps trafﬁc from and to the virtual machine transparently. In VirtualBox this router is placed between each virtual machine and the host. This separation maximizes security since by default virtual machines cannot talk to each other.
The disadvantage of NAT mode is that, much like a private network behind a router, the virtual machine is invisible and unreachable from the outside internet; you cannot run a server this way unless you set up port forwarding (described below).
The network frames sent out by the guest operating system are received by VirtualBox’s NAT engine, which extracts the TCP/IP data and resends it using the host operating system. To an application on the host, or to another computer on the same network as the host, it looks like the data was sent by the VirtualBox application on the host, using an IP address belonging to the host. VirtualBox listens for replies to the packages sent, and repacks and resends them to the guest machine on its private network.
The virtual machine receives its network address and conﬁguration on the private network from a DHCP server integrated into VirtualBox. The IP address thus assigned to the virtual machine is usually on a completely different network than the host. As more than one card of a virtual machine can be set up to use NAT, the ﬁrst card is connected to the private network
10.0.2.0, the second card to the network 10.0.3.0 and so on. If you need to change the guestassigned IP range for some reason, please refer to chapter 9.11, Fine-tuning the VirtualBox NAT engine, page 187.

6.3.1 Conﬁguring port forwarding with NAT
As the virtual machine is connected to a private network internal to VirtualBox and invisible to the host, network services on the guest are not accessible to the host machine or to other computers on the same network. However, like a physical router, VirtualBox can make selected services available to the world outside the guest through port forwarding. This means that
VirtualBox listens to certain ports on the host and resends all packets which arrive there to the guest, on the same or a different port.
To an application on the host or other physical (or virtual) machines on the network, it looks as though the service being proxied is actually running on the host. This also means that you cannot run the same service on the same ports on the host. However, you still gain the advantages of running the service in a virtual machine – for example, services on the host machine or on other virtual machines cannot be compromised or crashed by a vulnerability or a bug in the service, and the service can run in a different operating system than the host system.
To conﬁgure Port Forwarding you can use the graphical Port Forwarding editor which can be found in the Network Settings dialog for Network Adaptors conﬁgured to use NAT. Here you can map host ports to guest ports to allow network trafﬁc to be routed to a speciﬁc port in the guest.
Alternatively command line tool VBoxManage could be used; for details, please refer to chapter
8.8, VBoxManage modifyvm, page 129.
You will need to know which ports on the guest the service uses and to decide which ports to use on the host (often but not always you will want to use the same ports on the guest and on the host). You can use any ports on the host which are not already in use by a service. For example, to set up incoming NAT connections to an ssh server in the guest, use the following command: 96

6 Virtual networking
VBoxManage modifyvm "VM name" --natpf1 "guestssh,tcp,,2222,,22"

With the above example, all TCP trafﬁc arriving on port 2222 on any host interface will be forwarded to port 22 in the guest. The protocol name tcp is a mandatory attribute deﬁning which protocol should be used for forwarding (udp could also be used). The name guestssh is purely descriptive and will be auto-generated if omitted. The number after --natpf denotes the network card, like in other parts of VBoxManage.
To remove this forwarding rule again, use the following command:
VBoxManage modifyvm "VM name" --natpf1 delete "guestssh"

If for some reason the guest uses a static assigned IP address not leased from the built-in DHCP server, it is required to specify the guest IP when registering the forwarding rule:
VBoxManage modifyvm "VM name" --natpf1 "guestssh,tcp,,2222,10.0.2.19,22"

This example is identical to the previous one, except that the NAT engine is being told that the guest can be found at the 10.0.2.19 address.
To forward all incoming trafﬁc from a speciﬁc host interface to the guest, specify the IP of that host interface like this:
VBoxManage modifyvm "VM name" --natpf1 "guestssh,tcp,127.0.0.1,2222,,22"

This forwards all TCP trafﬁc arriving on the localhost interface (127.0.0.1) via port 2222 to port
22 in the guest.
It is possible to conﬁgure incoming NAT connections while the VM is running, see chapter
8.13, VBoxManage controlvm, page 140.

6.3.2 PXE booting with NAT
PXE booting is now supported in NAT mode. The NAT DHCP server provides a boot ﬁle name of the form vmname.pxe if the directory TFTP exists in the directory where the user’s
VirtualBox.xml ﬁle is kept. It is the responsibility of the user to provide vmname.pxe.

6.3.3 NAT limitations
There are four limitations of NAT mode which users should be aware of:
ICMP protocol limitations: Some frequently used network debugging tools (e.g. ping or tracerouting) rely on the ICMP protocol for sending/receiving messages. While ICMP support has been improved with VirtualBox 2.1 (ping should now work), some other tools may not work reliably.
Receiving of UDP broadcasts is not reliable: The guest does not reliably receive broadcasts, since, in order to save resources, it only listens for a certain amount of time after the guest has sent UDP data on a particular port. As a consequence, NetBios name resolution based on broadcasts does not always work (but WINS always works). As a workaround, you can use the numeric IP of the desired server in the \\server\share notation.
Protocols such as GRE are unsupported: Protocols other than TCP and UDP are not supported. This means some VPN products (e.g. PPTP from Microsoft) cannot be used. There are other VPN products which use simply TCP and UDP.
Forwarding host ports < 1024 impossible: On Unix-based hosts (e.g. Linux, Solaris, Mac OS
X) it is not possible to bind to ports below 1024 from applications that are not run by root.
As a result, if you try to conﬁgure such a port forwarding, the VM will refuse to start.
These limitations normally don’t affect standard network use. But the presence of NAT has also subtle effects that may interfere with protocols that are normally working. One example is
NFS, where the server is often conﬁgured to refuse connections from non-privileged ports (i.e. ports not below 1024).

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6.4 Network Address Translation Service (experimental)
The Network Address Translation (NAT) service works in a similar way to a home router, grouping the systems using it into a network and preventing systems outside of this network from directly accessing systems inside it, but letting systems inside communicate with each other and with systems outside using TCP and UDP over IPv4 and IPv6.
A NAT service is attached to an internal network. Virtual machines which are to make use of it should be attached to that internal network. The name of internal network is chosen when the
NAT service is created and the internal network will be created if it does not already exist. An example command to create a NAT network is:
VBoxManage natnetwork add --netname natnet1 --network "192.168.15.0/24" --enable

Here, “natnet1” is the name of the internal network to be used and “192.168.15.0/24” is the network address and mask of the NAT service interface. By default in this static conﬁguration the gateway will be assigned the address 192.168.15.1 (the address following the interface address), though this is subject to change. To attach a DHCP server to the internal network, we modify the example as follows:
VBoxManage natnetwork add --netname natnet1 --network "192.168.15.0/24" --enable --dhcp on

or to add a DHCP server to the network after creation:
VBoxManage natnetwork modify --netname natnet1 --dhcp on

To disable it again, use:
VBoxManage natnetwork modify --netname natnet1 --dhcp off

DHCP server provides list of registered nameservers, but doesn’t map servers from 127/8 network. To start the NAT service, use the following command:
VBoxManage natnetwork start --netname natnet1

If the network has a DHCP server attached then it will start together with the NAT network service. VBoxManage natnetwork stop --netname natnet1

stops the NAT network service, together with DHCP server if any.
To delete the NAT network service use:
VBoxManage natnetwork remove --netname natnet1

This command does not remove the DHCP server if one is enabled on the internal network.
Port-forwarding is supported (using the “–port-forward-4” switch for IPv4 and “–port-forward6” for IPv6):
VBoxManage natnetwork modify --netname natnet1 --port-forward-4 "ssh:tcp:[]:1022:[192.168.15.5]:22"

This adds a port-forwarding rule from the host’s TCP 1022 port to the port 22 on the guest with IP address 192.168.15.5. Host port, guest port and guest IP are mandatory. To delete the rule, use:
VBoxManage natnetwork modify --netname natnet1 --port-forward-4 delete ssh

It’s possible to bind NAT service to speciﬁed interface:
VBoxManage setextradata global "NAT/win-nat-test-0/SourceIp4" 192.168.1.185

To see the list of registered NAT networks, use:
VBoxManage list natnetworks

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6.5 Bridged networking
With bridged networking, VirtualBox uses a device driver on your host system that ﬁlters data from your physical network adapter. This driver is therefore called a “net ﬁlter” driver. This allows VirtualBox to intercept data from the physical network and inject data into it, effectively creating a new network interface in software. When a guest is using such a new software interface, it looks to the host system as though the guest were physically connected to the interface using a network cable: the host can send data to the guest through that interface and receive data from it. This means that you can set up routing or bridging between the guest and the rest of your network.
For this to work, VirtualBox needs a device driver on your host system. The way bridged networking works has been completely rewritten with VirtualBox 2.0 and 2.1, depending on the host operating system. From the user perspective, the main difference is that complex conﬁguration is no longer necessary on any of the supported host operating systems.2
Note: Even though TAP is no longer necessary on Linux with bridged networking, you can still use TAP interfaces for certain advanced setups, since you can connect a VM to any host interface – which could also be a TAP interface.
To enable bridged networking, all you need to do is to open the Settings dialog of a virtual machine, go to the “Network” page and select “Bridged network” in the drop down list for the
“Attached to” ﬁeld. Finally, select desired host interface from the list at the bottom of the page, which contains the physical network interfaces of your systems. On a typical MacBook, for example, this will allow you to select between “en1: AirPort” (which is the wireless interface) and “en0: Ethernet”, which represents the interface with a network cable.
Note: Bridging to a wireless interface is done differently from bridging to a wired interface, because most wireless adapters do not support promiscuous mode. All trafﬁc has to use the MAC address of the host’s wireless adapter, and therefore VirtualBox needs to replace the source MAC address in the Ethernet header of an outgoing packet to make sure the reply will be sent to the host interface. When VirtualBox sees an incoming packet with a destination IP address that belongs to one of the virtual machine adapters it replaces the destination MAC address in the Ethernet header with the VM adapter’s MAC address and passes it on. VirtualBox examines ARP and DHCP packets in order to learn the IP addresses of virtual machines.
Depending on your host operating system, the following limitations should be kept in mind:
• On Macintosh hosts, functionality is limited when using AirPort (the Mac’s wireless networking) for bridged networking. Currently, VirtualBox supports only IPv4 over AirPort.
For other protocols such as IPv6 and IPX, you must choose a wired interface.
• On Linux hosts, functionality is limited when using wireless interfaces for bridged networking. Currently, VirtualBox supports only IPv4 over wireless. For other protocols such as IPv6 and IPX, you must choose a wired interface.
Also, setting the MTU to less than 1500 bytes on wired interfaces provided by the sky2 driver on the Marvell Yukon II EC Ultra Ethernet NIC is known to cause packet losses under certain conditions.
2 For

Mac OS X and Solaris hosts, net ﬁlter drivers were already added in VirtualBox 2.0 (as initial support for Host
Interface Networking on these platforms). With VirtualBox 2.1, net ﬁlter drivers were also added for the Windows and Linux hosts, replacing the mechanisms previously present in VirtualBox for those platforms; especially on Linux, the earlier method required creating TAP interfaces and bridges, which was complex and varied from one distribution to the next. None of this is necessary anymore. Bridged network was formerly called “Host Interface Networking” and has been renamed with version 2.2 without any change in functionality.

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Some adapters strip VLAN tags in hardware. This does not allow to use VLAN trunking between VM and the external network with pre-2.6.27 Linux kernels nor with host operating systems other than Linux.
• On Solaris hosts, there is no support for using wireless interfaces. Filtering guest trafﬁc using IPFilter is also not completely supported due to technical restrictions of the Solaris networking subsystem. These issues would be addressed in a future release of Solaris 11.
Starting with VirtualBox 4.1, on Solaris 11 hosts (build 159 and above), it is possible to use
Solaris’ Crossbow Virtual Network Interfaces (VNICs) directly with VirtualBox without any additional conﬁguration other than each VNIC must be exclusive for every guest network interface. Starting with VirtualBox 2.0.4 and up to VirtualBox 4.0, VNICs can be used but with the following caveats:
– A VNIC cannot be shared between multiple guest network interfaces, i.e. each guest network interface must have its own, exclusive VNIC.
– The VNIC and the guest network interface that uses the VNIC must be assigned identical MAC addresses.
When using VLAN interfaces with VirtualBox, they must be named according to the PPAhack naming scheme (e.g. “e1000g513001”), as otherwise the guest may receive packets in an unexpected format.

6.6 Internal networking
Internal Networking is similar to bridged networking in that the VM can directly communicate with the outside world. However, the “outside world” is limited to other VMs on the same host which connect to the same internal network.
Even though technically, everything that can be done using internal networking can also be done using bridged networking, there are security advantages with internal networking. In bridged networking mode, all trafﬁc goes through a physical interface of the host system. It is therefore possible to attach a packet sniffer (such as Wireshark) to the host interface and log all trafﬁc that goes over it. If, for any reason, you prefer two or more VMs on the same machine to communicate privately, hiding their data from both the host system and the user, bridged networking therefore is not an option.
Internal networks are created automatically as needed, i.e. there is no central conﬁguration.
Every internal network is identiﬁed simply by its name. Once there is more than one active virtual network card with the same internal network ID, the VirtualBox support driver will automatically
“wire” the cards and act as a network switch. The VirtualBox support driver implements a complete Ethernet switch and supports both broadcast/multicast frames and promiscuous mode.
In order to attach a VM’s network card to an internal network, set its networking mode to
“internal networking”. There are two ways to accomplish this:
• You can use a VM’s “Settings” dialog in the VirtualBox graphical user interface. In the
“Networking” category of the settings dialog, select “Internal Networking” from the dropdown list of networking modes. Now select the name of an existing internal network from the drop-down below or enter a new name into the entry ﬁeld.
• You can use
VBoxManage modifyvm "VM name" --nic<x> intnet

Optionally, you can specify a network name with the command
VBoxManage modifyvm "VM name" --intnet<x> "network name"

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6 Virtual networking
If you do not specify a network name, the network card will be attached to the network intnet by default.
Unless you conﬁgure the (virtual) network cards in the guest operating systems that are participating in the internal network to use static IP addresses, you may want to use the DHCP server that is built into VirtualBox to manage IP addresses for the internal network. Please see chapter
8.34, VBoxManage dhcpserver, page 162 for details.
As a security measure, the Linux implementation of internal networking only allows VMs running under the same user ID to establish an internal network.

6.7 Host-only networking
Host-only networking is another networking mode that was added with version 2.2 of VirtualBox.
It can be thought of as a hybrid between the bridged and internal networking modes: as with bridged networking, the virtual machines can talk to each other and the host as if they were connected through a physical Ethernet switch. Similarly, as with internal networking however, a physical networking interface need not be present, and the virtual machines cannot talk to the world outside the host since they are not connected to a physical networking interface.
Instead, when host-only networking is used, VirtualBox creates a new software interface on the host which then appears next to your existing network interfaces. In other words, whereas with bridged networking an existing physical interface is used to attach virtual machines to, with host-only networking a new “loopback” interface is created on the host. And whereas with internal networking, the trafﬁc between the virtual machines cannot be seen, the trafﬁc on the
“loopback” interface on the host can be intercepted.
Host-only networking is particularly useful for preconﬁgured virtual appliances, where multiple virtual machines are shipped together and designed to cooperate. For example, one virtual machine may contain a web server and a second one a database, and since they are intended to talk to each other, the appliance can instruct VirtualBox to set up a host-only network for the two. A second (bridged) network would then connect the web server to the outside world to serve data to, but the outside world cannot connect to the database.
To change a virtual machine’s virtual network interface to “host only” mode:
• either go to the “Network” page in the virtual machine’s settings notebook in the graphical user interface and select “Host-only networking”, or
• on the command line, type VBoxManage modifyvm "VM name" --nic<x> hostonly; see chapter 8.8, VBoxManage modifyvm, page 129 for details.
Before you can attach a VM to a host-only network you have to create at least one host-only interface, either from the GUI: “File” -> “Preferences” -> “Network” -> “Host-only network” ->
“(+)Add host-only network”, or via command line with
VBoxManage hostonlyif create

see chapter 8.33, VBoxManage hostonlyif, page 162 for details.
For host-only networking, like with internal networking, you may ﬁnd the DHCP server useful that is built into VirtualBox. This can be enabled to then manage the IP addresses in the host-only network since otherwise you would need to conﬁgure all IP addresses statically.
• In the VirtualBox graphical user interface, you can conﬁgure all these items in the global settings via “File” -> “Preferences” -> “Network”, which lists all host-only networks which are presently in use. Click on the network name and then on the “Edit” button to the right, and you can modify the adapter and DHCP settings.
• Alternatively, you can use VBoxManage dhcpserver on the command line; please see chapter 8.34, VBoxManage dhcpserver, page 162 for details.

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Note: On Linux and Mac OS X hosts the number of host-only interfaces is limited to
128. There is no such limit for Solaris and Windows hosts.

6.8 UDP Tunnel networking
This networking mode allows to interconnect virtual machines running on different hosts.
Technically this is done by encapsulating Ethernet frames sent or received by the guest network card into UDP/IP datagrams, and sending them over any network available to the host.
UDP Tunnel mode has three parameters:
Source UDP port The port on which the host listens. Datagrams arriving on this port from any source address will be forwarded to the receiving part of the guest network card.
Destination address IP address of the target host of the transmitted data.
Destination UDP port Port number to which the transmitted data is sent.
When interconnecting two virtual machines on two different hosts, their IP addresses must be swapped. On single host, source and destination UDP ports must be swapped.
In the following example host 1 uses the IP address 10.0.0.1 and host 2 uses IP address
10.0.0.2. Conﬁguration via command-line:
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage

modifyvm modifyvm modifyvm modifyvm modifyvm

"VM
"VM
"VM
"VM
"VM

01
01
01
01
01

on on on on on

host host host host host

1"
1"
1"
1"
1"

--nic<x> generic
--nicgenericdrv<x> UDPTunnel
--nicproperty<x> dest=10.0.0.2
--nicproperty<x> sport=10001
--nicproperty<x> dport=10002

VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage

modifyvm modifyvm modifyvm modifyvm modifyvm

"VM
"VM
"VM
"VM
"VM

02
02
02
02
02

on on on on on

host host host host host

2"
2"
2"
2"
2"

--nic<y> generic
--nicgenericdrv<y> UDPTunnel
--nicproperty<y> dest=10.0.0.1
--nicproperty<y> sport=10002
--nicproperty<y> dport=10001

and

Of course, you can always interconnect two virtual machines on the same host, by setting the destination address parameter to 127.0.0.1 on both. It will act similarly to “Internal network” in this case, however the host can see the network trafﬁc which it could not in the normal Internal network case.
Note: On Unix-based hosts (e.g. Linux, Solaris, Mac OS X) it is not possible to bind to ports below 1024 from applications that are not run by root. As a result, if you try to conﬁgure such a source UDP port, the VM will refuse to start.

6.9 VDE networking
Virtual Distributed Ethernet (VDE3 ) is a ﬂexible, virtual network infrastructure system, spanning across multiple hosts in a secure way. It allows for L2/L3 switching, including spanning-tree protocol, VLANs, and WAN emulation. It is an optional part of VirtualBox which is only included in the source code.
The basic building blocks of the infrastructure are VDE switches, VDE plugs and VDE wires which inter-connect the switches.
The VirtualBox VDE driver has one parameter:
3 VDE

is a project developed by Renzo Davoli, Associate Professor at the University of Bologna, Italy.

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6 Virtual networking
VDE network The name of the VDE network switch socket to which the VM will be connected.
The following basic example shows how to connect a virtual machine to a VDE switch:
1. Create a VDE switch: vde_switch -s /tmp/switch1

2. Conﬁguration via command-line:
VBoxManage modifyvm "VM name" --nic<x> generic
VBoxManage modifyvm "VM name" --nicgenericdrv<x> VDE

To connect to automatically allocated switch port, use:
VBoxManage modifyvm "VM name" --nicproperty<x> network=/tmp/switch1

To connect to speciﬁc switch port <n>, use:
VBoxManage modifyvm "VM name" --nicproperty<x> network=/tmp/switch1[<n>]

The latter option can be useful for VLANs.
3. Optionally map between VDE switch port and VLAN: (from switch CLI) vde$ vlan/create <VLAN> vde$ port/setvlan <port> <VLAN>

VDE is available on Linux and FreeBSD hosts only. It is only available if the VDE software and the VDE plugin library from the VirtualSquare project are installed on the host system4 . For more information on setting up VDE networks, please see the documentation accompanying the software.5 6.10 Limiting bandwidth for network I/O
Starting with version 4.2, VirtualBox allows for limiting the maximum bandwidth used for network transmission. Several network adapters of one VM may share limits through bandwidth groups. It is possible to have more than one such limit.
Note: VirtualBox shapes VM trafﬁc only in the transmit direction, delaying the packets being sent by virtual machines. It does not limit the trafﬁc being received by virtual machines. Limits are conﬁgured through VBoxManage. The example below creates a bandwidth group named “Limit”, sets the limit to 20 Mbit/s and assigns the group to the ﬁrst and second adapters of the VM:
VBoxManage bandwidthctl "VM name" add Limit --type network --limit 20m
VBoxManage modifyvm "VM name" --nicbandwidthgroup1 Limit
VBoxManage modifyvm "VM name" --nicbandwidthgroup2 Limit

All adapters in a group share the bandwidth limit, meaning that in the example above the bandwidth of both adapters combined can never exceed 20 Mbit/s. However, if one adapter doesn’t require bandwidth the other can use the remaining bandwidth of its group.
The limits for each group can be changed while the VM is running, with changes being picked up immediately. The example below changes the limit for the group created in the example above to 100 Kbit/s:
4 For

Linux hosts, the shared library libvdeplug.so must be available in the search path for shared libraries

5 http://wiki.virtualsquare.org/wiki/index.php/VDE_Basic_Networking.

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VBoxManage bandwidthctl "VM name" set Limit --limit 100k

To completely disable shaping for the ﬁrst adapter of VM use the following command:
VBoxManage modifyvm "VM name" --nicbandwidthgroup1 none

It is also possible to disable shaping for all adapters assigned to a bandwidth group while VM is running, by specifying the zero limit for the group. For example, for the bandwidth group named “Limit” use:
VBoxManage bandwidthctl "VM name" set Limit --limit 0

6.11 Improving network performance
VirtualBox provides a variety of virtual network adapters that can be “attached” to the host’s network in a number of ways. Depending on which types of adapters and attachments are used the network performance will be different. Performance-wise the virtio network adapter is preferable over Intel PRO/1000 emulated adapters, which are preferred over PCNet family of adapters. Both virtio and Intel PRO/1000 adapters enjoy the beneﬁt of segmentation and checksum ofﬂoading. Segmentation ofﬂoading is essential for high performance as it allows for less context switches, dramatically increasing the sizes of packets that cross VM/host boundary.
Note: Neither virtio nor Intel PRO/1000 drivers for Windows XP support segmentation ofﬂoading. Therefore Windows XP guests never reach the same transmission rates as other guest types. Refer to MS Knowledge base article 842264 for additional information.
Three attachment types: internal, bridged and host-only, have nearly identical performance, the internal type being a little bit faster and using less CPU cycles as the packets never reach the host’s network stack. The NAT attachment is the slowest (and safest) of all attachment types as it provides network address translation. The generic driver attachment is special and cannot be considered as an alternative to other attachment types.
The number of CPUs assigned to VM does not improve network performance and in some cases may hurt it due to increased concurrency in the guest.
Here is the short summary of things to check in order to improve network performance:
1. Whenever possible use virtio network adapter, otherwise use one of Intel PRO/1000 adapters; 2. Use bridged attachment instead of NAT;
3. Make sure segmentation ofﬂoading is enabled in the guest OS. Usually it will be enabled by default. You can check and modify ofﬂoading settings using ethtool command in Linux guests. 104

7 Remote virtual machines
7.1 Remote display (VRDP support)
VirtualBox can display virtual machines remotely, meaning that a virtual machine can execute on one computer even though the machine will be displayed on a second computer, and the machine will be controlled from there as well, as if the virtual machine was running on that second computer.
For maximum ﬂexibility, starting with VirtualBox 4.0, VirtualBox implements remote machine display through a generic extension interface, the VirtualBox Remote Desktop Extension (VRDE).
The base open-source VirtualBox package only provides this interface, while implementations can be supplied by third parties with VirtualBox extension packages, which must be installed separately from the base package. See chapter 1.5, Installing VirtualBox and extension packs, page 15 for more information.
Oracle provides support for the VirtualBox Remote Display Protocol (VRDP) in such a
VirtualBox extension package. When this package is installed, VirtualBox versions 4.0 and later support VRDP the same way as binary (non-open-source) versions of VirtualBox before 4.0 did.
VRDP is a backwards-compatible extension to Microsoft’s Remote Desktop Protocol (RDP). As a result, you can use any standard RDP client to control the remote VM.
Even when the extension is installed, the VRDP server is disabled by default. It can easily be enabled on a per-VM basis either in the VirtualBox Manager in the “Display” settings (see chapter
3.5, Display settings, page 50) or with VBoxManage:
VBoxManage modifyvm "VM name" --vrde on

By default, the VRDP server uses TCP port 3389. You will need to change the default port if you run more than one VRDP server, since the port can only be used by one server at a time; you might also need to change it on Windows hosts since the default port might already be used by the RDP server that is built into Windows itself. Ports 5000 through 5050 are typically not used and might be a good choice.
The port can be changed either in the “Display” settings of the graphical user interface or with --vrdeport option of the VBoxManage modifyvm command. You can specify a commaseparated list of ports or ranges of ports. Use a dash between two port numbers to specify a range. The VRDP server will bind to one of available ports from the speciﬁed list. For example,
VBoxManage modifyvm "VM name" --vrdeport 5000,5010-5012 will conﬁgure the server to bind to one of the ports 5000, 5010, 5011 or 5012. See chapter 8.8.5, Remote machine settings, page 136 for details.
The actual port used by a running VM can be either queried with VBoxManage showvminfo command or seen in the GUI on the “Runtime” tab of the “Session Information Dialog”, which is accessible via the “Machine” menu of the VM window.
Support for IPv6 has been implemented in VirtualBox 4.3. If the host OS supports IPv6 the
VRDP server will automatically listen for IPv6 connections in addition to IPv4.

7.1.1 Common third-party RDP viewers
Since VRDP is backwards-compatible to RDP, you can use any standard RDP viewer to connect to such a remote virtual machine (examples follow below). For this to work, you must specify the IP address of your host system (not of the virtual machine!) as the server address to connect to, as well as the port number that the VRDP server is using.

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Here follow examples for the most common RDP viewers:
• On Windows, you can use the Microsoft Terminal Services Connector (mstsc.exe) that ships with Windows. You can start it by bringing up the “Run” dialog (press the Windows key and “R”) and typing “mstsc”. You can also ﬁnd it under “Start” -> “All Programs” ->
“Accessories” -> “Remote Desktop Connection”. If you use the “Run” dialog, you can type in options directly: mstsc 1.2.3.4:3389

Replace 1.2.3.4 with the host IP address, and 3389 with a different port if necessary.
Note: IPv6 address must be enclosed in square brackets to specify a port. For example: mstsc [fe80::1:2:3:4]:3389

Note: When connecting to localhost in order to test the connection, the addresses localhost and 127.0.0.1 might not work using mstsc.exe. Instead, the address
127.0.0.2[:3389] has to be used.

• On other systems, you can use the standard open-source rdesktop program. This ships with most Linux distributions, but VirtualBox also comes with a modiﬁed variant of rdesktop for remote USB support (see chapter 7.1.4, Remote USB, page 109 below).
With rdesktop, use a command line such as the following: rdesktop -a 16 -N 1.2.3.4:3389

As said for the Microsoft viewer above, replace 1.2.3.4 with the host IP address, and
3389 with a different port if necessary. The -a 16 option requests a color depth of 16 bits per pixel, which we recommend. (For best performance, after installation of the guest operating system, you should set its display color depth to the same value). The -N option enables use of the NumPad keys.
• If you run the KDE desktop, you might prefer krdc, the KDE RDP viewer. The command line would look like this: krdc rdp://1.2.3.4:3389

Again, replace 1.2.3.4 with the host IP address, and 3389 with a different port if necessary.
The “rdp://“ bit is required with krdc to switch it into RDP mode.
• With Sun Ray thin clients you can use uttsc, which is part of the Sun Ray Windows
Connector package. See the corresponding documentation for details.

7.1.2 VBoxHeadless, the remote desktop server
While any VM started from the VirtualBox Manager is capable of running virtual machines remotely, it is not convenient to have to run the full-ﬂedged GUI if you never want to have VMs displayed locally in the ﬁrst place. In particular, if you are running server hardware whose only purpose is to host VMs, and all your VMs are supposed to run remotely over VRDP, then it is pointless to have a graphical user interface on the server at all – especially since, on a Linux or
Solaris host, the VirtualBox manager comes with dependencies on the Qt and SDL libraries. This is inconvenient if you would rather not have the X Window system on your server at all.

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VirtualBox therefore comes with yet another front-end called VBoxHeadless, which produces no visible output on the host at all, but still can deliver VRDP data. This front-end has no dependencies on the X Window system on Linux and Solaris hosts.1
To start a virtual machine with VBoxHeadless, you have three options:
• You can use
VBoxManage startvm "VM name" --type headless

The extra --type option causes VirtualBox to use VBoxHeadless as the front-end to the internal virtualization engine instead of the Qt front-end.
• One alternative is to use VBoxHeadless directly, as follows:
VBoxHeadless --startvm <uuid|name>

This way of starting the VM helps troubleshooting problems reported by VBoxManage startvm ... because you can see sometimes more detailed error messages, especially for early failures before the VM execution is started. In normal situations VBoxManage startvm is preferred since it runs the VM directly as a background process which has to be done explicitly when directly starting VBoxHeadless.
• The other alternative is to start VBoxHeadless from the VirtualBox Manager GUI, by holding the Shift key when starting a virtual machine or selecting Headless Start from the
Machine menu.
Since VirtualBox version 5.0, when you use VBoxHeadless to start a VM, the VRDP server will be enabled according to the VM conﬁguration. You can override the VM’s setting using --vrde command line parameter. To enable the VRDP server start the VM like this:
VBoxHeadless --startvm <uuid|name> --vrde on

and to disable it:
VBoxHeadless --startvm <uuid|name> --vrde off

To have the VRDP server enabled depending on the VM conﬁguration, as the other front-ends would, you can still use:
VBoxHeadless --startvm <uuid|name> --vrde config

but this is the same as
VBoxHeadless --startvm <uuid|name>

If you start the VM with VBoxManage startvm ... then the conﬁguration settings of the VM are always used.

7.1.3 Step by step: creating a virtual machine on a headless server
The following instructions may give you an idea how to create a virtual machine on a headless server over a network connection. We will create a virtual machine, establish an RDP connection and install a guest operating system – all without having to touch the headless server. All you need is the following:
1. VirtualBox on a server machine with a supported host operating system. The VirtualBox extension pack for the VRDP server must be installed (see the previous section). For the following example, we will assume a Linux server.
1 Before VirtualBox 1.6,

the headless server was called VBoxVRDP. For the sake of backwards compatibility, the VirtualBox installation still installs an executable with that name as well.

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2. An ISO ﬁle accessible from the server, containing the installation data for the guest operating system to install (we will assume Windows XP in the following example).
3. A terminal connection to that host through which you can access a command line (e.g. via ssh). 4. An RDP viewer on the remote client; see chapter 7.1.1, Common third-party RDP viewers, page 105 above for examples.
Note again that on the server machine, since we will only use the headless server, neither Qt nor
SDL nor the X Window system will be needed.
1. On the headless server, create a new virtual machine:
VBoxManage createvm --name "Windows XP" --ostype WindowsXP --register

Note that if you do not specify --register, you will have to manually use the registervm command later.
Note further that you do not need to specify --ostype, but doing so selects some sane default values for certain VM parameters, for example the RAM size and the type of the virtual network device. To get a complete list of supported operating systems you can use
VBoxManage list ostypes

2. Make sure the settings for this VM are appropriate for the guest operating system that we will install. For example:
VBoxManage modifyvm "Windows XP" --memory 256 --acpi on --boot1 dvd --nic1 nat

3. Create a virtual hard disk for the VM (in this case, 10 GB in size):
VBoxManage createhd --filename "WinXP.vdi" --size 10000

4. Add an IDE Controller to the new VM:
VBoxManage storagectl "Windows XP" --name "IDE Controller"
--add ide --controller PIIX4

5. Set the VDI ﬁle created above as the ﬁrst virtual hard disk of the new VM:
VBoxManage storageattach "Windows XP" --storagectl "IDE Controller"
--port 0 --device 0 --type hdd --medium "WinXP.vdi"

6. Attach the ISO ﬁle that contains the operating system installation that you want to install later to the virtual machine, so the machine can boot from it:
VBoxManage storageattach "Windows XP" --storagectl "IDE Controller"
--port 0 --device 1 --type dvddrive --medium /full/path/to/iso.iso

7. Enable VirtualBox remote desktop extension (the VRDP server):
VBoxManage modifyvm "Windows XP" --vrde on

8. Start the virtual machine using VBoxHeadless:
VBoxHeadless --startvm "Windows XP"

If everything worked, you should see a copyright notice. If, instead, you are returned to the command line, then something went wrong.
9. On the client machine, ﬁre up the RDP viewer and try to connect to the server (see chapter
7.1.1, Common third-party RDP viewers, page 105 above for how to use various common
RDP viewers).
You should now be seeing the installation routine of your guest operating system remotely in the RDP viewer.

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7.1.4 Remote USB
As a special feature on top of the VRDP support, VirtualBox supports remote USB devices over the wire as well. That is, the VirtualBox guest that runs on one computer can access the USB devices of the remote computer on which the VRDP data is being displayed the same way as
USB devices that are connected to the actual host. This allows for running virtual machines on a VirtualBox host that acts as a server, where a client can connect from elsewhere that needs only a network adapter and a display capable of running an RDP viewer. When USB devices are plugged into the client, the remote VirtualBox server can access them.
For these remote USB devices, the same ﬁlter rules apply as for other USB devices, as described with chapter 3.10.1, USB settings, page 55. All you have to do is specify “Remote” (or “Any”) when setting up these rules.
Accessing remote USB devices is only possible if the RDP client supports this extension.
On Linux and Solaris hosts, the VirtualBox installation provides a suitable VRDP client called rdesktop-vrdp. Recent versions of uttsc, a client tailored for the use with Sun Ray thin clients, also support accessing remote USB devices. RDP clients for other platforms will be provided in future VirtualBox versions.
To make a remote USB device available to a VM, rdesktop-vrdp should be started as follows: rdesktop-vrdp -r usb -a 16 -N my.host.address

Please refer to chapter 12.8.7, USB not working, page 241 for further details on how to properly set up the permissions for USB devices. Furthermore it is advisable to disable automatic loading of any host driver on the remote host which might work on USB devices to ensure that the devices are accessible by the RDP client. If the setup was properly done on the remote host, plug/unplug events are visible on the VBox.log ﬁle of the VM.

7.1.5 RDP authentication
For each virtual machine that is remotely accessible via RDP, you can individually determine if and how client connections are authenticated. For this, use VBoxManage modifyvm command with the --vrdeauthtype option; see chapter 8.8, VBoxManage modifyvm, page 129 for a general introduction. Three methods of authentication are available:
• The “null” method means that there is no authentication at all; any client can connect to the VRDP server and thus the virtual machine. This is, of course, very insecure and only to be recommended for private networks.
• The “external” method provides external authentication through a special authentication library. VirtualBox ships with two such authentication libraries:
1. The default authentication library, VBoxAuth, authenticates against user credentials of the hosts. Depending on the host platform, this means:
– On Linux hosts, VBoxAuth.so authenticates users against the host’s PAM system.
– On Windows hosts, VBoxAuth.dll authenticates users against the host’s WinLogon system.
– On Mac OS X hosts, VBoxAuth.dylib authenticates users against the host’s directory service.2
In other words, the “external” method per default performs authentication with the user accounts that exist on the host system. Any user with valid authentication credentials is accepted, i.e. the username does not have to correspond to the user running the VM.
2 Support

for Mac OS X was added in version 3.2.

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2. An additional library called VBoxAuthSimple performs authentication against credentials conﬁgured in the “extradata” section of a virtual machine’s XML settings ﬁle. This is probably the simplest way to get authentication that does not depend on a running and supported guest (see below). The following steps are required:
a) Enable VBoxAuthSimple with the following command:
VBoxManage setproperty vrdeauthlibrary "VBoxAuthSimple"

b) To enable the library for a particular VM, you must then switch authentication to external: VBoxManage modifyvm "VM name" --vrdeauthtype external

Replace <vm> with the VM name or UUID.
c) You will then need to conﬁgure users and passwords by writing items into the machine’s extradata. Since the XML machine settings ﬁle, into whose “extradata” section the password needs to be written, is a plain text ﬁle, VirtualBox uses hashes to encrypt passwords. The following command must be used:
VBoxManage setextradata "VM name" "VBoxAuthSimple/users/<user>" <hash>

Replace <vm> with the VM name or UUID, <user> with the user name who should be allowed to log in and <hash> with the encrypted password. As an example, to obtain the hash value for the password “secret”, you can use the following command: VBoxManage internalcommands passwordhash "secret"

This will print
2bb80d537b1da3e38bd30361aa855686bde0eacd7162fef6a25fe97bf527a25b

You can then use VBoxManage setextradata to store this value in the machine’s
“extradata” section.
As example, combined together, to set the password for the user “john” and the machine “My VM” to “secret”, use this command:
VBoxManage setextradata "My VM" "VBoxAuthSimple/users/john"
2bb80d537b1da3e38bd30361aa855686bde0eacd7162fef6a25fe97bf527a25b

• Finally, the “guest” authentication method performs authentication with a special component that comes with the Guest Additions; as a result, authentication is not performed on the host, but with the guest user accounts.
This method is currently still in testing and not yet supported.
In addition to the methods described above, you can replace the default “external” authentication module with any other module. For this, VirtualBox provides a well-deﬁned interface that allows you to write your own authentication module. This is described in detail in the VirtualBox
Software Development Kit (SDK) reference; please see chapter 11, VirtualBox programming interfaces, page 225 for details.

7.1.6 RDP encryption
RDP features data stream encryption, which is based on the RC4 symmetric cipher (with keys up to 128bit). The RC4 keys are being replaced in regular intervals (every 4096 packets).
RDP provides different authentication methods:
1. Historically, RDP4 authentication was used, with which the RDP client does not perform any checks in order to verify the identity of the server it connects to. Since user credentials can be obtained using a “man in the middle” (MITM) attack, RDP4 authentication is insecure and should generally not be used.

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2. RDP5.1 authentication employs a server certiﬁcate for which the client possesses the public key. This way it is guaranteed that the server possess the corresponding private key. However, as this hard-coded private key became public some years ago, RDP5.1 authentication is also insecure.
3. RDP5.2 authentication uses the Enhanced RDP Security, which means that an external security protocol is used to secure the connection. RDP4 and RDP5.1 use Standard RDP
Security. The VRDP server supports Enhanced RDP Security with TLS protocol and, as a part of TLS handshake, sends the server certiﬁcate to the client.
The Security/Method VRDE property sets the desired security method, which is used for a connection. Valid values are:
• Negotiate - both Enhanced (TLS) and Standard RDP Security connections are allowed. The security method is negotiated with the client. This is the default setting.
• RDP - only Standard RDP Security is accepted.
• TLS - only Enhanced RDP Security is accepted. The client must support TLS.
For example the following command allows a client to use either Standard or Enhanced
RDP Security connection: vboxmanage modifyvm "VM name" --vrdeproperty "Security/Method=negotiate"

If the Security/Method property is set to either Negotiate or TLS, the TLS protocol will be automatically used by the server, if the client supports TLS. However, in order to use TLS the server must possess the Server Certiﬁcate, the Server Private Key and the
Certiﬁcate Authority (CA) Certiﬁcate. The following example shows how to generate a server certiﬁcate.
a) Create a CA self signed certiﬁcate: openssl req -new -x509 -days 365 -extensions v3_ca \
-keyout ca_key_private.pem -out ca_cert.pem

b) Generate a server private key and a request for signing: openssl genrsa -out server_key_private.pem openssl req -new -key server_key_private.pem -out server_req.pem

c) Generate the server certiﬁcate: openssl x509 -req -days 365 -in server_req.pem \
-CA ca_cert.pem -CAkey ca_key_private.pem -set_serial 01 -out server_cert.pem

The server must be conﬁgured to access the required ﬁles: vboxmanage modifyvm "VM name" \
--vrdeproperty "Security/CACertificate=path/ca_cert.pem" vboxmanage modifyvm "VM name" \
--vrdeproperty "Security/ServerCertificate=path/server_cert.pem" vboxmanage modifyvm "VM name" \
--vrdeproperty "Security/ServerPrivateKey=path/server_key_private.pem"

As the client that connects to the server determines what type of encryption will be used, with rdesktop, the Linux RDP viewer, use the -4 or -5 options.

7.1.7 Multiple connections to the VRDP server
The VRDP server of VirtualBox supports multiple simultaneous connections to the same running
VM from different clients. All connected clients see the same screen output and share a mouse pointer and keyboard focus. This is similar to several people using the same computer at the same time, taking turns at the keyboard.
The following command enables multiple connection mode:
VBoxManage modifyvm "VM name" --vrdemulticon on

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7.1.8 Multiple remote monitors
To access two or more remote VM displays you have to enable the VRDP multiconnection mode
(see chapter 7.1.7, Multiple connections to the VRDP server, page 111).
The RDP client can select the virtual monitor number to connect to using the domain logon parameter (-d). If the parameter ends with @ followed by a number, VirtualBox interprets this number as the screen index. The primary guest screen is selected with @1, the ﬁrst secondary screen is @2, etc.
The Microsoft RDP6 client does not let you specify a separate domain name. Instead, use domain\username in the Username: ﬁeld – for example, @2\name. name must be supplied, and must be the name used to log in if the VRDP server is set up to require credentials. If it is not, you may use any text as the username.

7.1.9 VRDP video redirection
Starting with VirtualBox 3.2, the VRDP server can redirect video streams from the guest to the
RDP client. Video frames are compressed using the JPEG algorithm allowing a higher compression ratio than standard RDP bitmap compression methods. It is possible to increase the compression ratio by lowering the video quality.
The VRDP server automatically detects video streams in a guest as frequently updated rectangular areas. As a result, this method works with any guest operating system without having to install additional software in the guest; in particular, the Guest Additions are not required.
On the client side, however, currently only the Windows 7 Remote Desktop Connection client supports this feature. If a client does not support video redirection, the VRDP server falls back to regular bitmap updates.
The following command enables video redirection:
VBoxManage modifyvm "VM name" --vrdevideochannel on

The quality of the video is deﬁned as a value from 10 to 100 percent, representing a JPEG compression level (where lower numbers mean lower quality but higher compression). The quality can be changed using the following command:
VBoxManage modifyvm "VM name" --vrdevideochannelquality 75

7.1.10 VRDP customization
With VirtualBox 4.0 it is possible to disable display output, mouse and keyboard input, audio, remote USB or clipboard individually in the VRDP server.
The following commands change corresponding server settings:
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage

modifyvm modifyvm modifyvm modifyvm modifyvm modifyvm "VM
"VM
"VM
"VM
"VM
"VM

name" name" name" name" name" name" --vrdeproperty
--vrdeproperty
--vrdeproperty
--vrdeproperty
--vrdeproperty
--vrdeproperty

Client/DisableDisplay=1
Client/DisableInput=1
Client/DisableUSB=1
Client/DisableAudio=1
Client/DisableClipboard=1
Client/DisableUpstreamAudio=1

To reenable a feature use a similar command without the trailing 1. For example:
VBoxManage modifyvm "VM name" --vrdeproperty Client/DisableDisplay=

These properties were introduced with VirtualBox 3.2.10. However, in the 3.2.x series, it was necessary to use the following commands to alter these settings instead:
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage

setextradata setextradata setextradata setextradata setextradata

"VM
"VM
"VM
"VM
"VM

name" name" name" name" name"

"VRDP/Feature/Client/DisableDisplay" 1
"VRDP/Feature/Client/DisableInput" 1
"VRDP/Feature/Client/DisableUSB" 1
"VRDP/Feature/Client/DisableAudio" 1
"VRDP/Feature/Client/DisableClipboard" 1

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To reenable a feature use a similar command without the trailing 1. For example:
VBoxManage setextradata "VM name" "VRDP/Feature/Client/DisableDisplay"

7.2 Teleporting
Starting with version 3.1, VirtualBox supports “teleporting” – that is, moving a virtual machine over a network from one VirtualBox host to another, while the virtual machine is running. This works regardless of the host operating system that is running on the hosts: you can teleport virtual machines between Solaris and Mac hosts, for example.
Teleporting requires that a machine be currently running on one host, which is then called the “source”. The host to which the virtual machine will be teleported will then be called the
“target”; the machine on the target is then conﬁgured to wait for the source to contact the target.
The machine’s running state will then be transferred from the source to the target with minimal downtime. Teleporting happens over any TCP/IP network; the source and the target only need to agree on a TCP/IP port which is speciﬁed in the teleporting settings.
At this time, there are a few prerequisites for this to work, however:
1. On the target host, you must conﬁgure a virtual machine in VirtualBox with exactly the same hardware settings as the machine on the source that you want to teleport. This does not apply to settings which are merely descriptive, such as the VM name, but obviously for teleporting to work, the target machine must have the same amount of memory and other hardware settings. Otherwise teleporting will fail with an error message.
2. The two virtual machines on the source and the target must share the same storage (hard disks as well as ﬂoppy and CD/DVD images). This means that they either use the same iSCSI targets or that the storage resides somewhere on the network and both hosts have access to it via NFS or SMB/CIFS.
This also means that neither the source nor the target machine can have any snapshots.
Then perform the following steps:
1. On the target host, conﬁgure the virtual machine to wait for a teleport request to arrive when it is started, instead of actually attempting to start the machine. This is done with the following VBoxManage command:
VBoxManage modifyvm <targetvmname> --teleporter on --teleporterport <port>

where <targetvmname> is the name of the virtual machine on the target host and <port> is a TCP/IP port number to be used on both the source and the target hosts. For example, use 6000. For details, see chapter 8.8.6, Teleporting settings, page 137.
2. Start the VM on the target host. You will see that instead of actually running, it will show a progress dialog. indicating that it is waiting for a teleport request to arrive.
3. Start the machine on the source host as usual. When it is running and you want it to be teleported, issue the following command on the source host:
VBoxManage controlvm <sourcevmname> teleport --host <targethost> --port <port>

where <sourcevmname> is the name of the virtual machine on the source host (the machine that is currently running), <targethost> is the host or IP name of the target host on which the machine is waiting for the teleport request, and <port> must be the same number as speciﬁed in the command on the target host. For details, see chapter 8.13, VBoxManage controlvm, page 140.

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For testing, you can also teleport machines on the same host; in that case, use “localhost” as the hostname on both the source and the target host.
Note: In rare cases, if the CPUs of the source and the target are very different, teleporting can fail with an error message, or the target may hang. This may happen especially if the VM is running application software that is highly optimized to run on a particular CPU without correctly checking that certain CPU features are actually present. VirtualBox ﬁlters what CPU capabilities are presented to the guest operating system. Advanced users can attempt to restrict these virtual CPU capabilities with the
VBoxManage --modifyvm --cpuid command; see chapter 8.8.6, Teleporting settings, page 137.

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8.1 Introduction
As brieﬂy mentioned in chapter 1.16, Alternative front-ends, page 31, VBoxManage is the command-line interface to VirtualBox. With it, you can completely control VirtualBox from the command line of your host operating system. VBoxManage supports all the features that the graphical user interface gives you access to, but it supports a lot more than that. It exposes really all the features of the virtualization engine, even those that cannot (yet) be accessed from the
GUI.
You will need to use the command line if you want to
• use a different user interface than the main GUI (for example, VBoxSDL or the VBoxHeadless server);
• control some of the more advanced and experimental conﬁguration settings for a VM.
There are two main things to keep in mind when using VBoxManage: First, VBoxManage must always be used with a speciﬁc “subcommand”, such as “list” or “createvm” or “startvm”. All the subcommands that VBoxManage supports are described in detail in chapter 8, VBoxManage, page
115.
Second, most of these subcommands require that you specify a particular virtual machine after the subcommand. There are two ways you can do this:
• You can specify the VM name, as it is shown in the VirtualBox GUI. Note that if that name contains spaces, then you must enclose the entire name in double quotes (as it is always required with command line arguments that contain spaces).
For example:
VBoxManage startvm "Windows XP"

• You can specify the UUID, which is the internal unique identiﬁer that VirtualBox uses to refer to the virtual machine. Assuming that the aforementioned VM called “Windows XP” has the UUID shown below, the following command has the same effect as the previous:
VBoxManage startvm 670e746d-abea-4ba6-ad02-2a3b043810a5

You can type VBoxManage list vms to have all currently registered VMs listed with all their settings, including their respective names and UUIDs.
Some typical examples of how to control VirtualBox from the command line are listed below:
• To create a new virtual machine from the command line and immediately register it with
VirtualBox, use VBoxManage createvm with the --register option,1 like this:
$ VBoxManage createvm --name "SUSE 10.2" --register
VirtualBox Command Line Management Interface Version 5.0.0
(C) 2005-2015 Oracle Corporation
All rights reserved.
Virtual machine ’SUSE 10.2’ is created.
UUID: c89fc351-8ec6-4f02-a048-57f4d25288e5
Settings file: ’/home/username/.config/VirtualBox/Machines/SUSE 10.2/SUSE 10.2.xml’
1 For

details, see chapter 8.7, VBoxManage createvm, page 129.

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As can be seen from the above output, a new virtual machine has been created with a new
UUID and a new XML settings ﬁle.
• To show the conﬁguration of a particular VM, use VBoxManage showvminfo; see chapter
8.5, VBoxManage showvminfo, page 127 for details and an example.
• To change settings while a VM is powered off, use VBoxManage modifyvm, e.g. as follows:
VBoxManage modifyvm "Windows XP" --memory 512

For details, see chapter 8.8, VBoxManage modifyvm, page 129.
• To change the storage conﬁguration (e.g. to add a storage controller and then a virtual disk), use VBoxManage storagectl and VBoxManage storageattach; see chapter 8.19,
VBoxManage storagectl, page 146 and chapter 8.18, VBoxManage storageattach, page 144 for details.
• To control VM operation, use one of the following:
– To start a VM that is currently powered off, use VBoxManage startvm; see chapter
8.12, VBoxManage startvm, page 140 for details.
– To pause or save a VM that is currently running or change some of its settings, use
VBoxManage controlvm; see chapter 8.13, VBoxManage controlvm, page 140 for details.

8.2 Commands overview
When running VBoxManage without parameters or when supplying an invalid command line, the below syntax diagram will be shown. Note that the output will be slightly different depending on the host platform; when in doubt, check the output of VBoxManage for the commands available on your particular host.
Usage:
VBoxManage [<general option>] <command>

General Options:
[-v|--version]
[-q|--nologo]
[--settingspw <pw>]
[--settingspwfile <file>]

print version number and exit suppress the logo provide the settings password provide a file containing the settings password

Commands: list [--long|-l]

vms|runningvms|ostypes|hostdvds|hostfloppies| intnets|bridgedifs|hostonlyifs|natnets|dhcpservers| hostinfo|hostcpuids|hddbackends|hdds|dvds|floppies| usbhost|usbfilters|systemproperties|extpacks| groups|webcams|screenshotformats

showvminfo showvminfo <uuid|vmname> [--details]
[--machinereadable]
<uuid|vmname> --log <idx>

registervm

<filename>

unregistervm

<uuid|vmname> [--delete]

createvm

--name <name>

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8 VBoxManage
[--groups <group>, ...]
[--ostype <ostype>]
[--register]
[--basefolder <path>]
[--uuid <uuid>] modifyvm <uuid|vmname>
[--name <name>]
[--groups <group>, ...]
[--description <desc>]
[--ostype <ostype>]
[--iconfile <filename>]
[--memory <memorysize in MB>]
[--pagefusion on|off]
[--vram <vramsize in MB>]
[--acpi on|off]
[--pciattach 03:04.0]
[--pciattach 03:04.0@02:01.0]
[--pcidetach 03:04.0]
[--ioapic on|off]
[--hpet on|off]
[--triplefaultreset on|off]
[--paravirtprovider none|default|legacy|minimal| hyperv|kvm] [--hwvirtex on|off]
[--nestedpaging on|off]
[--largepages on|off]
[--vtxvpid on|off]
[--vtxux on|off]
[--pae on|off]
[--longmode on|off]
[--cpuid-portability-level <0..3>
[--cpuidset <leaf> <eax> <ebx> <ecx> <edx>]
[--cpuidremove <leaf>]
[--cpuidremoveall]
[--hardwareuuid <uuid>]
[--cpus <number>]
[--cpuhotplug on|off]
[--plugcpu <id>]
[--unplugcpu <id>]
[--cpuexecutioncap <1-100>]
[--rtcuseutc on|off]
[--graphicscontroller none|vboxvga|vmsvga]
[--monitorcount <number>]
[--accelerate3d on|off]
[--accelerate2dvideo on|off]
[--firmware bios|efi|efi32|efi64]
[--chipset ich9|piix3]
[--bioslogofadein on|off]
[--bioslogofadeout on|off]
[--bioslogodisplaytime <msec>]
[--bioslogoimagepath <imagepath>]
[--biosbootmenu disabled|menuonly|messageandmenu]
[--biossystemtimeoffset <msec>]
[--biospxedebug on|off]
[--boot<1-4> none|floppy|dvd|disk|net>]
[--nic<1-N> none|null|nat|bridged|intnet|hostonly| generic|natnetwork] [--nictype<1-N> Am79C970A|Am79C973|
82540EM|82543GC|82545EM|
virtio]
[--cableconnected<1-N> on|off]
[--nictrace<1-N> on|off]
[--nictracefile<1-N> <filename>]
[--nicproperty<1-N> name=[value]]
[--nicspeed<1-N> <kbps>]
[--nicbootprio<1-N> <priority>]

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[--nicpromisc<1-N> deny|allow-vms|allow-all]
[--nicbandwidthgroup<1-N> none|<name>]
[--bridgeadapter<1-N> none|<devicename>]
[--hostonlyadapter<1-N> none|<devicename>]
[--intnet<1-N> <network name>]
[--nat-network<1-N> <network name>]
[--nicgenericdrv<1-N> <driver>
[--natnet<1-N> <network>|default]
[--natsettings<1-N> [<mtu>],[<socksnd>],
[<sockrcv>],[<tcpsnd>],
[<tcprcv>]]
[--natpf<1-N> [<rulename>],tcp|udp,[<hostip>],
<hostport>,[<guestip>],<guestport>]
[--natpf<1-N> delete <rulename>]
[--nattftpprefix<1-N> <prefix>]
[--nattftpfile<1-N> <file>]
[--nattftpserver<1-N> <ip>]
[--natbindip<1-N> <ip>
[--natdnspassdomain<1-N> on|off]
[--natdnsproxy<1-N> on|off]
[--natdnshostresolver<1-N> on|off]
[--nataliasmode<1-N> default|[log],[proxyonly],
[sameports]]
[--macaddress<1-N> auto|<mac>]
[--mouse ps2|usb|usbtablet|usbmultitouch]
[--keyboard ps2|usb
[--uart<1-N> off|<I/O base> <IRQ>]
[--uartmode<1-N> disconnected| server <pipe>| client <pipe>| tcpserver <port>| tcpclient <hostname:port>| file <file>|
<devicename>]
[--lpt<1-N> off|<I/O base> <IRQ>]
[--lptmode<1-N> <devicename>]
[--guestmemoryballoon <balloonsize in MB>]
[--audio none|null|dsound|solaudio|oss|alsa|pulse| oss|pulse|coreaudio] [--audiocontroller ac97|hda|sb16]
[--audiocodec stac9700|ad1980|stac9221|sb16]
[--clipboard disabled|hosttoguest|guesttohost| bidirectional] [--draganddrop disabled|hosttoguest]
[--vrde on|off]
[--vrdeextpack default|<name>
[--vrdeproperty <name=[value]>]
[--vrdeport <hostport>]
[--vrdeaddress <hostip>]
[--vrdeauthtype null|external|guest]
[--vrdeauthlibrary default|<name>
[--vrdemulticon on|off]
[--vrdereusecon on|off]
[--vrdevideochannel on|off]
[--vrdevideochannelquality <percent>]
[--usb on|off]
[--usbehci on|off]
[--usbxhci on|off]
[--usbrename <oldname> <newname>]
[--snapshotfolder default|<path>]
[--teleporter on|off]
[--teleporterport <port>]
[--teleporteraddress <address|empty>
[--teleporterpassword <password>]
[--teleporterpasswordfile <file>|stdin]
[--tracing-enabled on|off]
[--tracing-config <config-string>]

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[--tracing-allow-vm-access on|off]
[--usbcardreader on|off]
[--autostart-enabled on|off]
[--autostart-delay <seconds>]
[--videocap on|off]
[--videocapscreens all|<screen ID> [<screen ID> ...]]
[--videocapfile <filename>]
[--videocapres <width> <height>]
[--videocaprate <rate>]
[--videocapfps <fps>]
[--videocapmaxtime <ms>]
[--videocapmaxsize <MB>]
[--videocapopts <key=value> [<key=value> ...]]
[--defaultfrontend default|<name>] clonevm <uuid|vmname>
[--snapshot <uuid>|<name>]
[--mode machine|machineandchildren|all]
[--options link|keepallmacs|keepnatmacs| keepdisknames] [--name <name>]
[--groups <group>, ...]
[--basefolder <basefolder>]
[--uuid <uuid>]
[--register]

import

<ovfname/ovaname>
[--dry-run|-n]
[--options keepallmacs|keepnatmacs|importtovdi]
[more options]
(run with -n to have options displayed for a particular OVF)

export

<machines> --output|-o <name>.<ovf/ova>
[--legacy09|--ovf09|--ovf10|--ovf20]
[--manifest]
[--iso]
[--options manifest|iso|nomacs|nomacsbutnat]
[--vsys <number of virtual system>]
[--product <product name>]
[--producturl <product url>]
[--vendor <vendor name>]
[--vendorurl <vendor url>]
[--version <version info>]
[--description <description info>]
[--eula <license text>]
[--eulafile <filename>]

startvm

<uuid|vmname>...
[--type gui|sdl|headless|separate]

controlvm

<uuid|vmname> pause|resume|reset|poweroff|savestate| acpipowerbutton|acpisleepbutton| keyboardputscancode <hex> [<hex> ...]| setlinkstate<1-N> on|off | nic<1-N> null|nat|bridged|intnet|hostonly|generic| natnetwork [<devicename>] | nictrace<1-N> on|off | nictracefile<1-N> <filename> | nicproperty<1-N> name=[value] | nicpromisc<1-N> deny|allow-vms|allow-all | natpf<1-N> [<rulename>],tcp|udp,[<hostip>],
<hostport>,[<guestip>],<guestport> | natpf<1-N> delete <rulename> | guestmemoryballoon <balloonsize in MB> | usbattach <uuid>|<address>

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[--capturefile <filename>] | usbdetach <uuid>|<address> | clipboard disabled|hosttoguest|guesttohost| bidirectional | draganddrop disabled|hosttoguest | vrde on|off | vrdeport <port> | vrdeproperty <name=[value]> | vrdevideochannelquality <percent> | setvideomodehint <xres> <yres> <bpp>
[[<display>] [<enabled:yes|no> |
[<xorigin> <yorigin>]]] | screenshotpng <file> [display] | videocap on|off | videocapscreens all|none|<screen>,[<screen>...] | videocapfile <file> videocapres <width>x<height> videocaprate <rate> videocapfps <fps> videocapmaxtime <ms> videocapmaxsize <MB> setcredentials <username>
--passwordfile <file> | <password>
<domain>
[--allowlocallogon <yes|no>] | teleport --host <name> --port <port>
[--maxdowntime <msec>]
[--passwordfile <file> |
--password <password>] | plugcpu <id> | unplugcpu <id> | cpuexecutioncap <1-100> webcam <attach [path [settings]]> | <detach [path]> | <list> addencpassword <id>
<password file>|[--removeonsuspend <yes|no>] removeencpassword <id> removeallencpasswords discardstate

<uuid|vmname>

adoptstate

<uuid|vmname> <state_file>

snapshot

<uuid|vmname> take <name> [--description <desc>] [--live]
[--uniquename Number,Timestamp,Space,Force] | delete <uuid|snapname> | restore <uuid|snapname> | restorecurrent | edit <uuid|snapname>|--current
[--name <name>]
[--description <desc>] | list [--details|--machinereadable] showvminfo <uuid|snapname>

closemedium

[disk|dvd|floppy] <uuid|filename>
[--delete]

storageattach

<uuid|vmname>
--storagectl <name>
[--port <number>]
[--device <number>]
[--type dvddrive|hdd|fdd]
[--medium none|emptydrive|additions|
<uuid|filename>|host:<drive>|iscsi]
[--mtype normal|writethrough|immutable|shareable| readonly|multiattach] 120

8 VBoxManage
[--comment <text>]
[--setuuid <uuid>]
[--setparentuuid <uuid>]
[--passthrough on|off]
[--tempeject on|off]
[--nonrotational on|off]
[--discard on|off]
[--hotpluggable on|off]
[--bandwidthgroup <name>]
[--forceunmount]
[--server <name>|<ip>]
[--target <target>]
[--tport <port>]
[--lun <lun>]
[--encodedlun <lun>]
[--username <username>]
[--password <password>]
[--initiator <initiator>]
[--intnet]
storagectl

<uuid|vmname>
--name <name>
[--add ide|sata|scsi|floppy|sas]
[--controller LSILogic|LSILogicSAS|BusLogic|
IntelAHCI|PIIX3|PIIX4|ICH6|I82078]
[--portcount <1-n>]
[--hostiocache on|off]
[--bootable on|off]
[--rename <name>]
[--remove]

bandwidthctl

<uuid|vmname> add <name> --type disk|network
--limit <megabytes per second>[k|m|g|K|M|G] | set <name>
--limit <megabytes per second>[k|m|g|K|M|G] | remove <name> | list [--machinereadable]
(limit units: k=kilobit, m=megabit, g=gigabit,
K=kilobyte, M=megabyte, G=gigabyte)

showmediuminfo

[disk|dvd|floppy] <uuid|filename>

createmedium

[disk|dvd|floppy] --filename <filename>
[--size <megabytes>|--sizebyte <bytes>]
[--diffparent <uuid>|<filename>
[--format VDI|VMDK|VHD] (default: VDI)
[--variant Standard,Fixed,Split2G,Stream,ESX]

modifymedium

[disk|dvd|floppy] <uuid|filename>
[--type normal|writethrough|immutable|shareable| readonly|multiattach] [--autoreset on|off]
[--property <name=[value]>]
[--compact]
[--resize <megabytes>|--resizebyte <bytes>]

clonemedium

[disk|dvd|floppy] <uuid|inputfile> <uuid|outputfile>
[--format VDI|VMDK|VHD|RAW|<other>]
[--variant Standard,Fixed,Split2G,Stream,ESX]
[--existing]

mediumproperty

[disk|dvd|floppy] set <uuid|filename>
<property> <value>
[disk|dvd|floppy] get <uuid|filename>
<property>

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[disk|dvd|floppy] delete <uuid|filename>
<property>
encryptmedium

<uuid|filename>
[--newpassword <file>|-]
[--oldpassword <file>|-]
[--cipher <cipher identifier>]
[--newpasswordid <password identifier>]

checkmediumpwd

<uuid|filename>
<pwd file>|-

convertfromraw

<filename> <outputfile>
[--format VDI|VMDK|VHD]
[--variant Standard,Fixed,Split2G,Stream,ESX]
[--uuid <uuid>] stdin <outputfile> <bytes>
[--format VDI|VMDK|VHD]
[--variant Standard,Fixed,Split2G,Stream,ESX]
[--uuid <uuid>]

convertfromraw

getextradata

global|<uuid|vmname>
<key>|enumerate

setextradata

global|<uuid|vmname>
<key>
[<value>] (no value deletes key)

setproperty

machinefolder default|<folder> | hwvirtexclusive on|off | vrdeauthlibrary default|<library> | websrvauthlibrary default|null|<library> | vrdeextpack null|<library> | autostartdbpath null|<folder> | loghistorycount <value> defaultfrontend default|<name> logginglevel <log setting>

usbfilter

add <index,0-N>
--target <uuid|vmname>|global
--name <string>
--action ignore|hold (global filters only)
[--active yes|no] (yes)
[--vendorid <XXXX>] (null)
[--productid <XXXX>] (null)
[--revision <IIFF>] (null)
[--manufacturer <string>] (null)
[--product <string>] (null)
[--remote yes|no] (null, VM filters only)
[--serialnumber <string>] (null)
[--maskedinterfaces <XXXXXXXX>]

usbfilter

modify <index,0-N>
--target <uuid|vmname>|global
[--name <string>]
[--action ignore|hold] (global filters only)
[--active yes|no]
[--vendorid <XXXX>|""]
[--productid <XXXX>|""]
[--revision <IIFF>|""]
[--manufacturer <string>|""]
[--product <string>|""]
[--remote yes|no] (null, VM filters only)
[--serialnumber <string>|""]
[--maskedinterfaces <XXXXXXXX>]

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8 VBoxManage usbfilter remove <index,0-N>
--target <uuid|vmname>|global

sharedfolder

add <uuid|vmname>
--name <name> --hostpath <hostpath>
[--transient] [--readonly] [--automount]

sharedfolder

remove <uuid|vmname>
--name <name> [--transient]

guestproperty

get <uuid|vmname>
<property> [--verbose]

guestproperty

set <uuid|vmname>
<property> [<value> [--flags <flags>]]

guestproperty

delete|unset <uuid|vmname>
<property>

guestproperty

enumerate <uuid|vmname>
[--patterns <patterns>]

guestproperty

wait <uuid|vmname> <patterns>
[--timeout <msec>] [--fail-on-timeout]

guestcontrol

<uuid|vmname> [--verbose|-v] [--quiet|-q]
[--username <name>] [--domain <domain>]
[--passwordfile <file> | --password <password>] run [common-options]
[--exe <path to executable>] [--timeout <msec>]
[-E|--putenv <NAME>[=<VALUE>]] [--unquoted-args]
[--ignore-operhaned-processes] [--no-profile]
[--no-wait-stdout|--wait-stdout]
[--no-wait-stderr|--wait-stderr]
[--dos2unix] [--unix2dos]
-- <program/arg0> [argument1] ... [argumentN]] start [common-options]
[--exe <path to executable>] [--timeout <msec>]
[-E|--putenv <NAME>[=<VALUE>]] [--unquoted-args]
[--ignore-operhaned-processes] [--no-profile]
-- <program/arg0> [argument1] ... [argumentN]] copyfrom [common-options]
[--dryrun] [--follow] [-R|--recursive]
<guest-src0> [guest-src1 [...]] <host-dst> copyfrom [common-options]
[--dryrun] [--follow] [-R|--recursive]
[--target-directory <host-dst-dir>]
<guest-src0> [guest-src1 [...]] copyto [common-options]
[--dryrun] [--follow] [-R|--recursive]
<host-src0> [host-src1 [...]] <guest-dst> copyto [common-options]
[--dryrun] [--follow] [-R|--recursive]
[--target-directory <guest-dst>]
<host-src0> [host-src1 [...]] mkdir|createdir[ectory] [common-options]
[--parents] [--mode <mode>]
<guest directory> [...] rmdir|removedir[ectory] [common-options]

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[-R|--recursive]
<guest directory> [...] removefile|rm [common-options] [-f|--force]
<guest file> [...] mv|move|ren[ame] [common-options]
<source> [source1 [...]] <dest> mktemp|createtemp[orary] [common-options]
[--secure] [--mode <mode>] [--tmpdir <directory>]
<template>
stat [common-options]
<file> [...] guestcontrol <uuid|vmname> [--verbose|-v] [--quiet|-q] list <all|sessions|processes|files> [common-opts] closeprocess [common-options]
<
--session-id <ID>
| --session-name <name or pattern>
<PID1> [PID1 [...]] closesession [common-options]
< --all | --session-id <ID>
| --session-name <name or pattern> > updatega|updateguestadditions|updateadditions [--source <guest additions .ISO>]
[--wait-start] [common-options]
[-- [<argument1>] ... [<argumentN>]] watch [common-options]

debugvm

<uuid|vmname> dumpguestcore --filename <name> | info <item> [args] | injectnmi | log [--release|--debug] <settings> ...| logdest [--release|--debug] <settings> ...| logflags [--release|--debug] <settings> ...| osdetect | osinfo | osdmesg [--lines|-n <N>] | getregisters [--cpu <id>] <reg>|all ... | setregisters [--cpu <id>] <reg>=<value> ... | show [--human-readable|--sh-export|--sh-eval|
--cmd-set]
<logdbg-settings|logrel-settings>
[[opt] what ...] | statistics [--reset] [--pattern <pattern>]
[--descriptions]

metrics

list [*|host|<vmname> [<metric_list>]]
(comma-separated)

metrics

setup
[--period <seconds>] (default: 1)
[--samples <count>] (default: 1)
[--list]
[*|host|<vmname> [<metric_list>]]

metrics

query [*|host|<vmname> [<metric_list>]]

metrics

enable

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[--list]
[*|host|<vmname> [<metric_list>]] metrics disable
[--list]
[*|host|<vmname> [<metric_list>]]

metrics

collect
[--period <seconds>] (default: 1)
[--samples <count>] (default: 1)
[--list]
[--detach]
[*|host|<vmname> [<metric_list>]]

natnetwork

add --netname <name>
--network <network>
[--enable|--disable]
[--dhcp on|off]
[--port-forward-4 <rule>]
[--loopback-4 <rule>]
[--ipv6 on|off]
[--port-forward-6 <rule>]
[--loopback-6 <rule>]

natnetwork

remove --netname <name>

natnetwork

modify --netname <name>
[--network <network>]
[--enable|--disable]
[--dhcp on|off]
[--port-forward-4 <rule>]
[--loopback-4 <rule>]
[--ipv6 on|off]
[--port-forward-6 <rule>]
[--loopback-6 <rule>]

natnetwork

start --netname <name>

natnetwork

stop --netname <name>

hostonlyif

ipconfig <name>
[--dhcp |
--ip<ipv4> [--netmask<ipv4> (def: 255.255.255.0)] |
--ipv6<ipv6> [--netmasklengthv6<length> (def: 64)]] create | remove <name>

dhcpserver

add|modify --netname <network_name> |
--ifname <hostonly_if_name>
[--ip <ip_address>
--netmask <network_mask>
--lowerip <lower_ip>
--upperip <upper_ip>]
[--enable | --disable]

dhcpserver

remove --netname <network_name> |
--ifname <hostonly_if_name>

VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage

debugvm debugvm debugvm debugvm debugvm debugvm debugvm debugvm debugvm debugvm <uuid|vmname>
<uuid|vmname>
<uuid|vmname>
<uuid|vmname>
<uuid|vmname>
<uuid|vmname>
<uuid|vmname>
<uuid|vmname>
<uuid|vmname>
<uuid|vmname>

dumpvmcore [--filename=name] info <item> [args...] injectnmi log [[--release] | [--debug]] [group-settings...] logdest [[--release] | [--debug]] [destinations...] logflags [[--release] | [--debug]] [flags...] osdetect osinfo osdmesg [--lines=lines] getregisters [--cpu=id] [reg-set.reg-name...]

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VBoxManage debugvm <uuid|vmname> setregisters [--cpu=id] [reg-set.reg-name=value...]
VBoxManage debugvm <uuid|vmname> show [[--human-readable] | [--sh-export] | [--sh-eval] | [--cmd-set]]
[settings-item...]
VBoxManage debugvm <uuid|vmname> statistics [--reset] [--descriptions] [--pattern=pattern]
VBoxManage extpack install [--replace] <tarball>
VBoxManage extpack uninstall [--force] <name>
VBoxManage extpack cleanup

Each time VBoxManage is invoked, only one command can be executed. However, a command might support several subcommands which then can be invoked in one single call. The following sections provide detailed reference information on the different commands.

8.3 General options
• --version: show the version of this tool and exit.
• --nologo: suppress the output of the logo information (useful for scripts)
• --settingspw: speciﬁy a settings password
• --settingspwfile: specify a ﬁle containing the settings password.
The settings password is used for certain settings which need to be stored encrypted for security reasons. At the moment, the only encrypted setting is the iSCSI initiator secret (see chapter
8.18, VBoxManage storageattach, page 144 for details). As long as no settings password is speciﬁed, this information is stored in plain text. After using the --settingspw|--settingspwfile option once, it must be always used, otherwise the encrypted setting cannot be unencrypted.

8.4 VBoxManage list
The list command gives relevant information about your system and information about
VirtualBox’s current settings.
The following subcommands are available with VBoxManage list:
• vms lists all virtual machines currently registered with VirtualBox. By default this displays a compact list with each VM’s name and UUID; if you also specify --long or -l, this will be a detailed list as with the showvminfo command (see below).
• runningvms lists all currently running virtual machines by their unique identiﬁers (UUIDs) in the same format as with vms.
• ostypes lists all guest operating systems presently known to VirtualBox, along with the identiﬁers used to refer to them with the modifyvm command.
• hostdvds, hostfloppies, respectively, list DVD, ﬂoppy, bridged networking and host-only networking interfaces on the host, along with the name used to access them from within
VirtualBox.
• bridgedifs, hostonlyifs and dhcpservers, respectively, list bridged network interfaces, host-only network interfaces and DHCP servers currently available on the host. Please see chapter 6, Virtual networking, page 94 for details on these.
• hostinfo displays information about the host system, such as CPUs, memory size and operating system version.

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• hostcpuids dumps the CPUID parameters for the host CPUs. This can be used for a more ﬁne grained analyis of the host’s virtualization capabilities.
• hddbackends lists all known virtual disk back-ends of VirtualBox. For each such format
(such as VDI, VMDK or RAW), this lists the back-end’s capabilities and conﬁguration.
• hdds, dvds and floppies all give you information about virtual disk images currently in use by VirtualBox, including all their settings, the unique identiﬁers (UUIDs) associated with them by VirtualBox and all ﬁles associated with them. This is the command-line equivalent of the Virtual Media Manager; see chapter 5.3, The Virtual Media Manager, page
85.
• usbhost supplies information about USB devices attached to the host, notably information useful for constructing USB ﬁlters and whether they are currently in use by the host.
• usbfilters lists all global USB ﬁlters registered with VirtualBox – that is, ﬁlters for devices which are accessible to all virtual machines – and displays the ﬁlter parameters.
• systemproperties displays some global VirtualBox settings, such as minimum and maximum guest RAM and virtual hard disk size, folder settings and the current authentication library in use.
• extpacks displays all VirtualBox extension packs currently installed; see chapter 1.5, Installing VirtualBox and extension packs, page 15 and chapter 8.36, VBoxManage extpack, page 169 for more information.

8.5 VBoxManage showvminfo
The showvminfo command shows information about a particular virtual machine. This is the same information as VBoxManage list vms --long would show for all virtual machines.
You will get information similar to the following:
$ VBoxManage showvminfo "Windows XP"
VirtualBox Command Line Management Interface Version 5.0.0
(C) 2005-2015 Oracle Corporation
All rights reserved.
Name:
Windows XP
Guest OS:
Other/Unknown
UUID:
1bf3464d-57c6-4d49-92a9-a5cc3816b7e7
Config file:
/home/username/.config/VirtualBox/Machines/Windows XP/Windows XP.xml
Memory size:
512MB
VRAM size:
12MB
Number of CPUs: 2
Synthetic Cpu: off Boot menu mode: message and menu
Boot Device (1): DVD
Boot Device (2): HardDisk
Boot Device (3): Not Assigned
Boot Device (4): Not Assigned
ACPI:
on
IOAPIC:
on
PAE:
on
Time offset:
0 ms
Hardw. virt.ext: on
Nested Paging: on VT-x VPID: off State: powered off (since 2009-10-20T14:52:19.000000000)
Monitor count:
1
3D Acceleration: off
2D Video Acceleration: off

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Teleporter Enabled: off
Teleporter Port: 0
Teleporter Address:
Teleporter Password:
Storage Controller
(0): IDE Controller
Storage Controller Type (0): PIIX4
Storage Controller
(1): Floppy Controller 1
Storage Controller Type (1): I82078
IDE Controller (0, 0): /home/user/windows.vdi (UUID: 46f6e53a-4557-460a-9b95-68b0f17d744b)
IDE Controller (0, 1): /home/user/openbsd-cd46.iso (UUID: 4335e162-59d3-4512-91d5-b63e94eebe0b)
Floppy Controller 1 (0, 0): /home/user/floppy.img (UUID: 62ac6ccb-df36-42f2-972e-22f836368137)
NIC 1: disabled NIC 2: disabled NIC 3: disabled NIC 4: disabled NIC 5: disabled NIC 6: disabled NIC 7: disabled NIC 8: disabled UART 1: disabled UART 2: disabled Audio: disabled (Driver: Unknown)
Clipboard Mode: Bidirectional
VRDE:
disabled
USB:
disabled
USB Device Filters:
<none>
Shared folders:
<none>
Statistics update:

disabled

8.6 VBoxManage registervm / unregistervm
The registervm command allows you to import a virtual machine deﬁnition in an XML ﬁle into
VirtualBox. The machine must not conﬂict with one already registered in VirtualBox and it may not have any hard or removable disks attached. It is advisable to place the deﬁnition ﬁle in the machines folder before registering it.
Note: When creating a new virtual machine with VBoxManage createvm (see below), you can directly specify the --register option to avoid having to register it separately.
The unregistervm command unregisters a virtual machine. If --delete is also speciﬁed, the following ﬁles will automatically be deleted as well:
1. all hard disk image ﬁles, including differencing ﬁles, which are used by the machine and not shared with other machines;
2. saved state ﬁles that the machine created, if any (one if the machine was in “saved” state and one for each online snapshot);
3. the machine XML ﬁle and its backups;
4. the machine log ﬁles, if any;
5. the machine directory, if it is empty after having deleted all the above.

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8.7 VBoxManage createvm
This command creates a new XML virtual machine deﬁnition ﬁle.
The --name <name> parameter is required and must specify the name of the machine. Since this name is used by default as the ﬁle name of the settings ﬁle (with the extension .xml) and the machine folder (a subfolder of the .config/VirtualBox/Machines folder - this folder name may vary depending on the operating system and the version of VirtualBox which you are using), it must conform to your host operating system’s requirements for ﬁle name speciﬁcations. If the
VM is later renamed, the ﬁle and folder names will change automatically.
However, if the --basefolder <path> option is used, the machine folder will be named
<path>. In this case, the names of the ﬁle and the folder will not change if the virtual machine is renamed.
By default, this command only creates the XML ﬁle without automatically registering the VM with your VirtualBox installation. To register the VM instantly, use the optional --register option, or run VBoxManage registervm separately afterwards.

8.8 VBoxManage modifyvm
This command changes the properties of a registered virtual machine which is not running.
Most of the properties that this command makes available correspond to the VM settings that
VirtualBox graphical user interface displays in each VM’s “Settings” dialog; these were described in chapter 3, Conﬁguring virtual machines, page 43. Some of the more advanced settings, however, are only available through the VBoxManage interface.
These commands require that the machine is powered off (neither running nor in “saved” state). Some machine settings can also be changed while a machine is running; those settings will then have a corresponding subcommand with the VBoxManage controlvm subcommand
(see chapter 8.13, VBoxManage controlvm, page 140).

8.8.1 General settings
The following general settings are available through VBoxManage modifyvm:
• --name <name>: This changes the VM’s name and possibly renames the internal virtual machine ﬁles, as described with VBoxManage createvm above.
• --groups <group>, ...: This changes the group membership of a VM. Groups always start with a / and can be nested. By default VMs are in group /.
• --description <desc>: This changes the VM’s description, which is a way to record details about the VM in a way which is meaningful for the user. The GUI interprets HTML formatting, the command line allows arbitrary strings potentially containing multiple lines.
• --ostype <ostype>: This speciﬁes what guest operating system is supposed to run in the
VM. To learn about the various identiﬁers that can be used here, use VBoxManage list ostypes. • --memory <memorysize>: This sets the amount of RAM, in MB, that the virtual machine should allocate for itself from the host. See the remarks in chapter 1.7, Creating your ﬁrst virtual machine, page 17 for more information.
• --vram <vramsize>: This sets the amount of RAM that the virtual graphics card should have. See chapter 3.5, Display settings, page 50 for details.
• --acpi on|off; --ioapic on|off: These two determine whether the VM should have
ACPI and I/O APIC support, respectively; see chapter 3.4.1, “Motherboard” tab, page 47 for details. 129

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• --hardwareuuid <uuid>: The UUID presented to the guest via memory tables
(DMI/SMBIOS), hardware and guest properties. By default this is the same as the VM uuid. Useful when cloning a VM. Teleporting takes care of this automatically.
• --cpus <cpucount>: This sets the number of virtual CPUs for the virtual machine (see chapter 3.4.2, “Processor” tab, page 49). If CPU hot-plugging is enabled (see below), this then sets the maximum number of virtual CPUs that can be plugged into the virtual machines.
• --cpuhotplug on|off: This enables CPU hot-plugging. When enabled, virtual CPUs can be added to and removed from a virtual machine while it is running. See chapter 9.5, CPU hot-plugging, page 179 for more information.
• --plugcpu|unplugcpu <id>: If CPU hot-plugging is enabled (see above), this adds a virtual CPU to the virtual machines (or removes one). <id> speciﬁes the index of the virtual CPU to be added or removed and must be a number from 0 to the maximum no. of
CPUs conﬁgured with the --cpus option. CPU 0 can never be removed.
• --cpuexecutioncap <1-100>: This setting controls how much cpu time a virtual CPU can use. A value of 50 implies a single virtual CPU can use up to 50% of a single host CPU.
• --pae on|off: This enables/disables PAE (see chapter 3.4.2, “Processor” tab, page 49).
• --longmode on|off: This enables/disables long mode (see chapter 3.4.2, “Processor” tab, page 49).
• --synthcpu on|off: This setting determines whether VirtualBox will expose a synthetic
CPU to the guest to allow live migration between host systems that differ signiﬁcantly.
• --hpet on|off: This enables/disables a High Precision Event Timer (HPET) which can replace the legacy system timers. This is turned off by default. Note that Windows supports a HPET only from Vista onwards.
• --hwvirtex on|off: This enables or disables the use of hardware virtualization extensions (Intel VT-x or AMD-V) in the processor of your host system; see chapter 10.3, Hardware vs. software virtualization, page 219.
• --triplefaultreset on|off: This setting allows to reset the guest instead of triggering a Guru Meditation. Some guests raise a triple fault to reset the CPU so sometimes this is desired behavior. Works only for non-SMP guests.
• --paravirtprovider none|default|legacy|minimal|hyperv|kvm: This setting speciﬁes which paravirtualization interface to provide to the guest operating system. Specifying none explicitly turns off exposing any paravirtualization interface. The option default, will pick an appropriate interface depending on the guest OS type while starting the VM.
This is the default option chosen while creating new VMs. The legacy option is chosen for
VMs which were created with older VirtualBox versions and will pick a paravirtualization interface while starting the VM with VirtualBox 5.0 and newer. The minimal provider is mandatory for Mac OS X guests, while kvm and hyperv are recommended for Linux and
Windows guests respectively. These options are explained in detail under chapter 10.4,
Paravirtualization providers, page 220.
• --nestedpaging on|off: If hardware virtualization is enabled, this additional setting enables or disables the use of the nested paging feature in the processor of your host system; see chapter 10.3, Hardware vs. software virtualization, page 219.
• --largepages on|off: If hardware virtualization and nested paging are enabled, for Intel
VT-x only, an additional performance improvement of up to 5% can be obtained by enabling this setting. This causes the hypervisor to use large pages to reduce TLB use and overhead.

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• --vtxvpid on|off: If hardware virtualization is enabled, for Intel VT-x only, this additional setting enables or disables the use of the tagged TLB (VPID) feature in the processor of your host system; see chapter 10.3, Hardware vs. software virtualization, page 219.
• --vtxux on|off: If hardware virtualization is enabled, for Intel VT-x only, this setting enables or disables the use of the unrestricted guest mode feature for executing your guest.
• --accelerate3d on|off: This enables, if the Guest Additions are installed, whether hardware 3D acceleration should be available; see chapter 4.5.1, Hardware 3D acceleration
(OpenGL and Direct3D 8/9), page 73.
• --accelerate2dvideo on|off: This enables, if the Guest Additions are installed, whether 2D video acceleration should be available; see chapter 4.5.2, Hardware 2D video acceleration for Windows guests, page 75.
• --chipset piix3|ich9: By default VirtualBox emulates an Intel PIIX3 chipset. Usually there is no reason to change the default setting unless it is required to relax some of its constraints; see chapter 3.4.1, “Motherboard” tab, page 47.
• You can inﬂuence the BIOS logo that is displayed when a virtual machine starts up with a number of settings. Per default, a VirtualBox logo is displayed.
With --bioslogofadein on|off and --bioslogofadeout on|off, you can determine whether the logo should fade in and out, respectively.
With --bioslogodisplaytime <msec> you can set how long the logo should be visible, in milliseconds.
With --bioslogoimagepath <imagepath> you can, if you are so inclined, replace the image that is shown, with your own logo. The image must be an uncompressed 256 color
BMP ﬁle without color space information (Windows 3.0 format). The image must not be bigger than 640 x 480.
• --biosbootmenu disabled|menuonly|messageandmenu: This speciﬁes whether the
BIOS allows the user to select a temporary boot device. menuonly suppresses the message, but the user can still press F12 to select a temporary boot device.
• --nicbootprio<1-N> <priority>: This speciﬁes the order in which NICs are tried for booting over the network (using PXE). The priority is an integer in the 0 to 4 range. Priority
1 is the highest, priority 4 is low. Priority 0, which is the default unless otherwise speciﬁed, is the lowest.
Note that this option only has effect when the Intel PXE boot ROM is used.
• --biospxedebug on|off: This option enables additional debugging output when using the Intel PXE boot ROM. The output will be written to the release log ﬁle (chapter 12.1.2,
Collecting debugging information, page 227.
• --boot<1-4> none|floppy|dvd|disk|net: This speciﬁes the boot order for the virtual machine. There are four “slots”, which the VM will try to access from 1 to 4, and for each of which you can set a device that the VM should attempt to boot from.
• --rtcuseutc on|off: This option lets the real-time clock (RTC) operate in UTC time (see chapter 3.4.1, “Motherboard” tab, page 47).
• --biossystemtimeoffset <ms>: This allows you to set a ﬁxed time offset of the guest relative to the host time. The offset is speciﬁed in milliseconds. If the offset is positive the guest time runs ahead the host time.
• --snapshotfolder default|<path>: This allows you to specify the folder in which snapshots will be kept for a virtual machine.

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• --firmware efi|bios: Speciﬁes which ﬁrmware is used to boot particular virtual machine: EFI or BIOS. Use EFI only if your fully understand what you’re doing.
• --guestmemoryballoon <size> sets the default size of the guest memory balloon, that is, memory allocated by the VirtualBox Guest Additions from the guest operating system and returned to the hypervisor for re-use by other virtual machines. <size> must be speciﬁed in megabytes. The default size is 0 megabytes. For details, see chapter 4.9.1, Memory ballooning, page 78.
• --defaultfrontend default|<name>: This allows you to specify the default frontend which will be used when starting this VM; see chapter 8.12, VBoxManage startvm, page
140 for details.

8.8.2 Networking settings
The following networking settings are available through VBoxManage modifyvm. With all these settings, the decimal number directly following the option name (“1-N” in the list below) speciﬁes the virtual network adapter whose settings should be changed.
• --nic<1-N> none|null|nat|natnetwork|bridged|intnet|hostonly|generic: With this, you can set, for each of the VM’s virtual network cards, what type of networking should be available. They can be not present (none), not connected to the host (null), use network address translation (nat), use the new network address translation engine
(natnetwork), bridged networking (bridged) or communicate with other virtual machines using internal networking (intnet), host-only networking (hostonly), or access rarely used sub-modes (generic). These options correspond to the modes which are described in detail in chapter 6.2, Introduction to networking modes, page 95.
• --nicpromisc<1-N> deny|allow-vms|allow-all: This allows you, for each of the VM’s virtual network cards, to specify how the promiscious mode is handled. This setting is only relevant for bridged networking. deny (default setting) hides any trafﬁc not intended for this VM. allow-vms hides all host trafﬁc from this VM but allows the VM to see trafﬁc from/to other VMs. allow-all removes this restriction completely.
• --nictype<1-N> Am79C970A|Am79C973|82540EM|82543GC|82545EM|virtio: This allows you, for each of the VM’s virtual network cards, to specify which networking hardware
VirtualBox presents to the guest; see chapter 6.1, Virtual networking hardware, page 94.
• --cableconnected<1-N> on|off: This allows you to temporarily disconnect a virtual network interface, as if a network cable had been pulled from a real network card. This might be useful for resetting certain software components in the VM.
• With the “nictrace” options, you can optionally trace network trafﬁc by dumping it to a ﬁle, for debugging purposes.
With --nictrace<1-N> on|off, you can enable network tracing for a particular virtual network card.
If enabled, you must specify with --nictracefile<1-N> <filename> what ﬁle the trace should be logged to.
• --natnet<1-N> <network>|default: If the networking type is set to nat (not natnetwork) then this setting speciﬁes the IP address range to be used for this network.
See chapter 9.11, Fine-tuning the VirtualBox NAT engine, page 187 for an example.
• --nat-network<1-N> <network name>: If the networking type is set to natnetwork (not nat) then this setting speciﬁes the name of the NAT network this adapter is connected to.

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• --bridgeadapter<1-N> none|<devicename>: If bridged networking has been enabled for a virtual network card (see the --nic option above; otherwise this setting has no effect), use this option to specify which host interface the given virtual network interface will use. For details, please see chapter 6.5, Bridged networking, page 99.
• --hostonlyadapter<1-N> none|<devicename>: If host-only networking has been enabled for a virtual network card (see the –nic option above; otherwise this setting has no effect), use this option to specify which host-only networking interface the given virtual network interface will use. For details, please see chapter 6.7, Host-only networking, page
101.
• --intnet<1-N> network: If internal networking has been enabled for a virtual network card (see the --nic option above; otherwise this setting has no effect), use this option to specify the name of the internal network (see chapter 6.6, Internal networking, page 100).
• --macaddress<1-N> auto|<mac>: With this option you can set the MAC address of the virtual network card. Normally, each virtual network card is assigned a random address by
VirtualBox at VM creation.
• --nicgenericdrv<1-N> <backend driver>: If generic networking has been enabled for a virtual network card (see the --nic option above; otherwise this setting has no effect), this mode allows you to access rarely used networking sub-modes, such as VDE network or
UDP Tunnel.
• --nicproperty<1-N> <paramname>="paramvalue": This option, in combination with
“nicgenericdrv” allows you to pass parameters to rarely-used network backends.
Those parameters are backend engine-speciﬁc, and are different between UDP Tunnel and the VDE backend drivers. For example, please see chapter 6.8, UDP Tunnel networking, page 102.
8.8.2.1 NAT Networking settings.
The following NAT networking settings are available through VBoxManage modifyvm. With all these settings, the decimal number directly following the option name (“1-N” in the list below) speciﬁes the virtual network adapter whose settings should be changed.
• --natpf<1-N> [<name>],tcp|udp,[<hostip>],<hostport>,[<guestip>], <guestport>:
This option deﬁnes a NAT port-forwarding rule (please see chapter 6.3.1, Conﬁguring port forwarding with NAT, page 96 for details).
• --natpf<1-N> delete <name>: This option deletes a NAT port-forwarding rule (please see chapter 6.3.1, Conﬁguring port forwarding with NAT, page 96 for details).
• --nattftpprefix<1-N> <prefix>: This option deﬁnes a preﬁx for the built-in TFTP server, i.e. where the boot ﬁle is located (please see chapter 6.3.2, PXE booting with NAT, page 97 and chapter 9.11.2, Conﬁguring the boot server (next server) of a NAT network interface, page 188 for details).
• --nattftpfile<1-N> <bootfile>: This option deﬁnes the TFT boot ﬁle (please see chapter 9.11.2, Conﬁguring the boot server (next server) of a NAT network interface, page 188 for details). • --nattftpserver<1-N> <tftpserver>: This option deﬁnes the TFTP server address to boot from (please see chapter 9.11.2, Conﬁguring the boot server (next server) of a NAT network interface, page 188 for details).
• --natdnspassdomain<1-N> on|off: This option speciﬁes whether the built-in DHCP server passes the domain name for network name resolution.

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• --natdnsproxy<1-N> on|off: This option makes the NAT engine proxy all guest DNS requests to the host’s DNS servers (please see chapter 9.11.5, Enabling DNS proxy in NAT mode, page 188 for details).
• --natdnshostresolver<1-N> on|off: This option makes the NAT engine use the host’s resolver mechanisms to handle DNS requests (please see chapter 9.11.5, Enabling DNS proxy in NAT mode, page 188 for details).
• --natsettings<1-N> [<mtu>],[<socksnd>],[<sockrcv>],[<tcpsnd>], [<tcprcv>]:
This option controls several NAT settings (please see chapter 9.11.3, Tuning TCP/IP buffers for NAT, page 188 for details).
• --nataliasmode<1-N> default|[log],[proxyonly],[sameports]: This option deﬁnes behaviour of NAT engine core: log - enables logging, proxyonly - switches of aliasing mode makes NAT transparent, sameports enforces NAT engine to send packets via the same port as they originated on, default - disable all mentioned modes above . (please see chapter 9.11.7, Conﬁguring aliasing of the NAT engine, page 189 for details).

8.8.3 Miscellaneous settings
The following other hardware settings, such as serial port, audio, clipboard, drag’n drop, monitor and USB settings are available through VBoxManage modifyvm:
• --uart<1-N> off|<I/O base> <IRQ>: With this option you can conﬁgure virtual serial ports for the VM; see chapter 3.9, Serial ports, page 53 for an introduction.
• --uartmode<1-N> <arg>: This setting controls how VirtualBox connects a given virtual serial port (previously conﬁgured with the --uartX setting, see above) to the host on which the virtual machine is running. As described in detail in chapter 3.9, Serial ports, page 53, for each such port, you can specify <arg> as one of the following options:
– disconnected: Even though the serial port is shown to the guest, it has no “other end” – like a real COM port without a cable.
– server <pipename>: On a Windows host, this tells VirtualBox to create a named pipe on the host named <pipename> and connect the virtual serial device to it. Note that Windows requires that the name of a named pipe begin with \\.\pipe\.
On a Linux host, instead of a named pipe, a local domain socket is used.
– client <pipename>: This operates just like server ..., except that the pipe (or local domain socket) is not created by VirtualBox, but assumed to exist already.
– tcpserver <port>: This tells VirtualBox to create a TCP socket on the host with TCP
<port> and connect the virtual serial device to it. Note that UNIX-like systems require ports over 1024 for normal users.
– tcpclient <hostname:port>: This operates just like tcpserver ..., except that the TCP socket is not created by VirtualBox, but assumed to exist already.
– <devicename>: If, instead of the above, the device name of a physical hardware serial port of the host is speciﬁed, the virtual serial port is connected to that hardware port.
On a Windows host, the device name will be a COM port such as COM1; on a Linux host, the device name will look like /dev/ttyS0. This allows you to “wire” a real serial port to a virtual machine.
• --lptmode<1-N> <Device>: Speciﬁes the Device Name of the parallel port that the Parallel Port feature will be using. Use this before --lpt. This feature is host operating system speciﬁc. 134

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• --lpt<1-N> <I/O base> <IRQ>: Speciﬁes the I/O address of the parallel port and the
IRQ number that the Parallel Port feature will be using. Use this after --lptmod. I/O base address and IRQ are the values that guest sees i.e. the values avalable under guest Device
Manager.
• --audio none|null|oss: With this option, you can set whether the VM should have audio support.
• --clipboard disabled|hosttoguest|guesttohost|bidirectional: With this setting, you can select if and how the guest or host operating system’s clipboard should be shared with the host or guest; see chapter 3.3, General settings, page 46. This requires that the Guest Additions be installed in the virtual machine.
• --draganddrop disabled|hosttoguest|guesttohost|bidirectional: With this setting, you can select the current drag’n drop mode being used between the host and the virtual machine; see chapter 4.4, Drag’n Drop, page 72. This requires that the Guest Additions be installed in the virtual machine.
• --monitorcount <count>: This enables multi-monitor support; see chapter 3.5, Display settings, page 50.
• --usb on|off: This option enables or disables the VM’s virtual USB controller; see chapter
3.10.1, USB settings, page 55 for details.
• --usbehci on|off: This option enables or disables the VM’s virtual USB 2.0 controller; see chapter 3.10.1, USB settings, page 55 for details.
• --usbxhci on|off: This option enables or disables the VM’s virtual USB 3.0 controller; see chapter 3.10.1, USB settings, page 55 for details.

8.8.4 Video Capture settings
The following settings for changing video recording parameters are available through
VBoxManage modifyvm.
• --videocap on|off: This option enables or disables recording a VM session into a
WebM/VP8 ﬁle. If this option is enabled, recording will start when the VM session is started. • --videocapscreens all|<screen ID> [<screen ID> ...]: This option allows to specify which screens of the VM are being recorded. Each screen is recorded into a separate ﬁle.
• --videocapfile <filename>: This option sets the ﬁlename VirtualBox uses to save the recorded content.
• --videocapres <width>x<height>: This option sets the resolution (in pixels) of the recorded video.
• --videocaprate <rate>: This option sets the bitrate in kilobits (kb) per second. Increasing this value makes the video look better for the cost of an increased ﬁle size.
• --videocapfps <fps>: This option sets the maximum number of frames per second (FPS) to be recorded. Frames with a higher frequency will be skipped. Reducing this value increases the number of skipped frames and reduces the ﬁle size.
• --videocapmaxtime <ms>: This option sets the maximum time in milliseconds the video capturing will be enabled since activation. The capturing stops when the deﬁned time interval has elapsed. If this value is zero the capturing is not limited by time.

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• --videocapmaxsize <MB>: This option limits the maximum size of the captured video ﬁle
(in MB). The capturing stops when the ﬁle size has reached the speciﬁed size. If this value is zero the capturing will not be limited by ﬁle size.
• --videocapopts <key=value> [,<key=value> ...]: This format can be used to specify additional video capturing options. These options only are for advanced users and must be speciﬁed in a comma-separated key=value format, e.g. foo=bar,a=b.

8.8.5 Remote machine settings
The following settings that affect remote machine behavior are available through VBoxManage modifyvm: • --vrde on|off: This enables or disables the VirtualBox remote desktop extension (VRDE) server. • --vrdeextpack default|<name>: Allows to specify the library to use for to access the
VM remotely. The default is to use the RDP code which is part of the Oracle VM VirtualBox
Extension Pack.
• --vrdeport default|<ports>: A port or a range of ports the VRDE server can bind to;
“default” or “0” means port 3389, the standard port for RDP. You can specify a commaseparated list of ports or ranges of ports. Use a dash between two port numbers to specify a range. The VRDE server will bind to one of available ports from the speciﬁed list.
Only one machine can use a given port at a time. For example, the option --vrdeport
5000,5010-5012 will tell the server to bind to one of following ports: 5000, 5010, 5011 or 5012.
• --vrdeaddress <IP address>: The IP address of the host network interface the VRDE server will bind to. If speciﬁed, the server will accept connections only on the speciﬁed host network interface.
The setting can be used to specify whether the VRDP server should accept either IPv4 or
IPv6 or both connections:
– only IPv4: --vrdeaddress "0.0.0.0"
– only IPv6: --vrdeaddress "::"
– both IPv6 and IPv4 (default): --vrdeaddress ""
• --vrdeauthtype null|external|guest: This allows you to choose whether and how authorization will be performed; see chapter 7.1.5, RDP authentication, page 109 for details.
• --vrdeauthlibrary default|<name>: This allos to set the library used for RDP authentication, see chapter 7.1.5, RDP authentication, page 109 for details.
• --vrdemulticon on|off: This enables multiple connections to the same VRDE server, if the server supports this feature; see chapter 7.1.7, Multiple connections to the VRDP server, page 111.
• --vrdereusecon on|off: This speciﬁes the VRDE server behavior when multiple connections are disabled. When this option is enabled, the server will allow a new client to connect and will drop the existing connection. When this option is disabled (this is the default setting), a new connection will not be accepted if there is already a client connected to the server.
• --vrdevideochannel on|off: This enables video redirection, if it is supported by the
VRDE server; see chapter 7.1.9, VRDP video redirection, page 112.

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• --vrdevideochannelquality <percent>: Sets the image quality for video redirection; see chapter 7.1.9, VRDP video redirection, page 112.

8.8.6 Teleporting settings
With the following commands for VBoxManage modifyvm you can conﬁgure a machine to be a target for teleporting. See chapter 7.2, Teleporting, page 113 for an introduction.
• --teleporter on|off: With this setting you turn on or off whether a machine waits for a teleporting request to come in on the network when it is started. If “on”, when the machine is started, it does not boot the virtual machine as it would normally; instead, it then waits for a teleporting request to come in on the port and address listed with the next two parameters.
• --teleporterport <port>, --teleporteraddress <address>: these must be used with –teleporter and tell the virtual machine on which port and address it should listen for a teleporting request from another virtual machine. <port> can be any free TCP/IP port number (e.g. 6000); <address> can be any IP address or hostname and speciﬁes the
TCP/IP socket to bind to. The default is “0.0.0.0”, which means any address.
• --teleporterpassword <password>: if this optional argument is given, then the teleporting request will only succeed if the source machine speciﬁes the same password as the one given with this command.
• --teleporterpasswordfile <password>: if this optional argument is given, then the teleporting request will only succeed if the source machine speciﬁes the same password as the one speciﬁed in the ﬁle give with this command. Use stdin to read the password from stdin. • --cpuid <leaf> <eax> <ebx> <ecx> <edx>: Advanced users can use this command before a teleporting operation to restrict the virtual CPU capabilities that VirtualBox presents to the guest operating system. This must be run on both the source and the target machines involved in the teleporting and will then modify what the guest sees when it executes the
CPUID machine instruction. This might help with misbehaving applications that wrongly assume that certain CPU capabilities are present. The meaning of the parameters is hardware dependent; please refer to the AMD or Intel processor manuals.

8.8.7 Debugging settings
The following settings are only relevant for low-level VM debugging. Regular users will never need these settings.
• --tracing-enabled on|off: Enable the tracebuffer. This consumes some memory for the tracebuffer and adds extra overhead.
• --tracing-config <config-string>: Allows to conﬁgure tracing. In particular this deﬁnes which group of tracepoints are enabled.

8.9 VBoxManage clonevm
This command creates a full or linked copy of an existing virtual machine.
The clonevm subcommand takes at least the name of the virtual machine which should be cloned. The following additional settings can be used to further conﬁgure the clone VM operation:

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• --snapshot <uuid>|<name>: Select a speciﬁc snapshot where the clone operation should refer to. Default is referring to the current state.
• --mode machine|machineandchildren|all: Selects the cloning mode of the operation.
If machine is selected (the default), the current state of the VM without any snapshots is cloned. In the machineandchildren mode the snapshot provided by --snapshot and all child snapshots are cloned. If all is the selected mode all snapshots and the current state are cloned.
• --options link|keepallmacs|keepnatmacs|keepdisknames: Allows additional ﬁne tuning of the clone operation. The ﬁrst option deﬁnes that a linked clone should be created, which is only possible for a machine clone from a snapshot. The next two options allow to deﬁne how the MAC addresses of every virtual network card should be handled. They can either be reinitialized (the default), left unchanged (keepallmacs) or left unchanged when the network type is NAT (keepnatmacs). If you add keepdisknames all new disk images are called like the original ones, otherwise they are renamed.
• --name <name>: Select a new name for the new virtual machine. Default is “Original
Name Clone”.
• --basefolder <basefolder>: Select the folder where the new virtual machine conﬁguration should be saved in.
• --uuid <uuid>: Select the UUID the new VM should have. This id has to be unique in the
VirtualBox instance this clone should be registered. Default is creating a new UUID.
• --register: Automatically register the new clone in this VirtualBox installation. If you manually want to register the new VM later, see chapter 8.6, VBoxManage registervm / unregistervm, page 128 for instructions how to do so.

8.10 VBoxManage import
This command imports a virtual appliance in OVF format by copying the virtual disk images and creating virtual machines in VirtualBox. See chapter 1.14, Importing and exporting virtual machines, page 30 for an introduction to appliances.
The import subcommand takes at least the path name of an OVF ﬁle as input and expects the disk images, if needed, in the same directory as the OVF ﬁle. A lot of additional commandline options are supported to control in detail what is being imported and modify the import parameters, but the details depend on the content of the OVF ﬁle.
It is therefore recommended to ﬁrst run the import subcommand with the --dry-run or -n option. This will then print a description of the appliance’s contents to the screen how it would be imported into VirtualBox, together with the optional command-line options to inﬂuence the import behavior.
As an example, here is the screen output with a sample appliance containing a Windows XP guest: VBoxManage import WindowsXp.ovf --dry-run
Interpreting WindowsXp.ovf...
OK.
Virtual system 0:
0: Suggested OS type: "WindowsXP"
(change with "--vsys 0 --ostype <type>"; use "list ostypes" to list all)
1: Suggested VM name "Windows XP Professional_1"
(change with "--vsys 0 --vmname <name>")
3: Number of CPUs: 1
(change with "--vsys 0 --cpus <n>")
4: Guest memory: 956 MB (change with "--vsys 0 --memory <MB>")
5: Sound card (appliance expects "ensoniq1371", can change on import)

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(disable with "--vsys 0 --unit 5 --ignore")
6: USB controller
(disable with "--vsys 0 --unit 6 --ignore")
7: Network adapter: orig bridged, config 2, extra type=bridged
8: Floppy
(disable with "--vsys 0 --unit 8 --ignore")
9: SCSI controller, type BusLogic
(change with "--vsys 0 --unit 9 --scsitype {BusLogic|LsiLogic}"; disable with "--vsys 0 --unit 9 --ignore")
10: IDE controller, type PIIX4
(disable with "--vsys 0 --unit 10 --ignore")
11: Hard disk image: source image=WindowsXp.vmdk, target path=/home/user/disks/WindowsXp.vmdk, controller=9;channel=0
(change controller with "--vsys 0 --unit 11 --controller <id>"; disable with "--vsys 0 --unit 11 --ignore")

As you can see, the individual conﬁguration items are numbered, and depending on their type support different command-line options. The import subcommand can be directed to ignore many such items with a --vsys X --unit Y --ignore option, where X is the number of the virtual system (zero unless there are several virtual system descriptions in the appliance) and Y the item number, as printed on the screen.
In the above example, Item #1 speciﬁes the name of the target machine in VirtualBox. Items
#9 and #10 specify hard disk controllers, respectively. Item #11 describes a hard disk image; in this case, the additional --controller option indicates which item the disk image should be connected to, with the default coming from the OVF ﬁle.
You can combine several items for the same virtual system behind the same --vsys option. For example, to import a machine as described in the OVF, but without the sound card and without the USB controller, and with the disk image connected to the IDE controller instead of the SCSI controller, use this:
VBoxManage import WindowsXp.ovf
--vsys 0 --unit 5 --ignore --unit 6 --ignore --unit 11 --controller 10

8.11 VBoxManage export
This command exports one or more virtual machines from VirtualBox into a virtual appliance in
OVF format, including copying their virtual disk images to compressed VMDK. See chapter 1.14,
Importing and exporting virtual machines, page 30 for an introduction to appliances.
The export command is simple to use: list the machine (or the machines) that you would like to export to the same OVF ﬁle and specify the target OVF ﬁle after an additional --output or -o option. Note that the directory of the target OVF ﬁle will also receive the exported disk images in the compressed VMDK format (regardless of the original format) and should have enough disk space left for them.
Beside a simple export of a given virtual machine, you can append several product information to the appliance ﬁle. Use --product, --producturl, --vendor, --vendorurl and --version to specify this additional information. For legal reasons you may add a license text or the content of a license ﬁle by using the --eula and --eulafile option respectively. As with OVF import, you must use the --vsys X option to direct the previously mentioned options to the correct virtual machine.
For virtualization products which aren’t fully compatible with the OVF standard 1.0 you can enable a OVF 0.9 legacy mode with the --legacy09 option.
To specify options controlling the exact content of the appliance ﬁle, you can use --option to request the creation of a manifest ﬁle (encouraged, allows detection of corrupted appliances on import), the additional export of DVD images, and the exclusion of MAC addresses. You can specify a list of options, e.g. --option manifest,nomacs. For details, check the help output of
VBoxManage export.

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8.12 VBoxManage startvm
This command starts a virtual machine that is currently in the “Powered off” or “Saved” states.
The optional --type speciﬁer determines whether the machine will be started in a window or whether the output should go through VBoxHeadless, with VRDE enabled or not; see chapter
7.1.2, VBoxHeadless, the remote desktop server, page 106 for more information. The list of types is subject to change, and it’s not guaranteed that all types are accepted by any product variant.
The global or per-VM default value for the VM frontend type will be taken if the type is not explicitly speciﬁed. If none of these are set, the GUI variant will be started.
The following values are allowed: gui Starts a VM showing a GUI window. This is the default. headless Starts a VM without a window for remote display only. sdl Starts a VM with a minimal GUI and limited features. separate Starts a VM with detachable UI (technically it is a headless VM with user interface in

a separate process). This is an experimental feature as it lacks certain functionality at the moment (e.g. 3D acceleration will not work).

Note: If you experience problems with starting virtual machines with particular frontends and there is no conclusive error information, consider starting virtual machines directly by running the respective front-end, as this can give additional error information.

8.13 VBoxManage controlvm
The controlvm subcommand allows you to change the state of a virtual machine that is currently running. The following can be speciﬁed:
• VBoxManage controlvm <vm> pause temporarily puts a virtual machine on hold, without changing its state for good. The VM window will be painted in gray to indicate that the
VM is currently paused. (This is equivalent to selecting the “Pause” item in the “Machine” menu of the GUI.)
• Use VBoxManage controlvm <vm> resume to undo a previous pause command. (This is equivalent to selecting the “Resume” item in the “Machine” menu of the GUI.)
• VBoxManage controlvm <vm> reset has the same effect on a virtual machine as pressing the “Reset” button on a real computer: a cold reboot of the virtual machine, which will restart and boot the guest operating system again immediately. The state of the VM is not saved beforehand, and data may be lost. (This is equivalent to selecting the “Reset” item in the “Machine” menu of the GUI.)
• VBoxManage controlvm <vm> poweroff has the same effect on a virtual machine as pulling the power cable on a real computer. Again, the state of the VM is not saved beforehand, and data may be lost. (This is equivalent to selecting the “Close” item in the
“Machine” menu of the GUI or pressing the window’s close button, and then selecting
“Power off the machine” in the dialog.)
After this, the VM’s state will be “Powered off”. From there, it can be started again; see chapter 8.12, VBoxManage startvm, page 140.

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• VBoxManage controlvm <vm> savestate will save the current state of the VM to disk and then stop the VM. (This is equivalent to selecting the “Close” item in the “Machine” menu of the GUI or pressing the window’s close button, and then selecting “Save the machine state” in the dialog.)
After this, the VM’s state will be “Saved”. From there, it can be started again; see chapter
8.12, VBoxManage startvm, page 140.
• VBoxManage controlvm "VM name" teleport --hostname <name> --port <port>
[--passwordfile <file> | --password <password>] makes the machine the source of a teleporting operation and initiates a teleport to the given target. See chapter 7.2,
Teleporting, page 113 for an introduction. If the optional password is speciﬁed, it must match the password that was given to the modifyvm command for the target machine; see chapter 8.8.6, Teleporting settings, page 137 for details.
A few extra options are available with controlvm that do not directly affect the VM’s running state: • The setlinkstate<1-N> operation connects or disconnects virtual network cables from their network interfaces.
• nic<1-N> null|nat|bridged|intnet|hostonly|generic: With this, you can set, for each of the VM’s virtual network cards, what type of networking should be available. They can be not connected to the host (null), use network address translation (nat), bridged networking (bridged) or communicate with other virtual machines using internal networking (intnet) or host-only networking (hostonly) or access to rarely used sub-modes
(generic). These options correspond to the modes which are described in detail in chapter
6.2, Introduction to networking modes, page 95.
• With the “nictrace” options, you can optionally trace network trafﬁc by dumping it to a ﬁle, for debugging purposes.
With nictrace<1-N> on|off, you can enable network tracing for a particular virtual network card.
If enabled, you must specify with --nictracefile<1-N> <filename> what ﬁle the trace should be logged to.
• nicpromisc<1-N> deny|allow-vms|allow-all: This allows you, for each of the VM’s virtual network cards, to specify how the promiscious mode is handled. This setting is only relevant for bridged networking. deny (default setting) hides any trafﬁc not intended for this VM. allow-vms hides all host trafﬁc from this VM but allows the VM to see trafﬁc from/to other VMs. allow-all removes this restriction completely.
• nicproperty<1-N> <paramname>="paramvalue": This option, in combination with “nicgenericdrv” allows you to pass parameters to rarely-used network backends.
Those parameters are backend engine-speciﬁc, and are different between UDP Tunnel and the VDE backend drivers. For example, please see chapter 6.8, UDP Tunnel networking, page 102.
• The guestmemoryballoon operation changes the size of the guest memory balloon, that is, memory allocated by the VirtualBox Guest Additions from the guest operating system and returned to the hypervisor for re-use by other virtual machines. This must be speciﬁed in megabytes. For details, see chapter 4.9.1, Memory ballooning, page 78.
• usbattach and usbdettach make host USB devices visible to the virtual machine on the ﬂy, without the need for creating ﬁlters ﬁrst. The USB devices can be speciﬁed by UUID
(unique identiﬁer) or by address on the host system.
You can use VBoxManage list usbhost to locate this information.

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• clipboard disabled|hosttoguest|guesttohost|bidirectional: With this setting, you can select if and how the guest or host operating system’s clipboard should be shared with the host or guest; see chapter 3.3, General settings, page 46. This requires that the
Guest Additions be installed in the virtual machine.
• draganddrop disabled|hosttoguest|guesttohost|bidirectional: With this setting, you can select the current drag’n drop mode being used between the host and the virtual machine; see chapter 4.4, Drag’n Drop, page 72. This requires that the Guest
Additions be installed in the virtual machine.
• vrde on|off lets you enable or disable the VRDE server, if it is installed.
• vrdeport default|<ports> changes the port or a range of ports that the VRDE server can bind to; “default” or “0” means port 3389, the standard port for RDP. For details, see the description for the --vrdeport option in chapter 8.8.3, Miscellaneous settings, page
134.
• setvideomodehint requests that the guest system change to a particular video mode. This requires that the Guest Additions be installed, and will not work for all guest systems.
• screenshotpng takes a screenshot of the guest display and saves it in PNG format.
• videocap on|off enables or disables recording a VM session into a WebM/VP8 ﬁle.
• videocapscreens all|<screen ID> [<screen ID> ...]] allows to specify which screens of the VM are being recorded. This setting cannot be changed while video capturing is enabled. Each screen is recorded into a separate ﬁle.
• videocapfile <file> sets the ﬁlename VirtualBox uses to save the recorded content.
This setting cannot be changed while video capturing is enabled.
• videocapres <width> <height> sets the resolution (in pixels) of the recorded video.
This setting cannot be changed while video capturing is enabled.
• videocaprate <rate> sets the bitrate in kilobits (kb) per second. Increasing this value makes the video look better for the cost of an increased ﬁle size. This setting cannot be changed while video capturing is enabled.
• videocapfps <fps> sets the maximum number of frames per second (FPS) to be recorded.
Frames with a higher frequency will be skipped. Reducing this value increases the number of skipped frames and reduces the ﬁle size. This setting cannot be changed while video capturing is enabled.
• videocapmaxtime <ms> sets the maximum time in milliseconds the video capturing will be enabled since activation. The capturing stops when the deﬁned time interval has elapsed.
If this value is zero the capturing is not limited by time. This setting cannot be changed while video capturing is enabled.
• videocapmaxsize <MB> limits the maximum size of the captured video ﬁle (in MB). The capturing stops when the ﬁle size has reached the speciﬁed size. If this value is zero the capturing will not be limited by ﬁle size. This setting cannot be changed while video capturing is enabled.
• videocapopts <key=value>[,<key=value> ...] can be used to specify additional video capturing options. These options only are for advanced users and must be speciﬁed in a comma-separated key=value format, e.g. foo=bar,a=b. This setting cannot be changed while video capturing is enabled.

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• The setcredentials operation is used for remote logons in Windows guests. For details, please refer to chapter 9.2, Automated guest logons, page 173.
• plugcpu|unplugcpu <id>: If CPU hot-plugging is enabled, this adds a virtual CPU to the virtual machines (or removes one). <id> speciﬁes the index of the virtual CPU to be added or removed and must be a number from 0 to the maximum no. of CPUs conﬁgured. CPU 0 can never be removed.
• The cpuexecutioncap <1-100>: This operation controls how much cpu time a virtual
CPU can use. A value of 50 implies a single virtual CPU can use up to 50% of a single host
CPU.

8.14 VBoxManage discardstate
This command discards the saved state of a virtual machine which is not currently running, which will cause its operating system to restart next time you start it. This is the equivalent of pulling out the power cable on a physical machine, and should be avoided if possible.

8.15 VBoxManage adoptstate
If you have a saved state ﬁle (.sav) that is separate from the VM conﬁguration, you can use this command to “adopt” the ﬁle. This will change the VM to saved state and when you start it, VirtualBox will attempt to restore it from the saved state ﬁle you indicated. This command should only be used in special setups.

8.16 VBoxManage snapshot
This command is used to control snapshots from the command line. A snapshot consists of a complete copy of the virtual machine settings, copied at the time when the snapshot was taken, and optionally a virtual machine saved state ﬁle if the snapshot was taken while the machine was running. After a snapshot has been taken, VirtualBox creates differencing hard disk for each normal hard disk associated with the machine so that when a snapshot is restored, the contents of the virtual machine’s virtual hard disks can be quickly reset by simply dropping the pre-existing differencing ﬁles.
The take operation takes a snapshot of the current state of the virtual machine. You must supply a name for the snapshot and can optionally supply a description. The new snapshot is inserted into the snapshots tree as a child of the current snapshot and then becomes the new current snapshot. The --description parameter allows to describe the snapshot. If --live is speciﬁed, the VM will not be stopped during the snapshot creation (live smapshotting).
The delete operation deletes a snapshot (speciﬁed by name or by UUID). This can take a while to ﬁnish since the differencing images associated with the snapshot might need to be merged with their child differencing images.
The restore operation will restore the given snapshot (speciﬁed by name or by UUID) by resetting the virtual machine’s settings and current state to that of the snapshot. The previous current state of the machine will be lost. After this, the given snapshot becomes the new “current” snapshot so that subsequent snapshots are inserted under the snapshot from which was restored.
The restorecurrent operation is a shortcut to restore the current snapshot (i.e. the snapshot from which the current state is derived). This subcommand is equivalent to using the “restore” subcommand with the name or UUID of the current snapshot, except that it avoids the extra step of determining that name or UUID.
With the edit operation, you can change the name or description of an existing snapshot.

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With the showvminfo operation, you can view the virtual machine settings that were stored with an existing snapshot.

8.17 VBoxManage closemedium
This commands removes a hard disk, DVD or ﬂoppy image from a VirtualBox media registry.2
Optionally, you can request that the image be deleted. You will get appropriate diagnostics that the deletion failed, however the image will become unregistered in any case.

8.18 VBoxManage storageattach
This command attaches/modiﬁes/removes a storage medium connected to a storage controller that was previously added with the storagectl command (see the previous section). The syntax is as follows:
VBoxManage storageattach

<uuid|vmname>
--storagectl <name>
[--port <number>]
[--device <number>]
[--type dvddrive|hdd|fdd]
[--medium none|emptydrive|
<uuid>|<filename>|host:<drive>|iscsi]
[--mtype normal|writethrough|immutable|shareable]
[--comment <text>]
[--setuuid <uuid>]
[--setparentuuid <uuid>]
[--passthrough on|off]
[--tempeject on|off]
[--nonrotational on|off]
[--discard on|off]
[--bandwidthgroup name|none]
[--forceunmount]
[--server <name>|<ip>]
[--target <target>]
[--tport <port>]
[--lun <lun>]
[--encodedlun <lun>]
[--username <username>]
[--password <password>]
[--initiator <initiator>]
[--intnet]

A number of parameters are commonly required; the ones at the end of the list are required only for iSCSI targets (see below).
The common parameters are: uuid|vmname The VM UUID or VM Name. Mandatory.
--storagectl Name of the storage controller. Mandatory. The list of the storage controllers currently attached to a VM can be obtained with VBoxManage showvminfo; see chapter

8.5, VBoxManage showvminfo, page 127.
--port The number of the storage controller’s port which is to be modiﬁed. Mandatory, unless

the storage controller has only a single port.
2 Before

VirtualBox 4.0, it was necessary to call VBoxManage openmedium before a medium could be attached to a virtual machine; that call “registered” the medium with the global VirtualBox media registry. With VirtualBox 4.0 this is no longer necessary; media are added to media registries automatically. The “closemedium” call has been retained, however, to allow for explicitly removing a medium from a registry.

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--device The number of the port’s device which is to be modiﬁed. Mandatory, unless the

storage controller has only a single device per port.
--type Deﬁne the type of the drive to which the medium is being attached/detached/modiﬁed.

This argument can only be omitted if the type of medium can be determined from either the medium given with the --medium argument or from a previous medium attachment.
--medium Speciﬁes what is to be attached. The following values are supported:

• “none”: Any existing device should be removed from the given slot.
• “emptydrive”: For a virtual DVD or ﬂoppy drive only, this makes the device slot behaves like a removeable drive into which no media has been inserted.
• “additions”: For a virtual DVD drive only, this attaches the VirtualBox Guest Additions image to the given device slot.
• If a UUID is speciﬁed, it must be the UUID of a storage medium that is already known to VirtualBox (e.g. because it has been attached to another virtual machine). See chapter 8.4, VBoxManage list, page 126 for how to list known media. This medium is then attached to the given device slot.
• If a ﬁlename is speciﬁed, it must be the full path of an existing disk image (ISO, RAW,
VDI, VMDK or other), which is then attached to the given device slot.
• “host:<drive>“: For a virtual DVD or ﬂoppy drive only, this connects the given device slot to the speciﬁed DVD or ﬂoppy drive on the host computer.
• “iscsi”: For virtual hard disks only, this allows for specifying an iSCSI target. In this case, more parameters must be given; see below.
Some of the above changes, in particular for removeable media (ﬂoppies and CDs/DVDs), can be effected while a VM is running. Others (device changes or changes in hard disk device slots) require the VM to be powered off.
--mtype Deﬁnes how this medium behaves with respect to snapshots and write operations. See

chapter 5.4, Special image write modes, page 86 for details.
--comment Any description that you want to have stored with this medium (optional; for exam-

ple, for an iSCSI target, “Big storage server downstairs”). This is purely descriptive and not needed for the medium to function correctly.
--setuuid, --setparentuuid Modiﬁes the UUID or parent UUID of a medium before attach-

ing it to a VM. This is an expert option. Inappropriate use can make the medium unusable or lead to broken VM conﬁgurations if any other VM is referring to the same media already.
The most frequently used variant is --setuuid "", which assigns a new (random) UUID to an image. This is useful to resolve the duplicate UUID errors if one duplicated an image using ﬁle copy utilities.
--passthrough For a virtual DVD drive only, you can enable DVD writing support (currently

experimental; see chapter 5.9, CD/DVD support, page 92).
--tempeject For a virtual DVD drive only, you can conﬁgure the behavior for guest-triggered

medium eject. If this is set to “on”, the eject has only temporary effects. If the VM is powered off and restarted the originally conﬁgured medium will be still in the drive.
--nonrotational This switch allows to enable the non-rotational ﬂag for virtual hard disks.

Some guests (i.e. Windows 7+) treat such disks like SSDs and don’t perform disk fragmentation on such media.
--bandwidthgroup Sets the bandwidth group to use for the given device; see chapter 5.8, Lim-

iting bandwidth for disk images, page 91.

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--forceunmount For a virtual DVD or ﬂoppy drive only, this forcibly unmounts the

DVD/CD/Floppy or mounts a new DVD/CD/Floppy even if the previous one is locked down by the guest for reading. Again, see chapter 5.9, CD/DVD support, page 92 for details. When “iscsi” is used with the --medium parameter for iSCSI support – see chapter 5.10, iSCSI servers, page 92 –, additional parameters must or can be used:
--server The host name or IP address of the iSCSI target; required.
--target Target name string. This is determined by the iSCSI target and used to identify the

storage resource; required.
--tport TCP/IP port number of the iSCSI service on the target (optional).
--lun Logical Unit Number of the target resource (optional). Often, this value is zero.
--username, --password Username and password (initiator secret) for target authentication,

if required (optional).
Note: Username and password are stored without encryption (i.e. in clear text) in the
XML machine conﬁguration ﬁle if no settings password is provided. When a settings password was speciﬁed the ﬁrst time, the password is stored encrypted.

--intnet If speciﬁed, connect to the iSCSI target via Internal Networking. This needs further

conﬁguration which is described in chapter 9.9.3, Access iSCSI targets via Internal Networking, page 186.

8.19 VBoxManage storagectl
This command attaches/modiﬁes/removes a storage controller. After this, virtual media can be attached to the controller with the storageattach command (see the next section).
The syntax is as follows:
VBoxManage storagectl

<uuid|vmname>
--name <name>
[--add <ide/sata/scsi/floppy>]
[--controller <LsiLogic|LSILogicSAS|BusLogic|
IntelAhci|PIIX3|PIIX4|ICH6|I82078|usb>]
[--sataportcount <1-30>]
[--hostiocache on|off]
[--bootable on|off]
[--remove]

where the parameters mean: uuid|vmname The VM UUID or VM Name. Mandatory.
--name Name of the storage controller. Mandatory.
--add Deﬁne the type of the system bus to which the storage controller must be connected.
--controller Allows to choose the type of chipset being emulated for the given storage con-

troller.
--sataportcount This determines how many ports the SATA controller should support.

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--hostiocache Conﬁgures the use of the host I/O cache for all disk images attached to this

storage controller. For details, please see chapter 5.7, Host I/O caching, page 90.
--bootable Selects whether this controller is bootable.
--remove Removes the storage controller from the VM conﬁg.

8.20 VBoxManage bandwidthctl
This command creates/deletes/modiﬁes/shows bandwidth groups of the given virtual machine:
VBoxManage bandwidthctl

<uuid|vmname> add <name> --type disk|network --limit <megabytes per second>[k|m|g|K|M|G] | set <name> --limit <megabytes per second>[k|m|g|K|M|G] | remove <name> | list [--machinereadable]

The following subcommands are available:
• add, creates a new bandwidth group of given type.
• set, modiﬁes the limit for an existing bandwidth group.
• remove, destroys a bandwidth group.
• list, shows all bandwidth groups deﬁned for the given VM.
The parameters mean: uuid|vmname The VM UUID or VM Name. Mandatory.
--name Name of the bandwidth group. Mandatory.
--type Type of the bandwidth group. Mandatory. Two types are supported: disk and network.

See chapter 5.8, Limiting bandwidth for disk images, page 91 or chapter 6.10, Limiting bandwidth for network I/O, page 103 for a description of a particular type.
--limit Speciﬁes the limit for the given group. Can be changed while the VM is running. The

default unit is megabytes per second. The unit can be changed by specifying one of the following sufﬁxes: k for kilobits/s, m for megabits/s, g for gigabits/s, K for kilobytes/s, M for megabytes/s, G for gigabytes/s.

Note: The network bandwidth limits apply only to the trafﬁc being sent by virtual machines. The trafﬁc being received by VMs is unlimited.

Note: To remove a bandwidth group it must not be referenced by any disks or adapters in running VM.

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8.21 VBoxManage showhdinfo
This command shows information about a virtual hard disk image, notably its size, its size on disk, its type and the virtual machines which use it.
Note: For compatibility with earlier versions of VirtualBox, the “showvdiinfo” command is also supported and mapped internally to the “showhdinfo” command.
The disk image must be speciﬁed either by its UUID (if the medium is registered) or by its ﬁlename. Registered images can be listed by VBoxManage list hdds (see chapter 8.4, VBoxManage list, page 126 for more information). A ﬁlename must be speciﬁed as valid path, either as an absolute path or as a relative path starting from the current directory.

8.22 VBoxManage createhd
This command creates a new virtual hard disk image. The syntax is as follows:
VBoxManage createhd

--filename <filename>
--size <megabytes>
[--format VDI|VMDK|VHD] (default: VDI)
[--variant Standard,Fixed,Split2G,Stream,ESX]

where the parameters mean:
--filename Allows to choose a ﬁle name. Mandatory.
--size Allows to deﬁne the image capacity, in 1 MiB units. Mandatory.
--format Allows to choose a ﬁle format for the output ﬁle different from the ﬁle format of the

input ﬁle.
--variant Allows to choose a ﬁle format variant for the output ﬁle. It is a comma-separated list

of variant ﬂags. Not all combinations are supported, and specifying inconsistent ﬂags will result in an error message.

Note: For compatibility with earlier versions of VirtualBox, the “createvdi” command is also supported and mapped internally to the “createhd” command.

8.23 VBoxManage modifyhd
With the modifyhd command, you can change the characteristics of a disk image after it has been created:
VBoxManage modifyhd

<uuid|filename>
[--type normal|writethrough|immutable|shareable| readonly|multiattach] [--autoreset on|off]
[--compact]
[--resize <megabytes>|--resizebyte <bytes>]

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Note: Despite the “hd” in the subcommand name, the command works with all disk images, not only hard disks. For compatibility with earlier versions of VirtualBox, the
“modifyvdi” command is also supported and mapped internally to the “modifyhd” command.
The disk image to modify must be speciﬁed either by its UUID (if the medium is registered) or by its ﬁlename. Registered images can be listed by VBoxManage list hdds (see chapter 8.4,
VBoxManage list, page 126 for more information). A ﬁlename must be speciﬁed as valid path, either as an absolute path or as a relative path starting from the current directory.
The following options are available:
• With the --type argument, you can change the type of an existing image between the normal, immutable, write-through and other modes; see chapter 5.4, Special image write modes, page 86 for details.
• For immutable (differencing) hard disks only, the --autoreset on|off option determines whether the disk is automatically reset on every VM startup (again, see chapter 5.4, Special image write modes, page 86). The default is “on”.
• With the --compact option, can be used to compact disk images, i.e. remove blocks that only contains zeroes. This will shrink a dynamically allocated image again; it will reduce the physical size of the image without affecting the logical size of the virtual disk. Compaction works both for base images and for diff images created as part of a snapshot.
For this operation to be effective, it is required that free space in the guest system ﬁrst be zeroed out using a suitable software tool. For Windows guests, you can use the sdelete tool provided by Microsoft. Execute sdelete -z in the guest to zero the free disk space before compressing the virtual disk image. For Linux, use the zerofree utility which supports ext2/ext3 ﬁlesystems. For Mac OS X guests, use the Erase Free Space feature of the built-in Disk Utility. Use Zero Out Data there.
Please note that compacting is currently only available for VDI images. A similar effect can be achieved by zeroing out free blocks and then cloning the disk to any other dynamically allocated format. You can use this workaround until compacting is also supported for disk formats other than VDI.
• The --resize x option (where x is the desired new total space in megabytes) allows you to change the capacity of an existing image; this adjusts the logical size of a virtual disk without affecting the physical size much.3 This currently works only for VDI and
VHD formats, and only for the dynamically allocated variants, and can only be used to expand (not shrink) the capacity. For example, if you originally created a 10G disk which is now full, you can use the --resize 15360 command to change the capacity to 15G
(15,360MB) without having to create a new image and copy all data from within a virtual machine. Note however that this only changes the drive capacity; you will typically next need to use a partition management tool inside the guest to adjust the main partition to ﬁll the drive.
The --resizebyte x option does almost the same thing, except that x is expressed in bytes instead of megabytes.

8.24 VBoxManage clonehd
This command duplicates a registered virtual hard disk image to a new image ﬁle with a new unique identiﬁer (UUID). The new image can be transferred to another host system or imported
3 Image

resizing was added with VirtualBox 4.0.

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8 VBoxManage into VirtualBox again using the Virtual Media Manager; see chapter 5.3, The Virtual Media Manager, page 85 and chapter 5.6, Cloning disk images, page 90. The syntax is as follows:
VBoxManage clonehd

<uuid|inutfile> <uuid|outputfile>
[--format VDI|VMDK|VHD|RAW|<other>]
[--variant Standard,Fixed,Split2G,Stream,ESX]
[--existing]

The disk image to clone as well as the target image must be described either by its UUIDs (if the mediums are registered) or by its ﬁlename. Registered images can be listed by VBoxManage list hdds (see chapter 8.4, VBoxManage list, page 126 for more information). A ﬁlename must be speciﬁed as valid path, either as an absolute path or as a relative path starting from the current directory. The following options are available:
--format Allow to choose a ﬁle format for the output ﬁle different from the ﬁle format of the

input ﬁle.
--variant Allow to choose a ﬁle format variant for the output ﬁle. It is a comma-separated list

of variant ﬂags. Not all combinations are supported, and specifying inconsistent ﬂags will result in an error message.
--existing Perform the clone operation to an already existing destination medium. Only the

portion of the source medium which ﬁts into the destination medium is copied. This means if the destination medium is smaller than the source only a part of it is copied, and if the destination medium is larger than the source the remaining part of the destination medium is unchanged.

Note: For compatibility with earlier versions of VirtualBox, the “clonevdi” command is also supported and mapped internally to the “clonehd” command.

8.25 VBoxManage convertfromraw
This command converts a raw disk image to a VirtualBox Disk Image (VDI) ﬁle. The syntax is as follows: VBoxManage convertfromraw

VBoxManage convertfromraw

<filename> <outputfile>
[--format VDI|VMDK|VHD]
[--variant Standard,Fixed,Split2G,Stream,ESX]
[--uuid <uuid>] stdin <outputfile> <bytes>
[--format VDI|VMDK|VHD]
[--variant Standard,Fixed,Split2G,Stream,ESX]
[--uuid <uuid>]

where the parameters mean:
--bytes The size of the image ﬁle, in bytes, provided through stdin.
--format Select the disk image format to create. Default is VDI.
--variant Allow to choose a ﬁle format variant for the output ﬁle. It is a comma-separated list

of variant ﬂags. Not all combinations are supported, and specifying inconsistent ﬂags will result in an error message.
--uuid Allow to speciﬁy the UUID of the output ﬁle.

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The second form forces VBoxManage to read the content for the disk image from standard input
(useful for using that command in a pipe).
Note: For compatibility with earlier versions of VirtualBox, the “convertdd” command is also supported and mapped internally to the “convertfromraw” command.

8.26 VBoxManage getextradata/setextradata
These commands let you attach and retrieve string data to a virtual machine or to a VirtualBox conﬁguration (by specifying global instead of a virtual machine name). You must specify a key
(as a text string) to associate the data with, which you can later use to retrieve it. For example:
VBoxManage setextradata Fedora5 installdate 2006.01.01
VBoxManage setextradata SUSE10 installdate 2006.02.02

would associate the string “2006.01.01” with the key installdate for the virtual machine Fedora5, and “2006.02.02” on the machine SUSE10. You could retrieve the information as follows:
VBoxManage getextradata Fedora5 installdate

which would return
VirtualBox Command Line Management Interface Version 5.0.0
(C) 2005-2015 Oracle Corporation
All rights reserved.
Value: 2006.01.01

To remove a key, the setextradata command must be run without specifying data (only the key), for example:
VBoxManage setextradata Fedora5 installdate

8.27 VBoxManage setproperty
This command is used to change global settings which affect the entire VirtualBox installation.
Some of these correspond to the settings in the “Global settings” dialog in the graphical user interface. The following properties are available: machinefolder This speciﬁes the default folder in which virtual machine deﬁnitions are kept;

see chapter 10.1, Where VirtualBox stores its ﬁles, page 215 for details. hwvirtexclusive This speciﬁes whether VirtualBox will make exclusive use of the hardware

virtualization extensions (Intel VT-x or AMD-V) of the host system’s processor; see chapter
10.3, Hardware vs. software virtualization, page 219. If you wish to share these extensions with other hypervisors running at the same time, you must disable this setting. Doing so has negative performance implications. vrdeauthlibrary This speciﬁes which library to use when “external” authentication has been

selected for a particular virtual machine; see chapter 7.1.5, RDP authentication, page 109 for details. websrvauthlibrary This speciﬁes which library the web service uses to authenticate users.

For details about the VirtualBox web service, please refer to the separate VirtualBox SDK reference (see chapter 11, VirtualBox programming interfaces, page 225).

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8 VBoxManage vrdeextpack This speciﬁes which library implements the VirtualBox Remote Desktop Extension. loghistorycount This selects how many rotated (old) VM logs are kept. autostartdbpath This selects the path to the autostart database. See chapter 9.24, Starting

virtual machines during system boot, page 209. defaultfrontend This selects the global default VM frontend setting. See chapter 8.12, VBox-

Manage startvm, page 140. logginglevel This conﬁgures the VBoxSVC release logging details.4

8.28 VBoxManage usbﬁlter add/modify/remove
The usbfilter commands are used for working with USB ﬁlters in virtual machines, or global ﬁlters which affect the whole VirtualBox setup. Global ﬁlters are applied before machine-speciﬁc ﬁlters, and may be used to prevent devices from being captured by any virtual machine. Global ﬁlters are always applied in a particular order, and only the ﬁrst ﬁlter which ﬁts a device is applied. So for example, if the ﬁrst global ﬁlter says to hold (make available) a particular Kingston memory stick device and the second to ignore all Kingston devices, that memory stick will be available to any machine with an appropriate ﬁlter, but no other Kingston device will.
When creating a USB ﬁlter using usbfilter add, you must supply three or four mandatory parameters. The index speciﬁes the position in the list at which the ﬁlter should be placed. If there is already a ﬁlter at that position, then it and the following ones will be shifted back one place. Otherwise the new ﬁlter will be added onto the end of the list. The target parameter selects the virtual machine that the ﬁlter should be attached to or use “global” to apply it to all virtual machines. name is a name for the new ﬁlter and for global ﬁlters, action says whether to allow machines access to devices that ﬁt the ﬁlter description (“hold”) or not to give them access
(“ignore”). In addition, you should specify parameters to ﬁlter by. You can ﬁnd the parameters for devices attached to your system using VBoxManage list usbhost. Finally, you can specify whether the ﬁlter should be active, and for local ﬁlters, whether they are for local devices, remote
(over an RDP connection) or either.
When you modify a USB ﬁlter using usbfilter modify, you must specify the ﬁlter by index (see the output of VBoxManage list usbfilters to ﬁnd global ﬁlter indexes and that of
VBoxManage showvminfo to ﬁnd indexes for individual machines) and by target, which is either a virtual machine or “global”. The properties which can be changed are the same as for usbfilter add. To remove a ﬁlter, use usbfilter remove and specify the index and the target.

8.29 VBoxManage sharedfolder add/remove
This command allows you to share folders on the host computer with guest operating systems.
For this, the guest systems must have a version of the VirtualBox Guest Additions installed which supports this functionality.
Shared folders are described in detail in chapter 4.3, Shared folders, page 69.

8.30 VBoxManage guestproperty
The “guestproperty” commands allow you to get or set properties of a running virtual machine.
Please see chapter 4.7, Guest properties, page 76 for an introduction. As explained there, guest properties are arbitrary key/value string pairs which can be written to and read from by either
4 http://www.virtualbox.org/wiki/VBoxLogging.

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8 VBoxManage the guest or the host, so they can be used as a low-volume communication channel for strings, provided that a guest is running and has the Guest Additions installed. In addition, a number of values whose keys begin with “/VirtualBox/“ are automatically set and maintained by the Guest
Additions.
The following subcommands are available (where <vm>, in each case, can either be a VM name or a VM UUID, as with the other VBoxManage commands):
• enumerate <vm> [--patterns <pattern>]: This lists all the guest properties that are available for the given VM, including the value. This list will be very limited if the guest’s service process cannot be contacted, e.g. because the VM is not running or the Guest
Additions are not installed.
If --patterns <pattern> is speciﬁed, it acts as a ﬁlter to only list properties that match the given pattern. The pattern can contain the following wildcard characters:
– * (asterisk): represents any number of characters; for example, “/VirtualBox*“ would match all properties beginning with “/VirtualBox”.
– ? (question mark): represents a single arbitrary character; for example, “fo?“ would match both “foo” and “for”.
– | (pipe symbol): can be used to specify multiple alternative patterns; for example,
“s*|t*“ would match anything starting with either “s” or “t”.
• get <vm> <property> : This retrieves the value of a single property only. If the property cannot be found (e.g. because the guest is not running), this will print
No value set!

• set <vm> <property> [<value> [--flags <flags>]]: This allows you to set a guest property by specifying the key and value. If <value> is omitted, the property is deleted.
With --flags you can optionally specify additional behavior (you can combine several by separating them with commas):
– TRANSIENT: the value will not be stored with the VM data when the VM exits;
– TRANSRESET: the value will be deleted as soon as the VM restarts and/or exits;
– RDONLYGUEST: the value can only be changed by the host, but the guest can only read it; – RDONLYHOST: reversely, the value can only be changed by the guest, but the host can only read it;
– READONLY: a combination of the two, the value cannot be changed at all.
• wait <vm> <pattern> --timeout <timeout>: This waits for a particular value described by “pattern” to change or to be deleted or created. The pattern rules are the same as for the “enumerate” subcommand above.
• delete <vm> <property> : Deletes a formerly set guest property.

8.31 VBoxManage guestcontrol
The guestcontrol commands allow you to control certain things inside a guest from the host.
Please see chapter 4.8, Guest control, page 78 for an introduction.
There are two sets of subcommands here. The ﬁrst set requires guest credentials to be speciﬁed, the second set does not.
The ﬁrst set of subcommands are on the following form:

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VBoxManage guestcontrol <uuid|vmname> <sub-command>
[-v|--verbose] [-q|quiet] [--username <name>] [--domain <domain> ]
[--passwordfile <file> | --password <password>] ...

and the second set are on the following form:
VBoxManage guestcontrol <uuid|vmname> <sub-command>
[-v|--verbose] [-q|quiet] ...

where the common parameters are: uuid|vmname The VM UUID or VM name. Mandatory.
--username <name> Name of the user the process should run under. This user must exist on

the guest OS. If not speciﬁed the host user name is used.
--domain <domain> User domain for windows guests, optional.
--passwordfile <file> Password of the speciﬁed user account to be read from the given ﬁle.

If not given, an empty password is assumed.
--password <password> Password of the speciﬁed user account. If not given, an empty pass-

word is assumed.
-v|--verbose Makes the sub-command execution more noisy.
-q|--quiet Makes the sub-command execution more quiet.

The ﬁrst set of subcommands:
• run, allows you to execute a guest program waiting for it to complete and forwarding stdout, stderr and stdin to/from the host.
VBoxManage guestcontrol <uuid|vmname> run [common-options]
[--exe <path to executable>] [--timeout <msec>]
[-E|--putenv <NAME>[=<VALUE>]] [--unquoted-args]
[--ignore-operhaned-processes] [--no-profile]
[--no-wait-stdout|--wait-stdout]
[--no-wait-stderr|--wait-stderr]
[--dos2unix] [--unix2dos]
-- <program/arg0> [argument1] ... [argumentN]]

where the options are:
--exe "<path to program>" Guest path to the guest executable that should be executed. in the guest, e.g. C:\Windows\System32\calc.exe
--username <name> Name of the user the process should run under. This user must exist

on the guest OS.
--passwordfile <file> Password of the user account speciﬁed to be read from the given

ﬁle. If not given, an empty password is assumed.
--password <password> Password of the user account speciﬁed with --username. If not

given, an empty password is assumed.
--dos2unix Converts output from DOS/Windows guests to UNIX-compatible line endings

(CR + LF -> LF). Not implemented yet.

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--environment "<NAME>=<VALUE>" One or more environment variables to be set or un-

set.
By default, the new process in the guest will be created with the standard environment of the guest OS. This option allows for modifying that environment. To set/modify a variable, a pair of NAME=VALUE must be speciﬁed; to unset a certain variable, the name with no value must set, e.g. NAME=.
Arguments containing spaces must be enclosed in quotation marks. More than one
--environment at a time can be speciﬁed to keep the command line tidy.
--timeout <msec> Value (in milliseconds) that speciﬁes the time how long the started

process is allowed to run and how long VBoxManage waits for getting output from that process. If no timeout is speciﬁed, VBoxManage will wait forever until the started process ends or an error occured.
--unix2dos Converts output from a UNIX/Linux guests to DOS-/Windows-compatible

line endings (LF -> CR + LF). Not implemented yet.
--verbose Tells VBoxManage to be more verbose.
--wait-exit Waits until the process ends and outputs its exit code along with the exit

reason/ﬂags.
--wait-stdout Waits until the process ends and outputs its exit code along with the exit

reason/ﬂags. While waiting VBoxManage retrieves the process output collected from stdout. --wait-stderr Waits until the process ends and outputs its exit code along with the exit

reason/ﬂags. While waiting VBoxManage retrieves the process output collected from stderr. [-- [<argument1s>] ...

[<argumentNs>]] One or more arguments to pass to the

process being executed.
Arguments containing spaces must be enclosed in quotation marks.

Note: On Windows there are certain limitations for graphical applications; please see chapter 14, Known limitations, page 247 for more information.
Examples:
VBoxManage --nologo guestcontrol "My VM" execute --image "/bin/ls"
--username foo --passwordfile bar.txt --wait-exit --wait-stdout -- -l /usr
VBoxManage --nologo guestcontrol "My VM" execute --image "c:\\windows\\system32\\ipconfig.exe"
--username foo --passwordfile bar.txt --wait-exit --wait-stdout

Note that the double backslashes in the second example are only required on Unix hosts.
Note: For certain commands a user name of an existing user account on the guest must be speciﬁed; anonymous executions are not supported for security reasons. A user account password, however, is optional and depends on the guest’s OS security policy or rules. If no password is speciﬁed for a given user name, an empty password will be used. On certain OSes like Windows the security policy may needs to be adjusted in order to allow user accounts with an empty password set. Also, global domain rules might apply and therefore cannot be changed.
Starting at VirtualBox 4.1.2 guest process execution by default is limited to serve up to 5 guest processes at a time. If a new guest process gets started which would exceed this limit,

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8 VBoxManage the oldest not running guest process will be discarded in order to be able to run that new process. Also, retrieving output from this old guest process will not be possible anymore then. If all 5 guest processes are still active and running, starting a new guest process will result in an appropriate error message.
To raise or lower the guest process execution limit, either the guest property
/VirtualBox/GuestAdd/VBoxService/--control-procs-max-kept or VBoxService’ command line by specifying --control-procs-max-kept needs to be modiﬁed. A restart of the guest OS is required afterwards. To serve unlimited guest processes, a value of 0 needs to be set (not recommended).
• copyto, which allows copying ﬁles from the host to the guest (only with installed Guest
Additions 4.0 and later).
VBoxManage guestcontrol <uuid|vmname> copyto|cp
<guest source> <host dest> --username <name>
[--passwordfile <file> | --password <password>]
[--dryrun] [--follow] [--recursive] [--verbose]

where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory. source on host Absolute path of source ﬁle(s) on host to copy over to the guest, e.g.
C:\Windows\System32\calc.exe. This also can be a wildcard expression, e.g.
C:\Windows\System32\*.dll
destination on guest Absolute destination path on the guest, e.g. C:\Temp
--username <name> Name of the user the copy process should run under. This user must

exist on the guest OS.
--passwordfile <file> Password of the user account speciﬁed to be read from the given

ﬁle. If not given, an empty password is assumed.
--password <password> Password of the user account speciﬁed with --username. If not

given, an empty password is assumed.
--dryrun Tells VBoxManage to only perform a dry run instead of really copying ﬁles to

the guest.
--follow Enables following symlinks on the host’s source.
--recursive Recursively copies ﬁles/directories of the speciﬁed source.
--verbose Tells VBoxManage to be more verbose.
--flags <flags> Additional ﬂags to set. This is not used at the moment.

• copyfrom, which allows copying ﬁles from the guest to the host (only with installed Guest
Additions 4.0 and later). It has the same parameters as copyto above.
• createdirectory, which allows copying ﬁles from the host to the guest (only with installed Guest Additions 4.0 and later).
VBoxManage guestcontrol <uuid|vmname> createdir[ectory]|mkdir|md
<guest directory>... --username <name>
[--passwordfile <file> | --password <password>]
[--parents] [--mode <mode>] [--verbose]

where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory. directory to create on guest Absolute path of directory/directories to create on guest, e.g. D:\Foo\Bar. Parent directories need to exist (e.g. in this example D:\Foo) when switch --parents is omitted. The speciﬁed user must have appropriate rights

to create the speciﬁed directory.

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--username <name> Name of the user the copy process should run under. This user must

exist on the guest OS.
--passwordfile <file> Password of the user account speciﬁed to be read from the given

ﬁle. If not given, an empty password is assumed.
--password <password> Password of the user account speciﬁed with --username. If not

given, an empty password is assumed.
--parents Also creates not yet existing parent directories of the speciﬁed directory, e.g. if the directory D:\Foo of D:\Foo\Bar does not exist yet it will be created. Without specifying --parent the action would have failed.
--mode <mode> Sets the permission mode of the speciﬁed directory. Only octal modes
(e.g. 0755) are supported right now.
--verbose Tells VBoxManage to be more verbose.

• removedirectory, which allows deletion of guest directories (only with installed Guest
Additions 4.3.2 and later).
VBoxManage guestcontrol <uuid|vmname> removedir[ectory]|rmdir
<guest directory>... --username <name>
[--passwordfile <file> | --password <password>]
[--recursive|-R|-r] [--verbose]

where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory. directory to remove on guest Absolute path of directory/directories to remove on guest, e.g. D:\Foo\Bar. The speciﬁed user must have appropriate rights to delete

the speciﬁed guest directories.
--username <name> Name of the user the copy process should run under. This user must

exist on the guest OS.
--passwordfile <file> Password of the user account speciﬁed to be read from the given

ﬁle. If not given, an empty password is assumed.
--password <password> Password of the user account speciﬁed with --username. If not

given, an empty password is assumed.
--recursive Remove directories and their contents recursively.
--verbose Tells VBoxManage to be more verbose.

• removefile, which allows deletion of guest ﬁles (only with installed Guest Additions 4.3.2 and later).
VBoxManage guestcontrol <uuid|vmname> removefile|rm
<guest file>... --username <name>
[--passwordfile <file> | --password <password>]
[--verbose]

where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory. file to remove on guest Absolute path of a ﬁle/ﬁles to remove on guest, e.g.
D:\Foo\Bar\text.txt. The speciﬁed user must have appropriate rights to delete the

speciﬁed guest ﬁles.
--username <name> Name of the user the copy process should run under. This user must

exist on the guest OS.
--passwordfile <file> Password of the user account speciﬁed to be read from the given

ﬁle. If not given, an empty password is assumed.

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--password <password> Password of the user account speciﬁed with --username. If not

given, an empty password is assumed.
--verbose Tells VBoxManage to be more verbose.

• ren[ame]|mv, which allows renaming of guest ﬁles and/or directories (only with installed
Guest Additions 4.3.2 and later).
VBoxManage guestcontrol <uuid|vmname> ren[ame]|mv
<source>... <dest> --username <name>
[--passwordfile <file> | --password <password>]
[--verbose]

where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory. source Absolute path of one or more source(s) to move to destination. If more than

one source is speciﬁed, destination must be an existing directory on the guest. The speciﬁed user must have appropriate rights to access source and destination ﬁles and directories. dest Absolute path of the destination to move the source(s) to. This can be a directory or

a ﬁle, depending if one or more sources have been speciﬁed. The speciﬁed user must have appropriate rights to access the destination ﬁle and directory.
--username <name> Name of the user the copy process should run under. This user must

exist on the guest OS.
--passwordfile <file> Password of the user account speciﬁed to be read from the given

ﬁle. If not given, an empty password is assumed.
--password <password> Password of the user account speciﬁed with --username. If not

given, an empty password is assumed.
--verbose Tells VBoxManage to be more verbose.

• createtemporary, which allows copying ﬁles from the host to the guest (only with installed Guest Additions 4.2 and later).
VBoxManage guestcontrol <uuid|vmname> createtemp[orary]|mktemp
<template> --username <name>
[--passwordfile <file> | --password <password>]
[--directory] [--secure] [--tmpdir <directory>]
[--domain <domain>] [--mode <mode>] [--verbose]

where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory. template A ﬁle name without a path and with at least three consecutive ’X’ characters or

ending in ’X’
--username <name> Name of the user the copy process should run under. This user must

exist on the guest OS.
--passwordfile <file> Password of the user account speciﬁed to be read from the given

ﬁle. If not given, an empty password is assumed.
--password <password> Password of the user account speciﬁed with --username. If not

given, an empty password is assumed.
--directory Create a temporary directory instead of a ﬁle.
--secure Secure creation. The ﬁle mode is ﬁxed to 0755. And the operation will fail if it

cannot performed securely.
--tmpdir <directory> Directory where the ﬁle / directory is created. If not speciﬁed,

the platform-speciﬁc temp directory is used.

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--mode <mode> Sets the permission mode of the speciﬁed directory. Only octal modes
(e.g. 0755) are supported right now.
--verbose Tells VBoxManage to be more verbose.

• list, which lists various guest control information such as open guest sessions, guest processes and guest ﬁles.
VBoxManage guestcontrol <uuid|vmname> list
<all|sessions|processes|files> [--verbose]

where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory. all|sessions|processes|files Whether to list guest sessions, guest processes, guest

ﬁles or all information available. Mandatory.
--verbose Tells VBoxManage to be more verbose.

• process kill, which terminates speciﬁc guest processes of a guest session, based on either the session’s ID or the session’s name.
VBoxManage guestcontrol <uuid|vmname> process kill
--session-id <ID>
| --session-name <name or pattern>
[--verbose]
<PID> ... <PID n>

where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory.
--session-id Speciﬁes the guest session to use by its ID.
--session-name Speciﬁes the guest session to use by its name. Multiple sessions can be

closed when specifying * or ? wildcards.
--verbose Tells VBoxManage to be more verbose.
<PID> ...

<PID n> List of process identiﬁers (PIDs) to terminate.

• [p[s]]kill, which terminates speciﬁc guest processes of a guest session, based on either the session’s ID or the session’s name.
VBoxManage guestcontrol <uuid|vmname> process kill
--session-id <ID>
| --session-name <name or pattern>
[--verbose]
<PID> ... <PID n>

where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory.
--session-id Speciﬁes the guest session to use by its ID.
--session-name Speciﬁes the guest session to use by its name. Multiple sessions can be

closed when specifying * or ? wildcards.
--verbose Tells VBoxManage to be more verbose.
<PID> ...

<PID n> List of process identiﬁers (PIDs) to terminate.

• session close, which closes speciﬁc guest sessions, based on either the session’s ID or the session’s name.
VBoxManage guestcontrol <uuid|vmname> session close
--session-id <ID>
| --session-name <name or pattern>
| --all
[--verbose]

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8 VBoxManage where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory.
--session-id Close a guest session speciﬁed by its ID.
--session-name Close a guest session speciﬁed by its name. Multiple sessions can be

closed when specifying * or ? wildcards.
--all Close all guest sessions.
--verbose Tells VBoxManage to be more verbose.

• stat, which displays ﬁle or ﬁle system status on the guest.
VBoxManage guestcontrol <uuid|vmname> stat
<file>... --username <name>
[--passwordfile <file> | --password <password>]
[--verbose]

where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory. file element(s) to check on guest Absolute path of directory/directories to check on guest, e.g. /home/foo/a.out. The speciﬁed user must have appropriate rights to

access the given ﬁle element(s).
--username <name> Name of the user the copy process should run under. This user must

exist on the guest OS.
--passwordfile <file> Password of the user account speciﬁed to be read from the given

ﬁle. If not given, an empty password is assumed.
--password <password> Password of the user account speciﬁed with --username. If not

given, an empty password is assumed.
--verbose Tells VBoxManage to be more verbose.

• updateadditions, which allows for updating an already installed Guest Additions version on the guest (only already installed Guest Additions 4.0 and later).
VBoxManage guestcontrol <uuid|vmname> updateadditions
[--source "<guest additions .ISO file to use>"] [--verbose]
[--wait-start] [-- [<argument1>] ... [<argumentN>]]

where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory.
--source “<guest additions .ISO ﬁle to use>“ Full path to an alternative VirtualBox

Guest Additions .ISO ﬁle to use for the Guest Additions update.
--verbose Tells VBoxManage to be more verbose.
--wait-start Starts the regular updating process and waits until the actual Guest Ad-

ditions update inside the guest was started. This can be necessary due to needed interaction with the guest OS during the installation phase.
When omitting this ﬂag VBoxManage will wait for the whole Guest Additions update to complete.
[<argumentNs>]] Optional command line arguments to use for the Guest Additions installer. Useful for retroﬁtting features which weren’t installed before on the guest.

[-- [<argument1s>] ...

Arguments containing spaces must be enclosed in quotation marks.
• watch, which prints current guest control activity.

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VBoxManage guestcontrol <uuid|vmname> watch
[--verbose]

where the parameters mean: uuid|vmname The VM UUID or VM name. Mandatory.
--verbose Tells VBoxManage to be more verbose.

8.32 VBoxManage metrics
This command supports monitoring the usage of system resources. Resources are represented by various metrics associated with the host system or a particular VM. For example, the host system has a CPU/Load/User metric that shows the percentage of time CPUs spend executing in user mode over a speciﬁc sampling period.
Metric data is collected and retained internally; it may be retrieved at any time with the
VBoxManage metrics query subcommand. The data is available as long as the background
VBoxSVC process is alive. That process terminates shortly after all VMs and frontends have been closed. By default no metrics are collected at all. Metrics collection does not start until VBoxManage metrics setup is invoked with a proper sampling interval and the number of metrics to be retained. The interval is measured in seconds. For example, to enable collecting the host processor and memory usage metrics every second and keeping the 5 most current samples, the following command can be used:
VBoxManage metrics setup --period 1 --samples 5 host CPU/Load,RAM/Usage

Metric collection can only be enabled for started VMs. Collected data and collection settings for a particular VM will disappear as soon as it shuts down. Use VBoxManage metrics list subcommand to see which metrics are currently available. You can also use --list option with any subcommand that modiﬁes metric settings to ﬁnd out which metrics were affected.
Note that the VBoxManage metrics setup subcommand discards all samples that may have been previously collected for the speciﬁed set of objects and metrics.
To enable or disable metrics collection without discarding the data VBoxManage metrics enable and VBoxManage metrics disable subcommands can be used. Note that these subcommands expect metrics, not submetrics, like CPU/Load or RAM/Usage as parameters. In other words enabling CPU/Load/User while disabling CPU/Load/Kernel is not supported.
The host and VMs have different sets of associated metrics. Available metrics can be listed with VBoxManage metrics list subcommand.
A complete metric name may include an aggregate function. The name has the following form:
Category/Metric[/SubMetric][:aggregate]. For example, RAM/Usage/Free:min stands for the minimum amount of available memory over all retained data if applied to the host object.
Subcommands may apply to all objects and metrics or can be limited to one object or/and a list of metrics. If no objects or metrics are given in the parameters, the subcommands will apply to all available metrics of all objects. You may use an asterisk (“*“) to explicitly specify that the command should be applied to all objects or metrics. Use “host” as the object name to limit the scope of the command to host-related metrics. To limit the scope to a subset of metrics, use a metric list with names separated by commas.
For example, to query metric data on the CPU time spent in user and kernel modes by the virtual machine named “test”, you can use the following command:
VBoxManage metrics query test CPU/Load/User,CPU/Load/Kernel

The following list summarizes the available subcommands: list This subcommand shows the parameters of the currently existing metrics. Note that VM-

speciﬁc metrics are only available when a particular VM is running.

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8 VBoxManage setup This subcommand sets the interval between taking two samples of metric data and the

number of samples retained internally. The retained data is available for displaying with the query subcommand. The --list option shows which metrics have been modiﬁed as the result of the command execution. enable This subcommand “resumes” data collection after it has been stopped with disable

subcommand. Note that specifying submetrics as parameters will not enable underlying metrics. Use --list to ﬁnd out if the command did what was expected. disable This subcommand “suspends” data collection without affecting collection parameters

or collected data. Note that specifying submetrics as parameters will not disable underlying metrics. Use --list to ﬁnd out if the command did what was expected. query This subcommand retrieves and displays the currently retained metric data.

Note: The query subcommand does not remove or “ﬂush” retained data. If you query often enough you will see how old samples are gradually being “phased out” by new samples. collect This subcommand sets the interval between taking two samples of metric data and

the number of samples retained internally. The collected data is displayed periodically until Ctrl-C is pressed unless the --detach option is speciﬁed. With the --detach option, this subcommand operates the same way as setup does. The --list option shows which metrics match the speciﬁed ﬁlter.

8.33 VBoxManage hostonlyif
With “hostonlyif” you can change the IP conﬁguration of a host-only network interface. For a description of host-only networking, please refer to chapter 6.7, Host-only networking, page 101.
Each host-only interface is identiﬁed by a name and can either use the internal DHCP server or a manual IP conﬁguration (both IP4 and IP6).
The following list summarizes the available subcommands: ipconfig "<name>" Conﬁgure a hostonly interface create Ceates a new vboxnet<N> interface on the host OS. This command is essential before

you can attach VMs to host-only network. remove vboxnet<N> Removes a vboxnet<N> interface from the host OS.

8.34 VBoxManage dhcpserver
The “dhcpserver” commands allow you to control the DHCP server that is built into VirtualBox.
You may ﬁnd this useful when using internal or host-only networking. (Theoretically, you can enable it for a bridged network as well, but that will likely cause conﬂicts with other DHCP servers in your physical network.)
Use the following command line options:
• If you use internal networking for a virtual network adapter of a virtual machine, use
VBoxManage dhcpserver add --netname <network_name>, where <network_name> is the same network name you used with VBoxManage modifyvm <vmname> --intnet<X>
<network_name>.

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• If you use host-only networking for a virtual network adapter of a virtual machine, use VBoxManage dhcpserver add --ifname <hostonly_if_name> instead, where
<hostonly_if_name> is the same host-only interface name you used with VBoxManage modifyvm <vmname> --hostonlyadapter<X> <hostonly_if_name>.
Alternatively, you can also use the –netname option as with internal networks if you know the host-only network’s name; you can see the names with VBoxManage list hostonlyifs (see chapter 8.4, VBoxManage list, page 126 above).
The following additional parameters are required when ﬁrst adding a DHCP server:
• With --ip, specify the IP address of the DHCP server itself.
• With --netmask, specify the netmask of the network.
• With --lowerip and --upperip, you can specify the lowest and highest IP address, respectively, that the DHCP server will hand out to clients.
Finally, you must specify --enable or the DHCP server will be created in the disabled state, doing nothing.
After this, VirtualBox will automatically start the DHCP server for given internal or host-only network as soon as the ﬁrst virtual machine which uses that network is started.
Reversely, use VBoxManage dhcpserver remove with the given --netname <network_name> or --ifname <hostonly_if_name> to remove the DHCP server again for the given internal or host-only network.
To modify the settings of a DHCP server created earlier with VBoxManage dhcpserver add, you can use VBoxManage dhcpserver modify for a given network or host-only interface name.

8.35 VBoxManage debugvm
Introspection and guest debugging.

Synopsis
VBoxManage debugvm <uuid|vmname> dumpvmcore [--filename=name]
VBoxManage debugvm <uuid|vmname> info <item> [args...]
VBoxManage debugvm <uuid|vmname> injectnmi
VBoxManage debugvm <uuid|vmname> log [[--release] | [--debug]] [group-settings...]
VBoxManage debugvm <uuid|vmname> logdest [[--release] | [--debug]] [destinations...]
VBoxManage debugvm <uuid|vmname> logflags [[--release] | [--debug]] [flags...]
VBoxManage debugvm <uuid|vmname> osdetect
VBoxManage debugvm <uuid|vmname> osinfo
VBoxManage debugvm <uuid|vmname> osdmesg [--lines=lines]
VBoxManage debugvm <uuid|vmname> getregisters [--cpu=id] [reg-set.reg-name...]
VBoxManage debugvm <uuid|vmname> setregisters [--cpu=id] [reg-set.reg-name=value...]
VBoxManage debugvm <uuid|vmname> show [[--human-readable] | [--sh-export] |
[--sh-eval] | [--cmd-set]] [settings-item...]
VBoxManage debugvm <uuid|vmname> statistics [--reset] [--descriptions] [--pattern=pattern]

Description
The “debugvm” commands are for experts who want to tinker with the exact details of virtual machine execution. Like the VM debugger described in chapter 12.1.3, The built-in VM debugger, page 227, these commands are only useful if you are very familiar with the details of the PC architecture and how to debug software.

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Common options
The subcommands of debugvm all operate on a running virtual machine: uuid|vmname Either the UUID or the name (case sensitive) of a VM. debugvm dumpvmcore
VBoxManage debugvm <uuid|vmname> dumpvmcore [--filename=name]

Creates a system dump ﬁle of the speciﬁed VM. This ﬁle will have the standard ELF core format
(with custom sections); see chapter 12.1.4, VM core format, page 229.
This corresponds to the writecore command in the debugger.
--filename=filename

The name of the output ﬁle. debugvm info
VBoxManage debugvm <uuid|vmname> info <item> [args...]

Displays info items relating to the VMM, device emulations and associated drivers.
This corresponds to the info command in the debugger. info Name of the info item to display. The special name help will list all the available info items and hints about optional arguments. args Optional argument string for the info item handler. Most info items does not take any extra arguments. Arguments not recognized are generally ignored. debugvm injectnmi
VBoxManage debugvm <uuid|vmname> injectnmi

Causes a non-maskable interrupt (NMI) to be injected into the guest. This might be useful for certain debugging scenarios. What happens exactly is dependent on the guest operating system, but an NMI can crash the whole guest operating system. Do not use unless you know what you’re doing. debugvm log
VBoxManage debugvm <uuid|vmname> log [[--release] | [--debug]] [group-settings...]

Changes the group settings for either debug (--debug) or release (--release) logger of the
VM process.
The group-settings are typically strings on the form em.e.f.l, hm=~0 and -em.f. Basic wildcards are supported for group matching. The all group is an alias for all the groups.
Please do keep in mind that the group settings are applied as modiﬁcations to the current ones.
This corresponds to the log command in the debugger.

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VBoxManage debugvm <uuid|vmname> logdest [[--release] | [--debug]] [destinations...]

Changes the destination settings for either debug (--debug) or release (--release) logger of the VM process.
For details on the destination format, the best source is src/VBox/Runtime/common/log/log.cpp. The destinations is one or more mnemonics, optionally preﬁxed by “no” to disable them.
Some of them take values after a “:“ or “=“ separator. Multiple mnemonics can be separated by space or given as separate arguments on the command line.
List of available destination: file[=file], nofile

Speciﬁes a log ﬁle. It no ﬁlname is given, one will be generated based on the current UTC time and VM process name and placed in the current directory of the VM process. Note that this will currently not have any effect if the log ﬁle has already been opened. dir=directory, nodir

Speciﬁes the output directory for log ﬁles. Note that this will currently not have any effect if the log ﬁle has already been opened. history=count, nohistory

A non-zero value enables log historization, with the value specifying how many old log ﬁles to keep. histsize=bytes The max size of a log ﬁle before it is historized. Default is inﬁnite. histtime=seconds The max age (in seconds) of a log ﬁle before it is historized. Default is inﬁnite. ringbuffer, noringbuffer

Only log to the log buffer until an explicit ﬂush (e.g. via an assertion) occurs. This is fast and saves diskspace. stdout, nostdout

Write the log content to standard output. stdout, nostdout

Write the log content to standard error. debugger, nodebugger

Write the log content to the debugger, if supported by the host OS. com, nocom

Writes logging to the COM port. This is only applicable for raw-mode and ring-0 logging. user, nouser

Custom destination which has no meaning to VM processes..
This corresponds to the logdest command in the debugger. debugvm logﬂags
VBoxManage debugvm <uuid|vmname> logflags [[--release] | [--debug]] [flags...]

Changes the ﬂags on either debug (--debug) or release (--release) logger of the VM process.
Please note that the modiﬁcations are applied onto the existing changes, they are not replacing them. 165

8 VBoxManage
The flags are a list of ﬂag mnemonics, optionally preﬁxed by a “no”, “¡‘, “~“ or “-“ to negate their meaning. The “+“ preﬁx can be used to undo previous negation or use as a separator, though better use whitespace or separate arguments for that.
List of log ﬂag mnemonics, with their counter form where applicable (asterisk indicates defaults): enabled*, disabled

Enables or disables logging. buffered, unbuffered*

Enabling buffering of log output before it hits the destinations. writethrough(/writethru) Whether to open the destination ﬁle with writethru buffering settings or not. flush Enables ﬂushing of the output ﬁle (to disk) after each log statement. lockcnts Preﬁx each log line with lock counts for the current thread. cpuid Preﬁx each log line with the ID of the current CPU. pid Preﬁx each log line with the current process ID. flagno Preﬁx each log line with the numberic ﬂags corresponding to the log statement. flag Preﬁx each log line with the ﬂag mnemonics corresponding to the log statement. groupno Preﬁx each log line with the log group number for the log statement producing it. group Preﬁx each log line with the log group name for the log statement producing it. tid Preﬁx each log line with the current thread identiﬁer. thread Preﬁx each log line with the current thread name. time Preﬁx each log line with the current UTC wall time. timeprog Preﬁx each log line with the current monotonic time since the start of the program. msprog Preﬁx each log line with the current monotonic timestamp value in milliseconds since the start of the program. ts Preﬁx each log line with the current monotonic timestamp value in nanoseconds. tsc Preﬁx each log line with the current CPU timestamp counter (TSC) value.

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8 VBoxManage rel, abs*

Selects the whether ts and tsc preﬁxes should be displayed as relative to the previous log line or as absolute time. hex*, dec

Selects the whether the ts and tsc preﬁxes should be formatted as hexadecimal or decimal. custom Custom log preﬁx, has by default no meaning for VM processes. usecrlf, uself*

Output with DOS style (CRLF) or just UNIX style (LF) line endings. overwrite*, append

Overwrite the destination ﬁle or append to it.
This corresponds to the logflags command in the debugger. debugvm osdetect
VBoxManage debugvm <uuid|vmname> osdetect

Make the VMM’s debugger facility (re)-detect the guest operating system (OS). This will ﬁrst load all debugger plug-ins.
This corresponds to the detect command in the debugger. debugvm osinfo
VBoxManage debugvm <uuid|vmname> osinfo

Displays information about the guest operating system (OS) previously detected by the VMM’s debugger facility. debugvm osdmesg
VBoxManage debugvm <uuid|vmname> osdmesg [--lines=lines]

Displays the guest OS kernel log, if detected and supported.
--lines=lines

Number of lines of the log to display, counting from the end. The default is inﬁnite. debugvm getregisters
VBoxManage debugvm <uuid|vmname> getregisters [--cpu=id] [reg-set.reg-name...]

Retrieves register values for guest CPUs and emulated devices. reg-set.reg-name One of more registers, each having one of the following forms:
1. register-set.register-name.sub-ﬁeld
2. register-set.register-name
3. cpu-register-name.sub-ﬁeld
4. cpu-register-name

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5. all
The all form will cause all registers to be shown (no sub-ﬁelds). The registers names are case-insensitive. --cpu=id

Selects the CPU register set when specifying just a CPU register (3rd and 4th form). The default is 0. debugvm setregisters
VBoxManage debugvm <uuid|vmname> setregisters [--cpu=id] [reg-set.reg-name=value...]

Changes register values for guest CPUs and emulated devices. reg-set.reg-name=value One of more register assignment, each having one of the following forms:
1. register-set.register-name.sub-ﬁeld=value
2. register-set.register-name=value
3. cpu-register-name.sub-ﬁeld=value
4. cpu-register-name=value
The value format should be in the same style as what getregisters displays, with the exception that both octal and decimal can be used instead of hexadecimal.
--cpu id

Selects the CPU register set when specifying just a CPU register (3rd and 4th form). The default is 0. debugvm show
VBoxManage debugvm <uuid|vmname> show [[--human-readable] | [--sh-export] |
[--sh-eval] | [--cmd-set]] [settings-item...]

Shows logging settings for the VM.
--human-readable

Selects human readable output.
--sh-export

Selects output format as bourne shell style export commands.
--sh-eval

Selects output format as bourne shell style eval command input.
--cmd-set

Selects output format as DOS style SET commands. settings-item What to display. One or more of the following:
• logdbg-settings - debug log settings.
• logrel-settings - release log settings.
• log-settings - alias for both debug and release log settings.

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VBoxManage debugvm <uuid|vmname> statistics [--reset] [--descriptions] [--pattern=pattern]

Displays or resets VMM statistics.
Retrieves register values for guest CPUs and emulated devices.
--pattern=pattern

DOS/NT-style wildcards patterns for selecting statistics. Multiple patterns can be speciﬁed by using the ’|’ (pipe) character as separator.
--reset

Select reset instead of display mode.

8.36 VBoxManage extpack
Extension package management.

Synopsis
VBoxManage extpack install [--replace] <tarball>
VBoxManage extpack uninstall [--force] <name>
VBoxManage extpack cleanup

Description extpack install
VBoxManage extpack install [--replace] <tarball>

Installs a new extension pack on the system. This command will fail if an older version of the same extension pack is already installed. The --replace option can be used to uninstall any old package before the new one is installed.
--replace

Uninstall existing extension pack version. tarball The ﬁle containing the extension pack to be installed. extpack uninstall
VBoxManage extpack uninstall [--force] <name>

Uninstalls an extension pack from the system. The subcommand will also succeed in the case where the speciﬁed extension pack is not present on the system. You can use VBoxManage list extpacks to show the names of the extension packs which are currently installed.
--force

Overrides most refusals to uninstall an extension pack name The name of the extension pack to be uninstalled.

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8 VBoxManage extpack cleanup
VBoxManage extpack cleanup

Used to remove temporary ﬁles and directories that may have been left behind if a previous install or uninstall command failed.

Examples
How to list extension packs:
$ VBoxManage list extpacks
Extension Packs: 1
Pack no. 0:
Oracle VM VirtualBox Extension Pack
Version:
4.1.12
Revision:
77218
Edition:
Description: USB 2.0 Host Controller, VirtualBox RDP, PXE ROM with E1000 support.
VRDE Module: VBoxVRDP
Usable:
true
Why unusable:

How to remove an extension pack:
$ VBoxManage extpack uninstall "Oracle VM VirtualBox Extension Pack"
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%
Successfully uninstalled "Oracle VM VirtualBox Extension Pack".

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9 Advanced topics
9.1 VBoxSDL, the simpliﬁed VM displayer
9.1.1 Introduction
VBoxSDL is a simple graphical user interface (GUI) that lacks the nice point-and-click support which VirtualBox, our main GUI, provides. VBoxSDL is currently primarily used internally for debugging VirtualBox and therefore not ofﬁcially supported. Still, you may ﬁnd it useful for environments where the virtual machines are not necessarily controlled by the same person that uses the virtual machine.
Note: VBoxSDL is not available on the Mac OS X host platform.
As you can see in the following screenshot, VBoxSDL does indeed only provide a simple window that contains only the “pure” virtual machine, without menus or other controls to click upon and no additional indicators of virtual machine activity:

To start a virtual machine with VBoxSDL instead of the VirtualBox GUI, enter the following on a command line:
VBoxSDL --startvm <vm>

where <vm> is, as usual with VirtualBox command line parameters, the name or UUID of an existing virtual machine.

9.1.2 Secure labeling with VBoxSDL
When running guest operating systems in full screen mode, the guest operating system usually has control over the whole screen. This could present a security risk as the guest operating

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9 Advanced topics system might fool the user into thinking that it is either a different system (which might have a higher security level) or it might present messages on the screen that appear to stem from the host operating system.
In order to protect the user against the above mentioned security risks, the secure labeling feature has been developed. Secure labeling is currently available only for VBoxSDL. When enabled, a portion of the display area is reserved for a label in which a user deﬁned message is displayed. The label height in set to 20 pixels in VBoxSDL. The label font color and background color can be optionally set as hexadecimal RGB color values. The following syntax is used to enable secure labeling:
VBoxSDL --startvm "VM name"
--securelabel --seclabelfnt ~/fonts/arial.ttf
--seclabelsiz 14 --seclabelfgcol 00FF00 --seclabelbgcol 00FFFF

In addition to enabling secure labeling, a TrueType font has to be supplied. To use another font size than 12 point use the parameter --seclabelsiz.
The label text can be set with
VBoxManage setextradata "VM name" "VBoxSDL/SecureLabel" "The Label"

Changing this label will take effect immediately.
Typically, full screen resolutions are limited to certain “standard” geometries such as 1024 x
768. Increasing this by twenty lines is not usually feasible, so in most cases, VBoxSDL will chose the next higher resolution, e.g. 1280 x 1024 and the guest’s screen will not cover the whole display surface. If VBoxSDL is unable to choose a higher resolution, the secure label will be painted on top of the guest’s screen surface. In order to address the problem of the bottom part of the guest screen being hidden, VBoxSDL can provide custom video modes to the guest that are reduced by the height of the label. For Windows guests and recent Solaris and Linux guests, the VirtualBox Guest Additions automatically provide the reduced video modes. Additionally, the VESA BIOS has been adjusted to duplicate its standard mode table with adjusted resolutions.
The adjusted mode IDs can be calculated using the following formula: reduced_modeid = modeid + 0x30

For example, in order to start Linux with 1024 x 748 x 16, the standard mode 0x117 (1024 x 768 x 16) is used as a base. The Linux video mode kernel parameter can then be calculated using: vga = 0x200 | 0x117 + 0x30 vga = 839

The reason for duplicating the standard modes instead of only supplying the adjusted modes is that most guest operating systems require the standard VESA modes to be ﬁxed and refuse to start with different modes.
When using the X.org VESA driver, custom modelines have to be calculated and added to the conﬁguration (usually in /etc/X11/xorg.conf. A handy tool to determine modeline entries can be found at http://www.tkk.fi/Misc/Electronics/faq/vga2rgb/calc.html.)

9.1.3 Releasing modiﬁers with VBoxSDL on Linux
When switching from a X virtual terminal (VT) to another VT using Ctrl-Alt-Fx while the
VBoxSDL window has the input focus, the guest will receive Ctrl and Alt keypress events without receiving the corresponding key release events. This is an architectural limitation of Linux. In order to reset the modiﬁer keys, it is possible to send SIGUSR1 to the VBoxSDL main thread (ﬁrst entry in the ps list). For example, when switching away to another VT and saving the virtual machine from this terminal, the following sequence can be used to make sure the VM is not saved with stuck modiﬁers: kill -usr1 <pid>
VBoxManage controlvm "Windows 2000" savestate

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9.2 Automated guest logons
VirtualBox provides Guest Addition modules for Windows, Linux and Solaris to enable automated logons on the guest.
When a guest operating system is running in a virtual machine, it might be desirable to perform coordinated and automated logons using credentials from a master logon system. (With “credentials”, we are referring to logon information consisting of user name, password and domain name, where each value might be empty.)

9.2.1 Automated Windows guest logons
Since Windows NT, Windows has provided a modular system logon subsystem (“Winlogon”) which can be customized and extended by means of so-called GINA modules (Graphical Identiﬁcation and Authentication). With Windows Vista and Windows 7, the GINA modules were replaced with a new mechanism called “credential providers”. The VirtualBox Guest Additions for Windows come with both, a GINA and a credential provider module, and therefore enable any Windows guest to perform automated logons.
To activate the VirtualBox GINA or credential provider module, install the Guest Additions with using the command line switch /with_autologon. All the following manual steps required for installing these modules will be then done by the installer.
To manually install the VirtualBox GINA module, extract the Guest Additions (see chapter 4.2.1.4, Manual ﬁle extraction, page 64) and copy the ﬁle VBoxGINA.dll to the Windows
SYSTEM32 directory. Then, in the registry, create the following key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\GinaDLL

with a value of VBoxGINA.dll.
Note: The VirtualBox GINA module is implemented as a wrapper around the standard
Windows GINA module (MSGINA.DLL). As a result, it will most likely not work correctly with 3rd party GINA modules.
To manually install the VirtualBox credential provider module, extract the Guest Additions
(see chapter 4.2.1.4, Manual ﬁle extraction, page 64) and copy the ﬁle VBoxCredProv.dll to the Windows SYSTEM32 directory. Then, in the registry, create the following keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\
Authentication\Credential Providers\{275D3BCC-22BB-4948-A7F6-3A3054EBA92B}
HKEY_CLASSES_ROOT\CLSID\{275D3BCC-22BB-4948-A7F6-3A3054EBA92B}
HKEY_CLASSES_ROOT\CLSID\{275D3BCC-22BB-4948-A7F6-3A3054EBA92B}\InprocServer32

with all default values (the key named (Default) in each key) set to VBoxCredProv. After that a new string named
HKEY_CLASSES_ROOT\CLSID\{275D3BCC-22BB-4948-A7F6-3A3054EBA92B}\InprocServer32\ThreadingModel

with a value of Apartment has to be created.
To set credentials, use the following command on a running VM:
VBoxManage controlvm "Windows XP" setcredentials "John Doe" "secretpassword" "DOMTEST"

While the VM is running, the credentials can be queried by the VirtualBox logon modules
(GINA or credential provider) using the VirtualBox Guest Additions device driver. When Windows is in “logged out” mode, the logon modules will constantly poll for credentials and if they

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9 Advanced topics are present, a logon will be attempted. After retrieving the credentials, the logon modules will erase them so that the above command will have to be repeated for subsequent logons.
For security reasons, credentials are not stored in any persistent manner and will be lost when the VM is reset. Also, the credentials are “write-only”, i.e. there is no way to retrieve the credentials from the host side. Credentials can be reset from the host side by setting empty values. Depending on the particular variant of the Windows guest, the following restrictions apply:
1. For Windows XP guests, the logon subsystem needs to be conﬁgured to use the classic logon dialog as the VirtualBox GINA module does not support the XP-style welcome dialog.
2. For Windows Vista, Windows 7 and Windows 8 guests, the logon subsystem does not support the so-called Secure Attention Sequence (CTRL+ALT+DEL). As a result, the guest’s group policy settings need to be changed to not use the Secure Attention Sequence. Also, the user name given is only compared to the true user name, not the user friendly name.
This means that when you rename a user, you still have to supply the original user name
(internally, Windows never renames user accounts).
3. Auto-logon handling of the built-in Windows Remote Desktop Service (formerly known as
Terminal Services) is disabled by default. To enable it, create the registry key
HKEY_LOCAL_MACHINE\SOFTWARE\Oracle\VirtualBox Guest Additions\AutoLogon

with a DWORD value of 1.
The following command forces VirtualBox to keep the credentials after they were read by the guest and on VM reset:
VBoxManage setextradata "Windows XP" VBoxInternal/Devices/VMMDev/0/Config/KeepCredentials 1

Note that this is a potential security risk as a malicious application running on the guest could request this information using the proper interface.

9.2.2 Automated Linux/Unix guest logons
Starting with version 3.2, VirtualBox provides a custom PAM module (Pluggable Authentication
Module) which can be used to perform automated guest logons on platforms which support this framework. Virtually all modern Linux/Unix distributions rely on PAM.
For automated logons on Ubuntu (or Ubuntu-derived) distributions using LightDM as the display manager, please see chapter 9.2.2.1, VirtualBox Greeter for Ubuntu / LightDM, page 176.
The pam_vbox.so module itself does not do an actual veriﬁcation of the credentials passed to the guest OS; instead it relies on other modules such as pam_unix.so or pam_unix2.so down in the PAM stack to do the actual validation using the credentials retrieved by pam_vbox.so.
Therefore pam_vbox.so has to be on top of the authentication PAM service list.
Note: The pam_vbox.so only supports the auth primitive. Other primitives such as account, session or password are not supported.
The pam_vbox.so module is shipped as part of the Guest Additions but it is not installed and/or activated on the guest OS by default. In order to install it, it has to be copied from
/opt/VBoxGuestAdditions-<version>/lib/VBoxGuestAdditions/ to the security modules directory, usually /lib/security/ on 32-bit guest Linuxes or /lib64/security/ on 64-bit ones. Please refer to your guest OS documentation for the correct PAM module directory.
For example, to use pam_vbox.so with a Ubuntu Linux guest OS and GDM (the GNOME
Desktop Manager) to logon users automatically with the credentials passed by the host, the guest OS has to be conﬁgured like the following:

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1. The pam_vbox.so module has to be copied to the security modules directory, in this case it is /lib/security.
2. Edit the PAM conﬁguration ﬁle for GDM found at /etc/pam.d/gdm, adding the line auth requisite pam_vbox.so at the top. Additionaly, in most Linux distributions there is a ﬁle called /etc/pam.d/common-auth. This ﬁle is included in many other services (like the GDM ﬁle mentioned above). There you also have to add the line auth requisite pam_vbox.so. 3. If authentication against the shadow database using pam_unix.so or pam_unix2.so is desired, the argument try_first_pass for pam_unix.so or use_first_pass for pam_unix2.so is needed in order to pass the credentials from the VirtualBox module to the shadow database authentication module. For Ubuntu, this needs to be added to
/etc/pam.d/common-auth, to the end of the line referencing pam_unix.so. This argument tells the PAM module to use credentials already present in the stack, i.e. the ones provided by the VirtualBox PAM module.

Warning: An incorrectly conﬁgured PAM stack can effectively prevent you from logging into your guest system!
To make deployment easier, you can pass the argument debug right after the pam_vbox.so statement. Debug log output will then be recorded using syslog.
Note: By default, pam_vbox will not wait for credentials to arrive from the host, in other words: When a login prompt is shown (for example by GDM/KDM or the text console) and pam_vbox does not yet have credentials it does not wait until they arrive.
Instead the next module in the PAM stack (depending on the PAM conﬁguration) will have the chance for authentication.
Starting with VirtualBox 4.1.4 pam_vbox supports various guest property parameters which all reside in /VirtualBox/GuestAdd/PAM/. These parameters allow pam_vbox to wait for credentials to be provided by the host and optionally can show a message while waiting for those.
The following guest properties can be set:
1. CredsWait: Set to “1” if pam_vbox should start waiting until credentials arrive from the host. Until then no other authentication methods such as manually logging in will be available. If this property is empty or get deleted no waiting for credentials will be performed and pam_vbox will act like before (see paragraph above). This property must be set read-only for the guest (RDONLYGUEST).
2. CredsWaitAbort: Aborts waiting for credentials when set to any value. Can be set from host and the guest.
3. CredsWaitTimeout: Timeout (in seconds) to let pam_vbox wait for credentials to arrive.
When no credentials arrive within this timeout, authentication of pam_vbox will be set to failed and the next PAM module in chain will be asked. If this property is not speciﬁed, set to “0” or an invalid value, an inﬁnite timeout will be used. This property must be set read-only for the guest (RDONLYGUEST).
To customize pam_vbox further there are the following guest properties:
1. CredsMsgWaiting: Custom message showed while pam_vbox is waiting for credentials from the host. This property must be set read-only for the guest (RDONLYGUEST).

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2. CredsMsgWaitTimeout: Custom message showed when waiting for credentials by pam_vbox timed out, e.g. did not arrive within time. This property must be set readonly for the guest (RDONLYGUEST).

Note: If a pam_vbox guest property does not have set the right ﬂags (RDONLYGUEST) this property will be ignored then and - depending on the property - a default value will be set. This can result in pam_vbox not waiting for credentials. Consult the appropriate syslog ﬁle for more information and use the debug option.

9.2.2.1 VirtualBox Greeter for Ubuntu / LightDM
Starting with version 4.2.12, VirtualBox comes with an own greeter module named vbox-greeter which can be used with LightDM 1.0.1 or later. LightDM is the default display manager since
Ubuntu 10.11 and therefore also can be used for automated guest logons. vbox-greeter does not need the pam_vbox module described above in order to function – it comes with its own authentication mechanism provided by LightDM. However, to provide maximum of ﬂexibility both modules can be used together on the same guest.
As for the pam_vbox module, vbox-greeter is shipped as part of the Guest Additions but it is not installed and/or activated on the guest OS by default For installing vbox-greeter automatically upon Guest Additions installation, use the --with-autologon switch when starting the
VBoxLinuxAdditions.run ﬁle:
# ./VBoxLinuxAdditions.run -- --with-autologon

For manual or postponed installation, the vbox-greeter.desktop ﬁle has to be copied from
/opt/VBoxGuestAdditions-<version>/shared/VBoxGuestAdditions/ to the xgreeters directory, usually /usr/share/xgreeters/. Please refer to your guest OS documentation for the correct LightDM greeter directory.
The vbox-greeter module itself already was installed by the VirtualBox Guest Additions installer and resides in /usr/sbin/. To enable vbox-greeter as the standard greeter module, the ﬁle /etc/lightdm/lightdm.conf needs to be edited:
[SeatDefaults]
greeter-session=vbox-greeter

Note: The LightDM server needs to be fully restarted in order to get vbox-greeter used as the default greeter. As root, do a service lightdm --full-restart on Ubuntu, or simply restart the guest.

Note: vbox-greeter is independent of the graphical session chosen by the user (like
Gnome, KDE, Unity etc). However, it requires FLTK 1.3 for representing its own user interface. There are numerous guest properties which can be used to further customize the login experience. For automatically logging in users, the same guest properties apply as for pam_vbox, see chapter 9.2.2, Automated Linux/Unix guest logons, page 174.
In addition to the above mentioned guest properties, vbox-greeter allows further customization of its user interface. These special guest properties all reside in /VirtualBox/GuestAdd/Greeter/:

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1. HideRestart: Set to “1” if vbox-greeter should hide the button to restart the guest. This property must be set read-only for the guest (RDONLYGUEST).
2. HideShutdown: Set to “1” if vbox-greeter should hide the button to shutdown the guest.
This property must be set read-only for the guest (RDONLYGUEST).
3. BannerPath: Path to a .PNG ﬁle for using it as a banner on the top. The image size must be 460 x 90 pixels, any bit depth. This property must be set read-only for the guest
(RDONLYGUEST).
4. UseTheming: Set to “1” for turning on the following theming options. This property must be set read-only for the guest (RDONLYGUEST).
5. Theme/BackgroundColor: Hexadecimal RRGGBB color for the background. This property must be set read-only for the guest (RDONLYGUEST).
6. Theme/LogonDialog/HeaderColor: Hexadecimal RRGGBB foreground color for the header text. This property must be set read-only for the guest (RDONLYGUEST).
7. Theme/LogonDialog/BackgroundColor: Hexadecimal RRGGBB color for the logon dialog background. This property must be set read-only for the guest (RDONLYGUEST).
8. Theme/LogonDialog/ButtonColor: Hexadecimal RRGGBB background color for the logon dialog button. This property must be set read-only for the guest (RDONLYGUEST).
Note: The same restrictions for the guest properties above apply as for the ones speciﬁed in the pam_vbox section.

9.3 Advanced conﬁguration for Windows guests
9.3.1 Automated Windows system preparation
Beginning with Windows NT 4.0, Microsoft offers a “system preparation” tool (in short: Sysprep) to prepare a Windows system for deployment or redistribution. Whereas Windows 2000 and
XP ship with Sysprep on the installation medium, the tool also is available for download on the Microsoft web site. In a standard installation of Windows Vista and 7, Sysprep is already included. Sysprep mainly consists of an executable called sysprep.exe which is invoked by the user to put the Windows installation into preparation mode.
Starting with VirtualBox 3.2.2, the Guest Additions offer a way to launch a system preparation on the guest operating system in an automated way, controlled from the host system. To achieve that, see chapter 4.8, Guest control, page 78 for using the feature with the special identiﬁer sysprep as the program to execute, along with the user name sysprep and password sysprep for the credentials. Sysprep then gets launched with the required system rights.
Note: Specifying the location of “sysprep.exe” is not possible – instead the following paths are used (based on the operating system):
• C:\sysprep\sysprep.exe for Windows NT 4.0, 2000 and XP
• %WINDIR%\System32\Sysprep\sysprep.exe for Windows Vista, 2008 Server and 7
The Guest Additions will automatically use the appropriate path to execute the system preparation tool.

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9.4 Advanced conﬁguration for Linux and Solaris guests
9.4.1 Manual setup of selected guest services on Linux
The VirtualBox Guest Additions contain several different drivers. If for any reason you do not wish to set them all up, you can install the Guest Additions using the following command: sh ./VBoxLinuxAdditions.run no_setup

After this, you will need to at least compile the kernel modules by running the command rcvboxadd setup

as root (you will need to replace lib by lib64 on some 64bit guests), and on older guests without the udev service you will need to add the vboxadd service to the default runlevel to ensure that the modules get loaded.
To setup the time synchronization service, add the service vboxadd-service to the default runlevel. To set up the X11 and OpenGL part of the Guest Additions, run the command rcvboxadd-x11 setup

(you do not need to enable any services for this).
To recompile the guest kernel modules, use this command: rcvboxadd setup

After compilation you should reboot your guest to ensure that the new modules are actually used. 9.4.2 Guest graphics and mouse driver setup in depth
This section assumes that you are familiar with conﬁguring the X.Org server using xorg.conf and optionally the newer mechanisms using hal or udev and xorg.conf.d. If not you can learn about them by studying the documentation which comes with X.Org.
The VirtualBox Guest Additions come with drivers for X.Org versions
• X11R6.8/X11R6.9 and XFree86 version 4.3 (vboxvideo_drv_68.o and vboxmouse_drv_68.o)
• X11R7.0 (vboxvideo_drv_70.so and vboxmouse_drv_70.so)
• X11R7.1 (vboxvideo_drv_71.so and vboxmouse_drv_71.so)
• X.Org Server versions 1.3 and later (vboxvideo_drv_13.so and vboxmouse_drv_13.so and so on).
By default these drivers can be found in the directory
/opt/VBoxGuestAdditions-<version>/lib/VBoxGuestAdditions

and the correct versions for the X server are symbolically linked into the X.Org driver directories.
For graphics integration to work correctly, the X server must load the vboxvideo driver (many recent X server versions look for it automatically if they see that they are running in VirtualBox) and for an optimal user experience the guest kernel drivers must be loaded and the Guest Additions tool VBoxClient must be running as a client in the X session. For mouse integration to work correctly, the guest kernel drivers must be loaded and in addition, in X servers from X.Org
X11R6.8 to X11R7.1 and in XFree86 version 4.3 the right vboxmouse driver must be loaded and associated with /dev/mouse or /dev/psaux; in X.Org server 1.3 or later a driver for a PS/2 mouse must be loaded and the right vboxmouse driver must be associated with /dev/vboxguest.

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The VirtualBox guest graphics driver can use any graphics conﬁguration for which the virtual resolution ﬁts into the virtual video memory allocated to the virtual machine (minus a small amount used by the guest driver) as described in chapter 3.5, Display settings, page 50. The driver will offer a range of standard modes at least up to the default guest resolution for all active guest monitors. In X.Org Server 1.3 and later the default mode can be changed by setting the output property VBOX_MODE to “<width>x<height>“ for any guest monitor. When VBoxClient and the kernel drivers are active this is done automatically when the host requests a mode change.
The driver for older versions can only receive new modes by querying the host for requests at regular intervals.
With pre-1.3 X Servers you can also add your own modes to the X server conﬁguration ﬁle. You simply need to add them to the “Modes” list in the “Display” subsection of the “Screen” section.
For example, the section shown here has a custom 2048x800 resolution mode added:
Section "Screen"
Identifier
"Default Screen"
Device
"VirtualBox graphics card"
Monitor
"Generic Monitor"
DefaultDepth 24
SubSection "Display"
Depth
24
Modes
"2048x800" "800x600" "640x480"
EndSubSection
EndSection

9.5 CPU hot-plugging
With virtual machines running modern server operating systems, VirtualBox supports CPU hotplugging.1 Whereas on a physical computer this would mean that a CPU can be added or removed while the machine is running, VirtualBox supports adding and removing virtual CPUs while a virtual machine is running.
CPU hot-plugging works only with guest operating systems that support it. So far this applies only to Linux and Windows Server 2008 x64 Data Center Edition. Windows supports only hotadd while Linux supports hot-add and hot-remove but to use this feature with more than 8 CPUs a 64bit Linux guest is required.
At this time, CPU hot-plugging requires using the VBoxManage command-line interface. First, hot-plugging needs to be enabled for a virtual machine:
VBoxManage modifyvm "VM name" --cpuhotplug on

After that, the –cpus option speciﬁes the maximum number of CPUs that the virtual machine can have:
VBoxManage modifyvm "VM name" --cpus 8

When the VM is off, you can then add and remove virtual CPUs with the modifyvm –plugcpu and
–unplugcpu subcommands, which take the number of the virtual CPU as a parameter, like this:
VBoxManage modifyvm "VM name" --plugcpu 3
VBoxManage modifyvm "VM name" --unplugcpu 3

Note that CPU 0 can never be removed.
While the VM is running, CPUs can be added with the controlvm plugcpu/unplugcpu commands instead:
VBoxManage controlvm "VM name" plugcpu 3
VBoxManage controlvm "VM name" unplugcpu 3
1 Support

for CPU hot-plugging was introduced with VirtualBox 3.2.

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See chapter 8.8, VBoxManage modifyvm, page 129 and chapter 8.13, VBoxManage controlvm, page 140 for details.
With Linux guests, the following applies: To prevent ejection while the CPU is still used it has to be ejected from within the guest before. The Linux Guest Additions contain a service which receives hot-remove events and ejects the CPU. Also, after a CPU is added to the VM it is not automatically used by Linux. The Linux Guest Additions service will take care of that if installed.
If not a CPU can be started with the following command: echo 1 > /sys/devices/system/cpu/cpu<id>/online

9.6 PCI passthrough
When running on Linux hosts, with a recent enough kernel (at least version 2.6.31) experimental host PCI devices passthrough is available.2
Note: The PCI passthrough module is shipped as a VirtualBox extension package, which must be installed separately. See chapter 1.5, Installing VirtualBox and extension packs, page 15 for more information.
Essentially this feature allows to directly use physical PCI devices on the host by the guest even if host doesn’t have drivers for this particular device. Both, regular PCI and some PCI Express cards, are supported. AGP and certain PCI Express cards are not supported at the moment if they rely on GART (Graphics Address Remapping Table) unit programming for texture management as it does rather nontrivial operations with pages remapping interfering with IOMMU. This limitation may be lifted in future releases.
To be fully functional, PCI passthrough support in VirtualBox depends upon an IOMMU hardware unit which is not yet too widely available. If the device uses bus mastering (i.e. it performs
DMA to the OS memory on its own), then an IOMMU is required, otherwise such DMA transactions may write to the wrong physical memory address as the device DMA engine is programmed using a device-speciﬁc protocol to perform memory transactions. The IOMMU functions as translation unit mapping physical memory access requests from the device using knowledge of the guest physical address to host physical addresses translation rules.
Intel’s solution for IOMMU is marketed as “Intel Virtualization Technology for Directed I/O”
(VT-d), and AMD’s one is called AMD-Vi. So please check if your motherboard datasheet has appropriate technology. Even if your hardware doesn’t have a IOMMU, certain PCI cards may work (such as serial PCI adapters), but the guest will show a warning on boot and the VM execution will terminate if the guest driver will attempt to enable card bus mastering.
It is very common that the BIOS or the host OS disables the IOMMU by default. So before any attempt to use it please make sure that
1. Your motherboard has an IOMMU unit.
2. Your CPU supports the IOMMU.
3. The IOMMU is enabled in the BIOS.
4. The VM must run with VT-x/AMD-V and nested paging enabled.
5. Your Linux kernel was compiled with IOMMU support (including DMA remapping, see
CONFIG_DMAR kernel compilation option). The PCI stub driver (CONFIG_PCI_STUB) is required as well.

2 Experimental

support for PCI passthrough was introduced with VirtualBox 4.1.

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6. Your Linux kernel recognizes and uses the IOMMU unit (intel_iommu=on boot option could be needed). Search for DMAR and PCI-DMA in kernel boot log.
Once you made sure that the host kernel supports the IOMMU, the next step is to select the
PCI card and attach it to the guest. To ﬁgure out the list of available PCI devices, use the lspci command. The output will look like this:
01:00.0 VGA compatible controller: ATI Technologies Inc Cedar PRO [Radeon HD 5450]
01:00.1 Audio device: ATI Technologies Inc Manhattan HDMI Audio [Mobility Radeon HD 5000 Series]
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit
Ethernet controller (rev 03)
03:00.0 SATA controller: JMicron Technology Corp. JMB362/JMB363 Serial ATA Controller (rev 03)
03:00.1 IDE interface: JMicron Technology Corp. JMB362/JMB363 Serial ATA Controller (rev 03)
06:00.0 VGA compatible controller: nVidia Corporation G86 [GeForce 8500 GT] (rev a1)

The ﬁrst column is a PCI address (in format bus:device.function). This address could be used to identify the device for further operations. For example, to attach a PCI network controller on the system listed above to the second PCI bus in the guest, as device 5, function 0, use the following command:
VBoxManage modifyvm "VM name" --pciattach 02:00.0@01:05.0

To detach same device, use
VBoxManage modifyvm "VM name" --pcidetach 02:00.0

Please note that both host and guest could freely assign a different PCI address to the card attached during runtime, so those addresses only apply to the address of the card at the moment of attachment (host), and during BIOS PCI init (guest).
If the virtual machine has a PCI device attached, certain limitations apply:
1. Only PCI cards with non-shared interrupts (such as using MSI on host) are supported at the moment.
2. No guest state can be reliably saved/restored (as the internal state of the PCI card could not be retrieved).
3. Teleportation (live migration) doesn’t work (for the same reason).
4. No lazy physical memory allocation. The host will preallocate the whole RAM required for the VM on startup (as we cannot catch physical hardware accesses to the physical memory).

9.7 Webcam passthrough
9.7.1 Using a host webcam in the guest
VirtualBox 4.3 includes an experimental feature which allows a guest to use a host webcam.
This complements the general USB passthrough support which was the typical way of using host webcams in earlier versions. The webcam passthrough support can handle non-USB video sources in theory, but this is completely untested.
Note: The webcam passthrough module is shipped as part of the Oracle VM VirtualBox extension pack, which must be installed separately. See chapter 1.5, Installing
VirtualBox and extension packs, page 15 for more information.

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The host webcam can be attached to the VM using “Devices” menu in the VM menu bar. The
“Webcams” menu contains a list of available video input devices on the host. Clicking on a webcam name attaches or detaches the corresponding host device.
The VBoxManage command line tool can be used to enable webcam passthrough. Please see the host-speciﬁc sections below for additional details. The following commands are available:
• Get a list of host webcams (or other video input devices):
VBoxManage list webcams

The output format: alias "user friendly name" host path or identifier

The alias can be used as a shortcut in other commands. Alias ’.0’ means default video input device on the host, ’.1’, ’.2’, etc mean ﬁrst, second, etc video input device. The device order is host-speciﬁc.
• Attach a webcam to a running VM:
VBoxManage controlvm "VM name" webcam attach [host_path|alias [settings]]

This will attach a USB webcam device to the guest.
The settings parameter is a string Setting1=Value1;Setting2=Value2, which allows to conﬁgure the emulated webcam device. The following settings are supported:
– MaxFramerate The highest rate at which video frames are sent to the guest. A higher frame rate requires more CPU power. Therefore sometimes it is useful to set a lower limit. Default is no limit and allow the guest to use all frame rates supported by the host webcam.
– MaxPayloadTransferSize How many bytes the emulated webcam can send to the guest at a time. Default value is 3060 bytes, which is used by some webcams. Higher values can slightly reduce CPU load, if the guest is able to use larger buffers. However, a high MaxPayloadTransferSize might be not supported by some guests.
• Detach a webcam from a running VM:
VBoxManage controlvm "VM name" webcam detach [host_path|alias]

• List webcams attached to a running VM:
VBoxManage controlvm "VM name" webcam list

The output contains path or alias which was used in ’webcam attach’ command for each attached webcam.

9.7.2 Windows hosts
When the webcam device is detached from the host, the emulated webcam device is automatically detached from the guest.

9.7.3 Mac OS X hosts
OS X version 10.7 or newer is required.
When the webcam device is detached from the host, the emulated webcam device remains attached to the guest and must be manually detached using the VBoxManage controlvm "VM name" webcam detach ... command.

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9.7.4 Linux and Solaris hosts
When the webcam is detached from the host the emulated webcam device is automatically detached from the guest only if the webcam is streaming video. If the emulated webcam is inactive it should be manually detached using the VBoxManage controlvm "VM name" webcam detach
... command.
Aliases .0 and .1 are mapped to /dev/video0, alias .2 is mapped to /dev/video1 and so forth. 9.8 Advanced display conﬁguration
9.8.1 Custom VESA resolutions
Apart from the standard VESA resolutions, the VirtualBox VESA BIOS allows you to add up to 16 custom video modes which will be reported to the guest operating system. When using Windows guests with the VirtualBox Guest Additions, a custom graphics driver will be used instead of the fallback VESA solution so this information does not apply.
Additional video modes can be conﬁgured for each VM using the extra data facility. The extra data key is called CustomVideoMode<x> with x being a number from 1 to 16. Please note that modes will be read from 1 until either the following number is not deﬁned or 16 is reached. The following example adds a video mode that corresponds to the native display resolution of many notebook computers:
VBoxManage setextradata "VM name" "CustomVideoMode1" "1400x1050x16"

The VESA mode IDs for custom video modes start at 0x160. In order to use the above deﬁned custom video mode, the following command line has be supplied to Linux: vga = 0x200 | 0x160 vga = 864

For guest operating systems with VirtualBox Guest Additions, a custom video mode can be set using the video mode hint feature.

9.8.2 Conﬁguring the maximum resolution of guests when using the graphical frontend
When guest systems with the Guest Additions installed are started using the graphical frontend
(the normal VirtualBox application), they will not be allowed to use screen resolutions greater than the host’s screen size unless the user manually resizes them by dragging the window, switching to full screen or seamless mode or sending a video mode hint using VBoxManage. This behavior is what most users will want, but if you have different needs, it is possible to change it by issuing one of the following commands from the command line:
VBoxManage setextradata global GUI/MaxGuestResolution any

will remove all limits on guest resolutions.
VBoxManage setextradata global GUI/MaxGuestResolution >width,height<

manually speciﬁes a maximum resolution.
VBoxManage setextradata global GUI/MaxGuestResolution auto

restores the default settings. Note that these settings apply globally to all guest systems, not just to a single machine.

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9.9 Advanced storage conﬁguration
9.9.1 Using a raw host hard disk from a guest
Starting with version 1.4, as an alternative to using virtual disk images (as described in detail in chapter 5, Virtual storage, page 81), VirtualBox can also present either entire physical hard disks or selected partitions thereof as virtual disks to virtual machines.
With VirtualBox, this type of access is called “raw hard disk access”; it allows a guest operating system to access its virtual hard disk without going through the host OS ﬁle system. The actual performance difference for image ﬁles vs. raw disk varies greatly depending on the overhead of the host ﬁle system, whether dynamically growing images are used, and on host OS caching strategies. The caching indirectly also affects other aspects such as failure behavior, i.e. whether the virtual disk contains all data written before a host OS crash. Consult your host OS documentation for details on this.
Warning: Raw hard disk access is for expert users only. Incorrect use or use of an outdated conﬁguration can lead to total loss of data on the physical disk. Most importantly, do not attempt to boot the partition with the currently running host operating system in a guest. This will lead to severe data corruption.
Raw hard disk access – both for entire disks and individual partitions – is implemented as part of the VMDK image format support. As a result, you will need to create a special VMDK image ﬁle which deﬁnes where the data will be stored. After creating such a special VMDK image, you can use it like a regular virtual disk image. For example, you can use the VirtualBox Manager
(chapter 5.3, The Virtual Media Manager, page 85) or VBoxManage to assign the image to a virtual machine. 9.9.1.1 Access to entire physical hard disk
While this variant is the simplest to set up, you must be aware that this will give a guest operating system direct and full access to an entire physical disk. If your host operating system is also booted from this disk, please take special care to not access the partition from the guest at all. On the positive side, the physical disk can be repartitioned in arbitrary ways without having to recreate the image ﬁle that gives access to the raw disk.
To create an image that represents an entire physical hard disk (which will not contain any actual data, as this will all be stored on the physical disk), on a Linux host, use the command
VBoxManage internalcommands createrawvmdk -filename /path/to/file.vmdk
-rawdisk /dev/sda

This creates the image /path/to/file.vmdk (must be absolute), and all data will be read and written from /dev/sda.
On a Windows host, instead of the above device speciﬁcation, use e.g. \\.\PhysicalDrive0.
On a Mac OS X host, instead of the above device speciﬁcation use e.g. /dev/disk1. Note that on OS X you can only get access to an entire disk if no volume is mounted from it.
Creating the image requires read/write access for the given device. Read/write access is also later needed when using the image from a virtual machine. On some host platforms (e.g. Windows Vista and later), raw disk access may be restricted and not permitted by the host OS in some situations.
Just like with regular disk images, this does not automatically attach the newly created image to a virtual machine. This can be done with e.g.
VBoxManage storageattach WindowsXP --storagectl "IDE Controller"
--port 0 --device 0 --type hdd --medium /path/to/file.vmdk

When this is done the selected virtual machine will boot from the speciﬁed physical disk.

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9.9.1.2 Access to individual physical hard disk partitions
This “raw partition support” is quite similar to the “full hard disk” access described above. However, in this case, any partitioning information will be stored inside the VMDK image, so you can
e.g. install a different boot loader in the virtual hard disk without affecting the host’s partitioning information. While the guest will be able to see all partitions that exist on the physical disk, access will be ﬁltered in that reading from partitions for which no access is allowed the partitions will only yield zeroes, and all writes to them are ignored.
To create a special image for raw partition support (which will contain a small amount of data, as already mentioned), on a Linux host, use the command
VBoxManage internalcommands createrawvmdk -filename /path/to/file.vmdk
-rawdisk /dev/sda -partitions 1,5

As you can see, the command is identical to the one for “full hard disk” access, except for the additional -partitions parameter. This example would create the image /path/to/file.vmdk
(which, again, must be absolute), and partitions 1 and 5 of /dev/sda would be made accessible to the guest.
VirtualBox uses the same partition numbering as your Linux host. As a result, the numbers given in the above example would refer to the ﬁrst primary partition and the ﬁrst logical drive in the extended partition, respectively.
On a Windows host, instead of the above device speciﬁcation, use e.g. \\.\PhysicalDrive0.
On a Mac OS X host, instead of the above device speciﬁcation use e.g. /dev/disk1. Note that on OS X you can only use partitions which are not mounted (eject the respective volume ﬁrst).
Partition numbers are the same on Linux, Windows and Mac OS X hosts.
The numbers for the list of partitions can be taken from the output of
VBoxManage internalcommands listpartitions -rawdisk /dev/sda

The output lists the partition types and sizes to give the user enough information to identify the partitions necessary for the guest.
Images which give access to individual partitions are speciﬁc to a particular host disk setup.
You cannot transfer these images to another host; also, whenever the host partitioning changes, the image must be recreated.
Creating the image requires read/write access for the given device. Read/write access is also later needed when using the image from a virtual machine. If this is not feasible, there is a special variant for raw partition access (currently only available on Linux hosts) that avoids having to give the current user access to the entire disk. To set up such an image, use
VBoxManage internalcommands createrawvmdk -filename /path/to/file.vmdk
-rawdisk /dev/sda -partitions 1,5 -relative

When used from a virtual machine, the image will then refer not to the entire disk, but only to the individual partitions (in the example /dev/sda1 and /dev/sda5). As a consequence, read/write access is only required for the affected partitions, not for the entire disk. During creation however, read-only access to the entire disk is required to obtain the partitioning information.
In some conﬁgurations it may be necessary to change the MBR code of the created image, e.g. to replace the Linux boot loader that is used on the host by another boot loader. This allows e.g. the guest to boot directly to Windows, while the host boots Linux from the “same” disk. For this purpose the -mbr parameter is provided. It speciﬁes a ﬁle name from which to take the MBR code. The partition table is not modiﬁed at all, so a MBR ﬁle from a system with totally different partitioning can be used. An example of this is
VBoxManage internalcommands createrawvmdk -filename /path/to/file.vmdk
-rawdisk /dev/sda -partitions 1,5 -mbr winxp.mbr

The modiﬁed MBR will be stored inside the image, not on the host disk.
The created image can be attached to a storage controller in a VM conﬁguration as usual.

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9.9.2 Conﬁguring the hard disk vendor product data (VPD)
VirtualBox reports vendor product data for its virtual hard disks which consist of hard disk serial number, ﬁrmware revision and model number. These can be changed using the following commands: VBoxManage setextradata "VM name"
"VBoxInternal/Devices/ahci/0/Config/Port0/SerialNumber" "serial"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/ahci/0/Config/Port0/FirmwareRevision" "firmware"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/ahci/0/Config/Port0/ModelNumber" "model"

The serial number is a 20 byte alphanumeric string, the ﬁrmware revision an 8 byte alphanumeric string and the model number a 40 byte alphanumeric string. Instead of “Port0” (referring to the ﬁrst port), specify the desired SATA hard disk port.
The above commands apply to virtual machines with an AHCI (SATA) controller. The commands for virtual machines with an IDE controller are:
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/piix3ide/0/Config/PrimaryMaster/SerialNumber" "serial"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/piix3ide/0/Config/PrimaryMaster/FirmwareRevision" "firmware"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/piix3ide/0/Config/PrimaryMaster/ModelNumber" "model"

For hard disks it’s also possible to mark the drive as having a non-rotational medium with:
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/ahci/0/Config/Port0/NonRotational" "1"

Additional three parameters are needed for CD/DVD drives to report the vendor product data:
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/ahci/0/Config/Port0/ATAPIVendorId" "vendor"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/ahci/0/Config/Port0/ATAPIProductId" "product"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/ahci/0/Config/Port0/ATAPIRevision" "revision"

The vendor id is an 8 byte alphanumeric string, the product id an 16 byte alphanumeric string and the revision a 4 byte alphanumeric string. Instead of “Port0” (referring to the ﬁrst port), specify the desired SATA hard disk port.

9.9.3 Access iSCSI targets via Internal Networking
As an experimental feature, VirtualBox allows for accessing an iSCSI target running in a virtual machine which is conﬁgured for using Internal Networking mode. Please see chapter 5.10, iSCSI servers, page 92; chapter 6.6, Internal networking, page 100; and chapter 8.18, VBoxManage storageattach, page 144 for additional information.
The IP stack accessing Internal Networking must be conﬁgured in the virtual machine which accesses the iSCSI target. A free static IP and a MAC address not used by other virtual machines must be chosen. In the example below, adapt the name of the virtual machine, the MAC address, the IP conﬁguration and the Internal Networking name (“MyIntNet”) according to your needs.
The following eight commands must ﬁrst be issued:
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage
VBoxManage

setextradata setextradata setextradata setextradata setextradata setextradata setextradata setextradata "VM
"VM
"VM
"VM
"VM
"VM
"VM
"VM

name" name" name" name" name" name" name" name" VBoxInternal/Devices/IntNetIP/0/Trusted 1
VBoxInternal/Devices/IntNetIP/0/Config/MAC 08:00:27:01:02:0f
VBoxInternal/Devices/IntNetIP/0/Config/IP 10.0.9.1
VBoxInternal/Devices/IntNetIP/0/Config/Netmask 255.255.255.0
VBoxInternal/Devices/IntNetIP/0/LUN#0/Driver IntNet
VBoxInternal/Devices/IntNetIP/0/LUN#0/Config/Network MyIntNet
VBoxInternal/Devices/IntNetIP/0/LUN#0/Config/TrunkType 2
VBoxInternal/Devices/IntNetIP/0/LUN#0/Config/IsService 1

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Finally the iSCSI disk must be attached with the --intnet option to tell the iSCSI initiator to use internal networking:
VBoxManage storageattach ... --medium iscsi
--server 10.0.9.30 --target iqn.2008-12.com.sun:sampletarget --intnet

Compared to a “regular” iSCSI setup, IP address of the target must be speciﬁed as a numeric
IP address, as there is no DNS resolver for internal networking.
The virtual machine with the iSCSI target should be started before the VM using it is powered on. If a virtual machine using an iSCSI disk is started without having the iSCSI target powered up, it can take up to 200 seconds to detect this situation. The VM will fail to power up.

9.10 Legacy commands for using serial ports
Starting with version 1.4, VirtualBox provided support for virtual serial ports, which, at the time, was rather complicated to set up with a sequence of VBoxManage setextradata statements.
Since version 1.5, that way of setting up serial ports is no longer necessary and deprecated. To set up virtual serial ports, use the methods now described in chapter 3.9, Serial ports, page 53.
Note: For backwards compatibility, the old setextradata statements, whose description is retained below from the old version of the manual, take precedence over the new way of conﬁguring serial ports. As a result, if conﬁguring serial ports the new way doesn’t work, make sure the VM in question does not have old conﬁguration data such as below still active.
The old sequence of conﬁguring a serial port used the following 6 commands:
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/serial/0/Config/IRQ" 4
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/serial/0/Config/IOBase" 0x3f8
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/serial/0/LUN#0/Driver" Char
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/serial/0/LUN#0/AttachedDriver/Driver" NamedPipe
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/serial/0/LUN#0/AttachedDriver/Config/Location" "\\.\pipe\vboxCOM1"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/serial/0/LUN#0/AttachedDriver/Config/IsServer" 1

This sets up a serial port in the guest with the default settings for COM1 (IRQ 4, I/O address
0x3f8) and the Location setting assumes that this conﬁguration is used on a Windows host, because the Windows named pipe syntax is used. Keep in mind that on Windows hosts a named pipe must always start with \\.\pipe\. On Linux the same conﬁguration settings apply, except that the path name for the Location can be chosen more freely. Local domain sockets can be placed anywhere, provided the user running VirtualBox has the permission to create a new ﬁle in the directory. The ﬁnal command above deﬁnes that VirtualBox acts as a server, i.e. it creates the named pipe itself instead of connecting to an already existing one.

9.11 Fine-tuning the VirtualBox NAT engine
9.11.1 Conﬁguring the address of a NAT network interface
In NAT mode, the guest network interface is assigned to the IPv4 range 10.0.x.0/24 by default where x corresponds to the instance of the NAT interface +2. So x is 2 when there is only one

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NAT instance active. In that case the guest is assigned to the address 10.0.2.15, the gateway is set to 10.0.2.2 and the name server can be found at 10.0.2.3.
If, for any reason, the NAT network needs to be changed, this can be achieved with the following command:
VBoxManage modifyvm "VM name" --natnet1 "192.168/16"

This command would reserve the network addresses from 192.168.0.0 to 192.168.254.254 for the ﬁrst NAT network instance of “VM name”. The guest IP would be assigned to
192.168.0.15 and the default gateway could be found at 192.168.0.2.

9.11.2 Conﬁguring the boot server (next server) of a NAT network interface For network booting in NAT mode, by default VirtualBox uses a built-in TFTP server at the IP address 10.0.2.4. This default behavior should work ﬁne for typical remote-booting scenarios.
However, it is possible to change the boot server IP and the location of the boot image with the following commands:
VBoxManage modifyvm "VM name" --nattftpserver1 10.0.2.2
VBoxManage modifyvm "VM name" --nattftpfile1 /srv/tftp/boot/MyPXEBoot.pxe

9.11.3 Tuning TCP/IP buffers for NAT
The VirtualBox NAT stack performance is often determined by its interaction with the host’s
TCP/IP stack and the size of several buffers (SO_RCVBUF and SO_SNDBUF). For certain setups users might want to adjust the buffer size for a better performance. This can by achieved using the following commands (values are in kilobytes and can range from 8 to 1024):
VBoxManage modifyvm "VM name" --natsettings1 16000,128,128,0,0

This example illustrates tuning the NAT settings. The ﬁrst parameter is the MTU, then the size of the socket’s send buffer and the size of the socket’s receive buffer, the initial size of the TCP send window, and lastly the initial size of the TCP receive window. Note that specifying zero means fallback to the default value.
Each of these buffers has a default size of 64KB and default MTU is 1500.

9.11.4 Binding NAT sockets to a speciﬁc interface
By default, VirtualBox’s NAT engine will route TCP/IP packets through the default interface assigned by the host’s TCP/IP stack. (The technical reason for this is that the NAT engine uses sockets for communication.) If, for some reason, you want to change this behavior, you can tell the NAT engine to bind to a particular IP address instead. Use the following command:
VBoxManage modifyvm "VM name" --natbindip1 "10.45.0.2"

After this, all outgoing trafﬁc will be sent through the interface with the IP address 10.45.0.2.
Please make sure that this interface is up and running prior to this assignment.

9.11.5 Enabling DNS proxy in NAT mode
The NAT engine by default offers the same DNS servers to the guest that are conﬁgured on the host. In some scenarios, it can be desirable to hide the DNS server IPs from the guest, for example when this information can change on the host due to expiring DHCP leases. In this case, you can tell the NAT engine to act as DNS proxy using the following command:
VBoxManage modifyvm "VM name" --natdnsproxy1 on

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9.11.6 Using the host’s resolver as a DNS proxy in NAT mode
For resolving network names, the DHCP server of the NAT engine offers a list of registered
DNS servers of the host. If for some reason you need to hide this DNS server list and use the host’s resolver settings, thereby forcing the VirtualBox NAT engine to intercept DNS requests and forward them to host’s resolver, use the following command:
VBoxManage modifyvm "VM name" --natdnshostresolver1 on

Note that this setting is similar to the DNS proxy mode, however whereas the proxy mode just forwards DNS requests to the appropriate servers, the resolver mode will interpret the DNS requests and use the host’s DNS API to query the information and return it to the guest.
9.11.6.1 User-deﬁned host name resolving
In some cases it might be useful to intercept the name resolving mechanism, providing a userdeﬁned IP address on a particular DNS request. The intercepting mechanism allows the user to map not only a single host but domains and even more complex namings conventions if required.
The following command sets a rule for mapping a name to a speciﬁed IP:
VBoxManage setextradata "VM name" \
"VBoxInternal/Devices/{pcnet,e1000}/0/LUN#0/Config/HostResolverMappings/ \
<uniq name of interception rule>/HostIP" <IPv4>
VBoxManage setextradata "VM name" \
"VBoxInternal/Devices/{pcnet,e1000}/0/LUN#0/Config/HostResolverMappings/ \
<uniq name of interception rule>/HostName" <name of host>

The following command sets a rule for mapping a pattern name to a speciﬁed IP:
VBoxManage setextradata "VM name" \
"VBoxInternal/Devices/{pcnet,e1000}/0/LUN#0/Config/HostResolverMappings/ \
<uniq name of interception rule>/HostIP" <IPv4>
VBoxManage setextradata "VM name" \
"VBoxInternal/Devices/{pcnet,e1000}/0/LUN#0/Config/HostResolverMappings/ \
<uniq name of interception rule>/HostNamePattern" <hostpattern>

The host pattern may include "|", "?" and "*".
This example demonstrates how to instruct the host-resolver mechanism to resolve all domain and probably some mirrors of www.blocked-site.info site with IP 127.0.0.1:
VBoxManage setextradata "VM name" \
"VBoxInternal/Devices/e1000/0/LUN#0/Config/HostResolverMappings/ \ all_blocked_site/HostIP" 127.0.0.1
VBoxManage setextradata "VM name" \
"VBoxInternal/Devices/e1000/0/LUN#0/Config/HostResolverMappings/ \ all_blocked_site/HostNamePattern" "*.blocked-site.*|*.fb.org"

Note: The host resolver mechanism should be enabled to use user-deﬁned mapping rules (please see chapter 9.11.6, Using the host’s resolver as a DNS proxy in NAT mode, page 189 for more details).

9.11.7 Conﬁguring aliasing of the NAT engine
By default, the NAT core uses aliasing and uses random ports when generating an alias for a connection. This works well for the most protocols like SSH, FTP and so on. Though some protocols might need a more transparent behavior or may depend on the real port number the packet was sent from. It is possible to change the NAT mode via the VBoxManage frontend with the following commands:

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VBoxManage modifyvm "VM name" --nataliasmode1 proxyonly

and
VBoxManage modifyvm "Linux Guest" --nataliasmode1 sameports

The ﬁrst example disables aliasing and switches NAT into transparent mode, the second example enforces preserving of port values. These modes can be combined if necessary.

9.12 Conﬁguring the BIOS DMI information
The DMI data VirtualBox provides to guests can be changed for a speciﬁc VM. Use the following commands to conﬁgure the DMI BIOS information. In case your VM is conﬁgured to use EFI ﬁrmware you need to replace pcbios by efi in the keys.
DMI BIOS information (type 0)
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBIOSVendor"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBIOSVersion"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBIOSReleaseDate"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBIOSReleaseMajor"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBIOSReleaseMinor"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBIOSFirmwareMajor"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBIOSFirmwareMinor"

"BIOS Vendor"
"BIOS Version"
"BIOS Release Date"
1
2
3
4

DMI system information (type 1)
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiSystemVendor"
"System Vendor"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiSystemProduct"
"System Product"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiSystemVersion"
"System Version"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiSystemSerial"
"System Serial"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiSystemSKU"
"System SKU"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiSystemFamily"
"System Family"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiSystemUuid"
"9852bf98-b83c-49db-a8de-182c42c7226b"

DMI board information (type 2)
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBoardVendor"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBoardProduct"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBoardVersion"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBoardSerial"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBoardAssetTag"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBoardLocInChass"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiBoardBoardType"

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"Board Vendor"
"Board Product"
"Board Version"
"Board Serial"
"Board Tag"
"Board Location"
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DMI system enclosure or chassis (type 3)
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiChassisVendor"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiChassisType"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiChassisVersion"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiChassisSerial"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiChassisAssetTag"

"Chassis Vendor"
3
"Chassis Version"
"Chassis Serial"
"Chassis Tag"

DMI processor information (type 4)
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiProcManufacturer"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiProcVersion"

"GenuineIntel"
"Pentium(R) III"

DMI OEM strings (type 11)
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiOEMVBoxVer"
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiOEMVBoxRev"

"vboxVer_1.2.3"
"vboxRev_12345"

If a DMI string is not set, the default value of VirtualBox is used. To set an empty string use
"<EMPTY>".

Note that in the above list, all quoted parameters (DmiBIOSVendor, DmiBIOSVersion but not DmiBIOSReleaseMajor) are expected to be strings. If such a string is a valid number, the parameter is treated as number and the VM will most probably refuse to start with an
VERR_CFGM_NOT_STRING error. In that case, use "string:<value>", for instance
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/pcbios/0/Config/DmiSystemSerial"

"string:1234"

Changing this information can be necessary to provide the DMI information of the host to the guest to prevent Windows from asking for a new product key. On Linux hosts the DMI BIOS information can be obtained with dmidecode -t0

and the DMI system information can be obtained with dmidecode -t1

9.13 Conﬁguring the custom ACPI table
VirtualBox can be conﬁgured to present an custom ACPI table to the guest. Use the following command to conﬁgure this:
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/acpi/0/Config/CustomTable" "/path/to/table.bin"

Conﬁguring a custom ACPI table can prevent Windows Vista and Windows 7 from asking for a new product key. On Linux hosts, one of the host tables can be read from
/sys/ﬁrmware/acpi/tables/.

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9.14 Fine-tuning timers and time synchronization
9.14.1 Conﬁguring the guest time stamp counter (TSC) to reﬂect guest execution By default, VirtualBox keeps all sources of time visible to the guest synchronized to a single time source, the monotonic host time. This reﬂects the assumptions of many guest operating systems, which expect all time sources to reﬂect “wall clock” time. In special circumstances it may be useful however to make the TSC (time stamp counter) in the guest reﬂect the time actually spent executing the guest.
This special TSC handling mode can be enabled on a per-VM basis, and for best results must be used only in combination with hardware virtualization. To enable this mode use the following command: VBoxManage setextradata "VM name" "VBoxInternal/TM/TSCTiedToExecution" 1

To revert to the default TSC handling mode use:
VBoxManage setextradata "VM name" "VBoxInternal/TM/TSCTiedToExecution"

Note that if you use the special TSC handling mode with a guest operating system which is very strict about the consistency of time sources you may get a warning or error message about the timing inconsistency. It may also cause clocks to become unreliable with some guest operating systems depending on how they use the TSC.

9.14.2 Accelerate or slow down the guest clock
For certain purposes it can be useful to accelerate or to slow down the (virtual) guest clock. This can be achieved as follows:
VBoxManage setextradata "VM name" "VBoxInternal/TM/WarpDrivePercentage" 200

The above example will double the speed of the guest clock while
VBoxManage setextradata "VM name" "VBoxInternal/TM/WarpDrivePercentage" 50

will halve the speed of the guest clock. Note that changing the rate of the virtual clock can confuse the guest and can even lead to abnormal guest behavior. For instance, a higher clock rate means shorter timeouts for virtual devices with the result that a slightly increased response time of a virtual device due to an increased host load can cause guest failures. Note further that any time synchronization mechanism will frequently try to resynchronize the guest clock with the reference clock (which is the host clock if the VirtualBox Guest Additions are active).
Therefore any time synchronization should be disabled if the rate of the guest clock is changed as described above (see chapter 9.14.3, Tuning the Guest Additions time synchronization parameters, page 192).

9.14.3 Tuning the Guest Additions time synchronization parameters
The VirtualBox Guest Additions ensure that the guest’s system time is synchronized with the host time. There are several parameters which can be tuned. The parameters can be set for a speciﬁc
VM using the following command:
VBoxManage guestproperty set "VM name" "/VirtualBox/GuestAdd/VBoxService/PARAMETER" VALUE

where PARAMETER is one of the following:
--timesync-interval Speciﬁes the interval at which to synchronize the time with the host.

The default is 10000 ms (10 seconds).

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9 Advanced topics
--timesync-min-adjust The minimum absolute drift value measured in milliseconds to make

adjustments for. The default is 1000 ms on OS/2 and 100 ms elsewhere.
--timesync-latency-factor The factor to multiply the time query latency with to calculate

the dynamic minimum adjust time. The default is 8 times, that means in detail: Measure the time it takes to determine the host time (the guest has to contact the VM host service which may take some time), multiply this value by 8 and do an adjustment only if the time difference between host and guest is bigger than this value. Don’t do any time adjustment otherwise. --timesync-max-latency The max host timer query latency to accept. The default is 250 ms.
--timesync-set-threshold The absolute drift threshold, given as milliseconds where to start

setting the time instead of trying to smoothly adjust it. The default is 20 minutes.
--timesync-set-start Set the time when starting the time sync service.
--timesync-set-on-restore 0|1 Set the time after the VM was restored from a saved state

when passing 1 as parameter (default). Disable by passing 0. In the latter case, the time will be adjusted smoothly which can take a long time.
All these parameters can be speciﬁed as command line parameters to VBoxService as well.

9.14.4 Disabling the Guest Additions time synchronization
Once installed and started, the VirtualBox Guest Additions will try to synchronize the guest time with the host time. This can be prevented by forbidding the guest service from reading the host clock: VBoxManage setextradata "VM name" "VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled" 1

9.15 Installing the alternate bridged networking driver on
Solaris 11 hosts
Starting with VirtualBox 4.1, VirtualBox ships a new network ﬁlter driver that utilizes Solaris
11’s Crossbow functionality. By default, this new driver is installed for Solaris 11 hosts (builds
159 and above) that has support for it.
To force installation of the older STREAMS based network ﬁlter driver, execute as root the following command before installing the VirtualBox package: touch /etc/vboxinst_vboxflt

To force installation of the Crossbow based network ﬁlter driver, execute as root the following command before installing the VirtualBox package: touch /etc/vboxinst_vboxbow

To check which driver is currently being used by VirtualBox, execute: modinfo | grep vbox

If the output contains “vboxbow”, it indicates VirtualBox is using the Crossbow network ﬁlter driver, while the name “vboxﬂt” indicates usage of the older STREAMS network ﬁlter.

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9.16 VirtualBox VNIC templates for VLANs on Solaris 11 hosts VirtualBox supports VNIC (Virtual Network Interface) templates for conﬁguring VMs over
VLANs.3 A VirtualBox VNIC template is a VNIC whose name starts with “vboxvnic_template”
(case-sensitive).
On Solaris 11 hosts4 , a VNIC template may be used to specify the VLAN ID to use while bridging over a network link.
Here is an example of how to use a VNIC template to conﬁgure a VM over a VLAN. Create a
VirtualBox VNIC template, by executing as root: dladm create-vnic -t -l nge0 -v 23 vboxvnic_template0

This will create a temporary VNIC template over interface “nge0” with the VLAN ID 23. To create VNIC templates that are persistent across host reboots, skip the -t parameter in the above command. You may check the current state of links using:
$ dladm show-link
LINK
CLASS
MTU
nge0 phys 1500 nge1 phys
1500
vboxvnic_template0 vnic 1500
$ dladm show-vnic
LINK
OVER vboxvnic_template0 nge0

STATE up down up SPEED
1000

BRIDGE
----

OVER
--nge0

MACADDRESS
2:8:20:25:12:75

MACADDRTYPE random VID
23

Once the VNIC template is created, any VMs that need to be on VLAN 23 over the interface
“nge0” can be conﬁgured to bridge using this VNIC template.
VNIC templates makes managing VMs on VLANs simpler and efﬁcient. The VLAN details are not stored as part of every VM’s conﬁguration but rather inherited from the VNIC template while starting the VM. The VNIC template itself can be modiﬁed anytime using dladm.
VNIC templates can be created with additional properties such as bandwidth limits, CPU fanout etc. Refer to your Solaris network documentation on how to accomplish this. These additional properties, if any, are also applied to VMs which bridge using the VNIC template.

9.17 Conﬁguring multiple host-only network interfaces on
Solaris hosts
By default VirtualBox provides you with one host-only network interface. Adding more host-only network interfaces on Solaris hosts requires manual conﬁguration. Here’s how to add another host-only network interface.
Begin by stopping all running VMs. Then, unplumb the existing “vboxnet0” interface by execute the following command as root: ifconfig vboxnet0 unplumb

If you have several vboxnet interfaces, you will need to unplumb all of them. Once all vboxnet interfaces are unplumbed, remove the driver by executing the following command as root: rem_drv vboxnet

Edit the ﬁle /platform/i86pc/kernel/drv/vboxnet.conf and add a line for the new interface we want to add as shown below:
3 Support

for Crossbow based bridged networking was introduced with VirtualBox 4.1 and requires Solaris 11 build 159 or above.
4 When Crossbow based bridged networking is used.

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9 Advanced topics name="vboxnet" parent="pseudo" instance=1; name="vboxnet" parent="pseudo" instance=2;

Add as many of these lines as required with each line having a unique instance number.
Next, reload the vboxnet driver by executing the following command as root: add_drv vboxnet

On Solaris 11.1 and newer hosts you may want to rename the default vanity interface name.
To check what name has been assigned, execute: dladm show-phys
LINK
net0 net2 net1

MEDIA
Ethernet
Ethernet
Ethernet

STATE up up up SPEED
100
1000
1000

DUPLEX full full full DEVICE e1000g0 vboxnet1 vboxnet0 In the above example, we can rename “net2” to “vboxnet1” before proceeding to plumb the interface. This can be done by executing as root: dladm rename-link net2 vboxnet1

Now plumb all the interfaces using ifconfig vboxnetX plumb (where ’X’ would be 1 in this case). Once the interface is plumbed, it may be conﬁgured like any other network interface.
Refer to the ifconfig documentation for further details.
To make the newly added interfaces’ settings persistent across reboots, you will need to edit the ﬁles /etc/inet/netmasks, and if you are using NWAM /etc/nwam/llp and add the appropriate entries to set the netmask and static IP for each of those interfaces. The VirtualBox installer only updates these conﬁguration ﬁles for the one “vboxnet0” interface it creates by default.

9.18 Conﬁguring the VirtualBox CoreDumper on Solaris hosts VirtualBox is capable of producing its own core ﬁles for extensive debugging when things go wrong. Currently this is only available on Solaris hosts.
The VirtualBox CoreDumper can be enabled using the following command:
VBoxManage setextradata "VM name" VBoxInternal2/CoreDumpEnabled 1

You can specify which directory to use for core dumps with this command:
VBoxManage setextradata "VM name" VBoxInternal2/CoreDumpDir <path-to-directory>

Make sure the directory you specify is on a volume with sufﬁcient free space and that the
VirtualBox process has sufﬁcient permissions to write ﬁles to this directory. If you skip this command and don’t specify any core dump directory, the current directory of the VirtualBox executable will be used (which would most likely fail when writing cores as they are protected with root permissions). It is recommended you explicitly set a core dump directory.
You must specify when the VirtualBox CoreDumper should be triggered. This is done using the following commands:
VBoxManage setextradata "VM name" VBoxInternal2/CoreDumpReplaceSystemDump 1
VBoxManage setextradata "VM name" VBoxInternal2/CoreDumpLive 1

At least one of the above two commands will have to be provided if you have enabled the
VirtualBox CoreDumper.

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Setting CoreDumpReplaceSystemDump sets up the VM to override the host’s core dumping mechanism and in the event of any crash only the VirtualBox CoreDumper would produce the core ﬁle.
Setting CoreDumpLive sets up the VM to produce cores whenever the VM process receives a
SIGUSR2 signal. After producing the core ﬁle, the VM will not be terminated and will continue to run. You can thus take cores of the VM process using: kill -s SIGUSR2 <VM-process-id>

Core ﬁles produced by the VirtualBox CoreDumper are of the form core.vb.<ProcessName>.<ProcessID>, for example core.vb.VBoxHeadless.11321.

9.19 VirtualBox and Solaris kernel zones
Solaris kernel zones on x86-based systems make use of hardware-assisted virtualization features like VirtualBox does. However, for kernel zones and VirtualBox to share this hardware resource, they need to co-operate.
By default, due to performance reasons, VirtualBox acquires the hardware-assisted virtualization resource (VT-x/AMD-V) globally on the host machine and uses it until the last VirtualBox
VM that requires it is powered off. This prevents other software from using VT-x/AMD-V during the time VirtualBox has taken control of it.
VirtualBox can be instructed to relinquish use of hardware-assisted virtualization features when not executing guest code, thereby allowing kernel zones to make use of them. To do this, shutdown all VirtualBox VMs and execute the following command:
VBoxManage setproperty hwvirtexclusive off

This command needs to be executed only once as the setting is stored as part of the global
VirtualBox settings which will continue to persist across host-reboots and VirtualBox upgrades.

9.20 Locking down the VirtualBox manager GUI
9.20.1 Customizing the VM manager
There are several advanced customization settings for locking down the VirtualBox manager, that is, removing some features that the user should not see.
VBoxManage setextradata global GUI/Customizations OPTION[,OPTION...]

where OPTION is one of the following keywords: noSelector Don’t allow to start the VirtualBox manager. Trying to do so will show a window

containing a proper error message. noMenuBar VM windows will not contain a menu bar. noStatusBar VM windows will not contain a status bar.

To disable any of these VM manager customizations do
VBoxManage setextradata global GUI/Customizations

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9.20.2 VM selector customization
The following per-machine VM extradata settings can be used to change the behavior of the VM selector window in respect of certain VMs:
VBoxManage setextradata "VM name" true

where SETTING can be:
GUI/HideDetails Don’t show the VM conﬁguration of a certain VM. The details window will

remain just empty if this VM is selected.
GUI/PreventReconfiguration Don’t allow the user to open the settings dialog for a certain

VM.
GUI/PreventSnapshotOperations Prevent snapshot operations for a VM from the GUI, either

at runtime or when the VM is powered off.
GUI/HideFromManager Hide a certain VM in the VM selector window.
GUI/PreventApplicationUpdate Disable the automatic update check and hide the corre-

sponding menu item.
Please note that these settings wouldn’t prevent the user from reconﬁguring the VM by
VBoxManage modifyvm.

9.20.3 Conﬁgure VM selector menu entries
You can disable (i.e. black-list) certain entries in the global settings page of the VM selector:
VBoxManage setextradata global GUI/RestrictedGlobalSettingsPages OPTION[,OPTION...]

where OPTION is one of the following keywords:
General Don’t show the General settings pane.
Input Don’t show the Input settings pane.
Update Don’t show the Update settings pane.
Language Don’t show the Language settings pane.
Display Don’t show the Display settings pane.
Network Don’t show the Network settings pane.
Extensions Don’t show the Extensions settings pane.
Proxy Don’t show the Proxy settings pane.

This is a global setting. Any combination of the above is allowed. To restore the default behavior, use
VBoxManage setextradata global GUI/RestrictedGlobalSettingsPages

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9.20.4 Conﬁgure VM window menu entries
You can disable (i.e. black-list) certain menu actions in the VM window:
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeMenus OPTION[,OPTION...]

where OPTION is one of the following keywords:
All Don’t show any menu in the VM window.
Machine Don’t show the Machine menu in the VM window.
View Don’t show the View menu in the VM window.
Devices Don’t show the Devices menu in the VM window.
Help Don’t show the Help menu in the VM window.
Debug Don’t show the Debug menu in the VM window. The debug menu is only visible if the GUI

was started with special command line parameters or environment variable settings.
This is a per-VM setting. Any combination of the above is allowed. To restore the default behavior, use
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeMenus

You can also disable (i.e. blacklist) certain menu actions of certain menus. Use the following command to disable certain actions of the Application menu (only available on Mac OS X hosts):
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeApplicationMenuActions OPTION[,OPTION...]

where OPTION is one of the following keywords:
All Don’t show any menu item in this menu.
About Don’t show the About menu item in this menu.

This is a per-VM setting. Any combination of the above is allowed. To restore the default behavior, use
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeMenus

Use the following command to disable certain actions of the Machine menu:
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeApplicationMenuActions OPTION[,OPTION...]

where OPTION is one of the following keywords:
All Don’t show any menu item in this menu.
SettingsDialog Don’t show the Settings menu item in this menu.
TakeSnapshot Don’t show the Take Snapshot menu item in this menu.
TakeScreenshot Don’t show the Take Screenshot menu item in this menu.
InformationDialog Don’t show the Session Information menu item in this menu.
MouseIntegration Don’t show the Disable Mouse Integration menu item in this menu.
TypeCAD Don’t show the Insert Ctrl+Alt+Del menu item in this menu.

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TypeCABS Don’t show the Insert Ctrl+Alt+Backspace menu item in this menu (available on X11

hosts only).
Pause Don’t show the Pause menu item in this menu.
Reset Don’t show the Reset menu item in this menu.
SaveState Don’t show the Save the machine state menu item in this menu.
Shutdown Don’t show the ACPI Shutdown menu item in this menu.
PowerOff Don’t show the Power Off the machine menu item in this menu.

This is a per-VM setting. Any combination of the above is allowed. To restore the default behavior, use
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeApplicationMenuActions

Use the following command to disable certain actions of the View menu:
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeViewMenuActions OPTION[,OPTION...]

where OPTION is one of the following keywords:
All Don’t show any menu item in this menu.
Fullscreen Don’t show the Switch to Fullscreen menu item in this menu.
Seamless Don’t show the Switch to Seamless Mode menu item in this menu.
Scale Don’t show the Switch to Scaled Mode menu item in this menu.
GuestAutoresize Don’t show the Auto-resize Guest Display menu item in this menu.
AdjustWindow Don’t show the Adjust Window Size menu item in this menu.
Multiscreen Don’t show the Multiscreen menu item in this menu (only visible in full screen /

seamless mode).
This is a per-VM setting. Any combination of the above is allowed. To restore the default behavior, use
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeViewMenuActions

Use the following command to disable certain actions of the View menu:
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeDevicesMenuActions OPTION[,OPTION...]

where OPTION is one of the following keywords to disable actions in the Devices menu:
All Don’t show any menu item in this menu.
OpticalDevices Don’t show the CD/DVD Devices menu item in this menu.
FloppyDevices Don’t show the FLoppy Devices menu item in this menu.
USBDevices Don’t show the USB Devices menu item in this menu.
SharedClipboard Don’t show the Shared Clipboard menu item in this menu.
DragAndDrop Don’t show the Drag’n’Drop menu item in this menu.
NetworkSettings Don’t show the Network Settings... menu item in this menu.

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SharedFoldersSettings Don’t show the Shared Folders Settings... menu item in this menu.
VRDEServer Don’t show the Remove Display menu item in this menu.
InstallGuestTools Don’t show the Insert Guest Additions CD imnage... menu item in this

menu.
This is a per-VM setting. Any combination of the above is allowed. To restore the default behavior, use
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeDevicesMenuActions

Use the following command to disable certain actions of the View menu:
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeDebuggerMenuActions OPTION[,OPTION...]

where OPTION is one of the following keywords to disable actions in the Debug menu (normally completely disabled):
All Don’t show any menu item in this menu.
Statistics Don’t show the Statistics... menu item in this menu.
CommandLine Don’t show the Command Line... menu item in this menu.
Logging Don’t show the Logging... menu item in this menu.
LogDialog Don’t show the Show Log... menu item in this menu.

This is a per-VM setting. Any combination of the above is allowed. To restore the default behavior, use
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeDebuggerMenuActions

Use the following command to disable certain actions of the View menu:
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeHelpMenuActions OPTION[,OPTION...]

where OPTION is one of the following keywords to disable actions in the Help menu (normally completely disabled):
All Don’t show any menu item in this menu.
Contents Don’t show the Contents... menu item in this menu.
WebSite Don’t show the VirtualBox Web Site... menu item in this menu.
ResetWarnings Don’t show the Reset All Warnings menu item in this menu.
NetworkAccessManager Don’t show the Network Operations Manager menu item in this menu.
About Don’t show the About menu item in this menu (only on non Mac OS X hosts).
Contents Don’t show the Contents... menu item in this menu.
Contents Don’t show the Contents... menu item in this menu.

This is a per-VM setting. Any combination of the above is allowed. To restore the default behavior, use
VBoxManage setextradata "VM name" GUI/RestrictedRuntimeHelpMenuActions

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9.20.5 Conﬁgure VM window status bar entries
You can disable (i.e. black-list) certain status bar items:
VBoxManage setextradata "VM name" GUI/RestrictedStatusBarIndicators OPTION[,OPTION...]

where OPTION is one of the following keywords:
HardDisks Don’t show the hard disk icon in the VM window status bar. By default the hard disk

icon is only shown if the VM conﬁguration contains one or more hard disks.
OpticalDisks Don’t show the CD icon in the VM window status bar. By default the CD icon is

only shown if the VM conﬁguration contains one or more CD drives.
FloppyDisks Don’t show the ﬂoppy icon in the VM window status bar. By default the ﬂoppy

icon is only shown if the VM conﬁguration contains one more more ﬂoppy drives.
Network Don’t show the network icon in the VM window status bar. By default the network icon

is only shown if the VM conﬁguration contains one or more active network adapters.
USB Don’t show the USB icon in the status bar.
SharedFolders Don’t show the shared folders icon in the status bar.
VideoCapture Don’t show the video capture icon in the status bar.
Features Don’t show the CPU features icon in the status bar.
Mouse Don’t show the mouse icon in the status bar.
Keyboard Don’t show the keyboard icon in the status bar.

This is a per-VM setting. Any combination of the above is allowed. If all options are speciﬁed, no icons are displayed in the status bar of the VM window. To restore the default behavior, use
VBoxManage setextradata "VM name" GUI/RestrictedStatusBarIndicators

9.20.6 Conﬁgure VM window visual modes
You can disable (i.e. black-list) certain VM visual modes:
VBoxManage setextradata "VM name" GUI/RestrictedVisualStates OPTION[,OPTION...]

where OPTION is one of the following keywords:
Fullscreen Don’t allow to switch the VM into full screen mode.
Seamless Don’t allow to switch the VM into seamless mode.
Scale Don’t allow to switch the VM into scale mode.

This is a per-VM setting. Any combination of the above is allowed. To restore the default behavior, use
VBoxManage setextradata "VM name" GUI/RestrictedVisualStates

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9.20.7 Host Key customization
To disable all host key combinations, open the preferences and change the host key to None. This might be useful when using VirtualBox in a kiosk mode.
To redeﬁne or disable certain host key actions, use the following command:
VBoxManage setextradata global GUI/Input/MachineShortcuts "FullscreenMode=F,...."

The following list shows the possible host key actions together with their default host key shortcut. Setting an action to None will disable that host key action.
Action
TakeSnapshot
TakeScreenshot
MouseIntegration
TypeCAD
TypeCABS
Pause
Reset
SaveState
Shutdown
PowerOff
Close
FullscreenMode
SeamlessMode
ScaleMode
GuestAutoResize
WindowAdjust
PopupMenu
SettingsDialog
InformationDialog
NetworkAdaptersDialog
SharedFoldersDialog
InstallGuestAdditions

Default Key
T
E
I
Del
Backspace
P
R
H
Q
F
L
C
G
A
Home
S
N

D

Action take a snapshot take a screenshot toggle mouse integration inject Ctrl+Alt+Del inject Ctrl+Alt+Backspace
Pause the VM
(hard) reset the guest save the VM state and terminate the VM press the (virtual) ACPI power button power the VM off (without saving the state!) show the VM close dialog switch the VM into full screen switch the VM into seamless mode switch the VM into scale mode automatically resize the guest window immediately resize the guest window show popup menu in full screen / seaml. mode open the VM settings dialog show the VM information window show the VM network adapters dialog show the VM shared folders dialog mount the ISO containing the Guest Additions

To disable the full screen mode as well as the seamless mode, use the following command:
VBoxManage setextradata global GUI/Input/MachineShortcuts "FullscreenMode=None,SeamlessMode=None"

9.20.8 Action when terminating the VM
You can disallow (i.e. black-list) certain actions when terminating a VM. To disallow speciﬁc actions, type:
VBoxManage setextradata "VM name" GUI/RestrictedCloseActions OPTION[,OPTION...]

where OPTION is one of the following keywords:
SaveState Don’t allow the user to save the VM state when terminating the VM.
Shutdown Don’t allow the user to shutdown the VM by sending the ACPI power-off event to the

guest.
PowerOff Don’t allow the user to power off the VM.
PowerOffRestoringSnapshot Don’t allow the user to return to the last snapshot when power-

ing off the VM.
This is a per-VM setting. Any combination of the above is allowed. If all options are speciﬁed, the VM cannot be shut down at all.

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9.20.9 Action for handling a Guru Meditation
A VM runs into a Guru Meditation if there is a problem which cannot be ﬁxed by other means than terminating the process. The default is to show a message window which instructs the user to open a bug report.
This behavior can be conﬁgured:
VBoxManage setextradata "VM name" GUI/GuruMeditationHandler MODE

where MODE is one of the following keywords:
Default A message window is shown. After the user conﬁrmed, the VM is terminated.
PowerOff The VM is immediately powered-off without showing any message window. The VM

logﬁle will show information about what happend.
Ignore The VM is left in stuck mode. Execution is stopped but no message window is shown.

The VM has to be powered off manually.
This is a per-VM setting.

9.20.10 Conﬁguring automatic mouse capturing
By default, the mouse is captured if the user clicks on the guest window and the guest expects relative mouse coordiantes at this time. This happens if the pointing device is conﬁgured as PS/2 mouse and the guest did not (yet) start the VirtualBox Guest Additions (for instance, the guest is booting or no Guest Additions installed at all) or if the pointing device is conﬁgured as USB tablet but the guest has no USB driver loaded yet. Once the Guest Additions become active or the USB guest driver is started, the mouse capture is automatically released.
The default behavior is sometimes not desired. Therefore it can be conﬁgured:
VBoxManage setextradata "VM name" GUI/MouseCapturePolicy MODE

where MODE is one of the following keywords:
Default The default behavior as described above.
HostComboOnly The mouse is only captured if the Host Key is toggled.
Disabled The mouse is never captured, also not by toggling the Host Key

This is a per-VM setting.

9.20.11 Conﬁguring automatic mouse capturing
By default, the mouse is captured if the user clicks on the guest window and the guest expects relative mouse coordiantes at this time. This happens if the pointing device is conﬁgured as PS/2 mouse and the guest did not (yet) start the VirtualBox Guest Additions (for instance, the guest is booting or no Guest Additions installed at all) or if the pointing device is conﬁgured as USB tablet but the guest has no USB driver loaded yet. Once the Guest Additions become active or the USB guest driver is started, the mouse capture is automatically released.
The default behavior is sometimes not desired. Therefore it can be conﬁgured:
VBoxManage setextradata "VM name" GUI/MouseCapturePolicy MODE

where MODE is one of the following keywords:
Default The default behavior as described above.
HostComboOnly The mouse is only captured if the Host Key is toggled.
Disabled The mouse is never captured, also not by toggling the Host Key

This is a per-VM setting.

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9.20.12 Requesting legacy full-screen mode
As of version 4.3.16, VirtualBox uses special window manager facilities to switch a multi-screen machine to full-screen on a multi-monitor host system. However, not all window managers provide these facilities correctly, so VirtualBox can be told to use the old method of switching to full-screen mode instead using the command:
VBoxManage setextradata global GUI/Fullscreen/LegacyMode true

You can go back to the new method using the command:
VBoxManage setextradata global GUI/Fullscreen/LegacyMode

This is a global setting.

9.21 Starting the VirtualBox web service automatically
The VirtualBox web service (vboxwebsrv) is used for controlling VirtualBox remotely. It is documented in detail in the VirtualBox Software Development Kit (SDK); please see chapter 11,
VirtualBox programming interfaces, page 225. As the client base using this interface is growing, we added start scripts for the various operation systems we support. The following sections describe how to use them. The VirtualBox web service is never started automatically as a result of a standard installation.

9.21.1 Linux: starting the webservice via init
On Linux, the web service can be automatically started during host boot by adding appropriate parameters to the ﬁle /etc/default/virtualbox. There is one mandatory parameter,
VBOXWEB_USER, which must be set to the user which will later start the VMs. The parameters in the table below all start with VBOXWEB_ (VBOXWEB_HOST, VBOXWEB_PORT etc.):
Parameter
USER
HOST
PORT
SSL_KEYFILE
SSL_PASSWORDFILE
SSL_CACERT
SSL_CAPATH
SSL_DHFILE
SSL_RANDFILE
TIMEOUT
CHECK_INTERVAL
THREADS
KEEPALIVE
ROTATE
LOGSIZE
LOGINTERVAL

Description
The user as which the web service runs
The host to bind the web service to
The port to bind the web service to
Server key and certiﬁcate ﬁle, PEM format
File name for password to server key
CA certiﬁcate ﬁle, PEM format
CA certiﬁcate path
DH ﬁle name or DH key length in bits
File containing seed for random number generator
Session timeout in seconds; 0 disables timeouts
Frequency of timeout checks in seconds
Maximum number of worker threads to run in parallel
Maximum number of requests before a socket will be closed Number of log ﬁles; 0 disables log rotation
Maximum size of a log ﬁle in bytes to trigger rotation
Maximum time interval in seconds to trigger log rotation

Default localhost 18083

300
5
100
100
10
1MB
1 day

Setting the parameter SSL_KEYFILE enables the SSL/TLS support. Using encryption is strongly encouraged, as otherwise everything (including passwords) is transferred in clear text.

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9.21.2 Solaris: starting the web service via SMF
On Solaris hosts, the VirtualBox web service daemon is integrated into the SMF framework. You can change the parameters, but don’t have to if the defaults below already match your needs: svccfg -s svc:/application/virtualbox/webservice:default setprop config/host=localhost svccfg -s svc:/application/virtualbox/webservice:default setprop config/port=18083 svccfg -s svc:/application/virtualbox/webservice:default setprop config/user=root

The table in the previous section showing the parameter names and defaults also applies to
Solaris. The parameter names must be changed to lowercase and a preﬁx of config/ has to be added, e.g. config/user or config/ssl_keyfile. If you made any change, don’t forget to run the following command to put the changes into effect immediately: svcadm refresh svc:/application/virtualbox/webservice:default

If you forget the above command then the previous settings will be used when enabling the service. Check the current property settings with: svcprop -p config svc:/application/virtualbox/webservice:default

When everything is conﬁgured correctly you can start the VirtualBox web service with the following command: svcadm enable svc:/application/virtualbox/webservice:default

For more information about SMF, please refer to the Solaris documentation.

9.21.3 Mac OS X: starting the webservice via launchd
On Mac OS X, launchd is used to start the VirtualBox webservice. An example conﬁguration ﬁle can be found in $HOME/Library/LaunchAgents/org.virtualbox.vboxwebsrv.plist. It can be enabled by changing the Disabled key from true to false. To manually start the service use the following command: launchctl load ~/Library/LaunchAgents/org.virtualbox.vboxwebsrv.plist

For additional information on how launchd services could be conﬁgured see http:// developer.apple.com/mac/library/documentation/MacOSX/Conceptual/BPSystemStartup/ BPSystemStartup.html.

9.22 VirtualBox Watchdog
Starting with VirtualBox 4.2 the memory ballooning service formerly known as VBoxBalloonCtrl was renamed to VBoxWatchdog, which now incorporates several host services that are meant to be run in a server environment.
These services are:
• Memory ballooning control, which automatically takes care of a VM’s conﬁgured memory balloon (see chapter 4.9.1, Memory ballooning, page 78 for an introduction to memory ballooning). This especially is useful for server environments where VMs may dynamically require more or less memory during runtime.
The service periodically checks a VM’s current memory balloon and its free guest RAM and automatically adjusts the current memory balloon by inﬂating or deﬂating it accordingly.
This handling only applies to running VMs having recent Guest Additions installed.

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• Host isolation detection, which provides a way to detect whether the host cannot reach the speciﬁc VirtualBox server instance anymore and take appropriate actions, such as shutting down, saving the current state or even powering down certain VMs.
All conﬁguration values can be either speciﬁed via command line or global extradata, whereas command line values always have a higher priority when set. Some of the conﬁguration values also be be speciﬁed on a per-VM basis. So the overall lookup order is: command line, per-VM basis extradata (if available), global extradata.

9.22.1 Memory ballooning control
The memory ballooning control inﬂates and deﬂates the memory balloon of VMs based on the
VMs free memory and the desired maximum balloon size.
To set up the memory ballooning control the maximum ballooning size a VM can reach needs to be set. This can be speciﬁed via command line with
--balloon-max <Size in MB>

, on a per-VM basis extradata value with
VBoxManage setextradata <VM-Name> VBoxInternal2/Watchdog/BalloonCtrl/BalloonSizeMax <Size in MB>

or using a global extradata value with
VBoxManage setextradata global VBoxInternal2/Watchdog/BalloonCtrl/BalloonSizeMax <Size in MB>

Note: If no maximum ballooning size is speciﬁed by at least one of the parameters above, no ballooning will be performed at all.
Setting the ballooning increment in MB can be either done via command line with
--balloon-inc <Size in MB>

or using a global extradata value with
VBoxManage setextradata global VBoxInternal2/Watchdog/BalloonCtrl/BalloonIncrementMB <Size in MB>

Default ballooning increment is 256 MB if not speciﬁed.
Same goes with the ballooning decrement: Via command line with
--balloon-dec <Size in MB>

or using a global extradata value with
VBoxManage setextradata global VBoxInternal2/Watchdog/BalloonCtrl/BalloonDecrementMB <Size in MB>

Default ballooning decrement is 128 MB if not speciﬁed.
To deﬁne the lower limit in MB a balloon can be the command line with
--balloon-lower-limit <Size in MB>

can be used or using a global extradata value with
VBoxManage setextradata global VBoxInternal2/Watchdog/BalloonCtrl/BalloonLowerLimitMB <Size in MB>

is available. Default lower limit is 128 if not speciﬁed.

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9.22.2 Host isolation detection
To detect whether a host is being isolated, that is, the host cannot reach the VirtualBox server instance anymore, the host needs to set an alternating value to a global extradata value within a time period. If this value is not set within that time period a timeout occurred and the so-called host isolation response will be performed to the VMs handled. Which VMs are handled can be controlled by deﬁning VM groups and assigning VMs to those groups. By default no groups are set, meaning that all VMs on the server will be handled when no host response is received within
30 seconds.
To set the groups handled by the host isolation detection via command line:
--apimon-groups=<string[,stringN]>

or using a global extradata value with
VBoxManage setextradata global VBoxInternal2/Watchdog/APIMonitor/Groups <string[,stringN]>

To set the host isolation timeout via command line:
--apimon-isln-timeout=<ms>

or using a global extradata value with
VBoxManage setextradata global VBoxInternal2/Watchdog/APIMonitor/IsolationTimeoutMS <ms>

To set the actual host isolation response via command line:
--apimon-isln-response=<cmd>

or using a global extradata value with
VBoxManage setextradata global VBoxInternal2/Watchdog/APIMonitor/IsolationResponse <cmd>

The following response commands are available:
• none, which does nothing.
• pause, which pauses the execution of a VM.
• poweroff, which shuts down the VM by pressing the virtual power button. The VM will not have the chance of saving any data or veto the shutdown process.
• save, which saves the current machine state and powers off the VM afterwards. If saving the machine state fails the VM will be paused.
• shutdown, which shuts down the VM in a gentle way by sending an ACPI shutdown event to the VM’s operating system. The OS then has the chance of doing a clean shutdown.

9.22.3 More information
For more advanced options and parameters like verbose logging check the built-in command line help accessible with --help.

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9.22.4 Linux: starting the watchdog service via init
On Linux, the watchdog service can be automatically started during host boot by adding appropriate parameters to the ﬁle /etc/default/virtualbox. There is one mandatory parameter,
VBOXWATCHDOG_USER, which must be set to the user which will later start the VMs. For backward compatibility you can also specify VBOXBALLOONCTRL_USERThe parameters in the table below all start with VBOXWATCHDOG_ (VBOXWATCHDOG_BALLOON_INTERVAL, VBOXWATCHDOG_LOGSIZE etc., and for previously existing parameters the VBOXBALLOONCTRL_INTERVAL etc. parameters can still be used):
Parameter

Description

Default

USER
ROTATE
LOGSIZE
LOGINTERVAL
BALLOON_INTERVAL
BALLOON_INCREMENT
BALLOON_DECREMENT
BALLOON_LOWERLIMIT
BALLOON_SAFETYMARGIN

The user as which the watchdog service runs
Number of log ﬁles; 0 disables log rotation
Maximum size of a log ﬁle in bytes to trigger rotation
Maximum time interval in seconds to trigger log rotation
Interval for checking the balloon size (msec)
Balloon size increment (MByte)
Balloon size decrement (MByte)
Balloon size lower limit (MByte)
Free memory required for decreasing the balloon size
(MByte)

10
1MB
1 day
30000
256
128
64
1024

9.22.5 Solaris: starting the watchdog service via SMF
On Solaris hosts, the VirtualBox watchdog service daemon is integrated into the SMF framework.
You can change the parameters, but don’t have to if the defaults already match your needs: svccfg -s svc:/application/virtualbox/balloonctrl:default setprop config/balloon_interval=10000 svccfg -s svc:/application/virtualbox/balloonctrl:default setprop config/balloon_safetymargin=134217728

The table in the previous section showing the parameter names and defaults also applies to
Solaris. The parameter names must be changed to lowercase and a preﬁx of config/ has to be added, e.g. config/user or config/balloon_safetymargin. If you made any change, don’t forget to run the following command to put the changes into effect immediately: svcadm refresh svc:/application/virtualbox/balloonctrl:default

If you forget the above command then the previous settings will be used when enabling the service. Check the current property settings with: svcprop -p config svc:/application/virtualbox/balloonctrl:default

When everything is conﬁgured correctly you can start the VirtualBox watchdog service with the following command: svcadm enable svc:/application/virtualbox/balloonctrl:default

For more information about SMF, please refer to the Solaris documentation.

9.23 Other extension packs
Starting with VirtualBox 4.2.0 there is another extension pack, VNC, which is open source and replaces the previous integration of the VNC remote access protocol. This is experimental code, and will be initially available in the VirtualBox source code package only. It is to a large portion code contributed by users, and is not supported in any way by Oracle.

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The keyboard handling is severely limited, and only the US keyboard layout works. Other keyboard layouts will have at least some keys which produce the wrong results (often quite surprising effects), and for layouts which have signiﬁcant differences to the US keyboard layout it is most likely unusable.
It is possible to install both the Oracle VM VirtualBox Extension Pack and VNC, but only one
VRDE module can be active at any time. The following command switches to the VNC VRDE module in VNC:
VBoxManage setproperty vrdeextpack VNC

Conﬁguring the remote access works very similarly to VRDP (see chapter 7.1, Remote display
(VRDP support), page 105), with some limitations: VNC does not support specifying several port numbers, and the authentication is done differently. VNC can only deal with password authentication, and there is no option to use password hashes. This leaves no other choice than having a clear-text password in the VM conﬁguration, which can be set with the following command: VBoxManage modifyvm "VM name" --vrdeproperty VNCPassword=secret

The user is responsible for keeping this password secret, and it should be removed when a
VM conﬁguration is passed to another person, for whatever purpose. Some VNC servers claim to have “encrypted” passwords in the conﬁguration. This is not true encryption, it is only concealing the passwords, which is exactly as secure as clear-text passwords.
The following command switches back to VRDP (if installed):
VBoxManage setproperty vrdeextpack "Oracle VM VirtualBox Extension Pack"

9.24 Starting virtual machines during system boot
Starting with VirtualBox 4.2.0 it is possible to start VMs automatically during system boot on
Linux, Solaris and Mac OS X for all users.

9.24.1 Linux: starting the autostart service via init
On Linux, the autostart service is activated by setting two variables in /etc/default/virtualbox.
The ﬁrst one is VBOXAUTOSTART_DB which contains an absolute path to the autostart database directory. The directory should have write access for every user who should be able to start virtual machines automatically. Furthermore the directory should have the sticky bit set. The second variable is VBOXAUTOSTART_CONFIG which points the service to the autostart conﬁguration ﬁle which is used during boot to determine whether to allow individual users to start a VM automatically and conﬁgure startup delays. The conﬁguration ﬁle can be placed in /etc/vbox and contains several options. One is default_policy which controls whether the autostart service allows or denies to start a VM for users which are not in the exception list. The exception list starts with exception_list and contains a comma separated list with usernames. Furthermore a separate startup delay can be conﬁgured for every user to avoid overloading the host. A sample conﬁguration is given below:
# Default policy is to deny starting a VM, the other option is "allow". default_policy = deny
# Bob is allowed to start virtual machines but starting them
# will be delayed for 10 seconds bob = { allow = true startup_delay = 10
}

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# Alice is not allowed to start virtual machines, useful to exclude certain users
# if the default policy is set to allow. alice = { allow = false
}

Every user who wants to enable autostart for individual machines has to set the path to the autostart database directory with
VBoxManage setproperty autostartdbpath <Autostart directory>

9.24.2 Solaris: starting the autostart service via SMF
On Solaris hosts, the VirtualBox autostart daemon is integrated into the SMF framework. To enable it you have to point the service to an existing conﬁguration ﬁle which has the same format as on Linux (see chapter 9.24.1, Linux: starting the autostart service via init, page 209): svccfg -s svc:/application/virtualbox/autostart:default setprop config/config=/etc/vbox/autostart.cfg

When everything is conﬁgured correctly you can start the VirtualBox autostart service with the following command: svcadm enable svc:/application/virtualbox/autostart:default

For more information about SMF, please refer to the Solaris documentation.

9.24.3 Mac OS X: starting the autostart service via launchd

On Mac OS X, launchd is used to start the VirtualBox autostart service. An example conﬁguration ﬁle can be found in /Applications/VirtualBox.app/Contents/MacOS/org.virtualbox.vboxautostart.plist.
To enable the service copy the ﬁle to /Library/LaunchDaemons and change the Disabled key from true to false. Furthermore replace the second parameter to an existing conﬁguration ﬁle which has the same format as on Linux (see chapter 9.24.1, Linux: starting the autostart service via init, page 209). To manually start the service use the following command: launchctl load /Library/LaunchDaemons/org.virtualbox.vboxautostart.plist

For additional information on how launchd services could be conﬁgured see http:// developer.apple.com/mac/library/documentation/MacOSX/Conceptual/BPSystemStartup/ BPSystemStartup.html.

9.25 VirtualBox expert storage management
In case the snapshot model of VirtualBox is not sufﬁcient it is possible to enable a special mode which makes it possible to reconﬁgure storage attachments while the VM is paused. The user has to make sure that the disk data stays consistent to the guest because unlike with hotplugging the guest is not informed about detached or newly attached media.
The expert storage management mode can be enabled per VM executing:
VBoxManage setextradata "VM name" "VBoxInternal2/SilentReconfigureWhilePaused" 1

Storage attachments can be reconﬁgured while the VM is paused afterwards using:
VBoxManage storageattach ...

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9.26 Handling of host power management events
Some host power management events are handled by VirtualBox. The actual behavior depends on the platform:
Host Suspends This event is generated when the host is about to suspend, that is, the host saves the state to some non-volatile storage and powers off.
This event is currently only handled on Windows hosts and Mac OS X hosts. When this event is generated, VirtualBox will pause all running VMs.
Host Resumes This event is generated when the host woke up from the suspended state.
This event is currently only handled on Windows hosts and Mac OS X hosts. When this event is generated, VirtualBox will resume all VMs which are where paused before.
Battery Low The battery level reached a critical level (usually less than 5 percent charged).
This event is currently only handled on Windows hosts and Mac OS X hosts. When this event is generated, VirtualBox will save the state and terminate all VMs in preperation of a potential host powerdown.
The behavior can be conﬁgured. By executing the following command, no VM is saved:
VBoxManage setextradata global "VBoxInternal2/SavestateOnBatteryLow" 0

This is a global setting as well as a per-VM setting. The per-VM value has higher precedence than the global value. The following command will save the state of all VMs but will not save the state of VM “foo”:
VBoxManage setextradata global "VBoxInternal2/SavestateOnBatteryLow" 1
VBoxManage setextradata "foo" "VBoxInternal2/SavestateOnBatteryLow" 0

The ﬁrst line is actually not required as by default the savestate action is performed.

9.27 Experimental support for passing through SSE4.1 /
SSE4.2 instructions
To provide SSE 4.1 / SSE 4.2 support to guests, the host CPU has to implement these instruction sets. Starting with VirtualBox 4.3.8 it is possible to enable these instructions for certain guests using the following commands:
VBoxManage setextradata "VM name" VBoxInternal/CPUM/SSE4.1 1
VBoxManage setextradata "VM name" VBoxInternal/CPUM/SSE4.2 1

These are a per-VM settings and they are turned off by default.

9.28 Support for keyboard indicators synchronization
This feature makes the host keyboard lights match those of the virtual machine’s virtual keyboard when the machine window is selected. It is currently implemented for Mac OS X and
Windows hosts and available as of releases 4.2.24 and 4.3.8. The feature can be enabled using the following command:
VBoxManage setextradata "VM name" GUI/HidLedsSync "1"

In order to disable it, use the same command but change “1” to “0”, or use the VBoxManage command to remove the extra data. This is a per-VM setting and it is disabled by default.

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9.29 Capturing USB trafﬁc for selected devices
Starting with VirtualBox 5.0 it is possible to capture USB trafﬁc for single USB devices or on the root hub level which captures the trafﬁc of all USB devices attached to the root hub. VirtualBox stores the trafﬁc in a format which is compatible with Wireshark. To capture the trafﬁc of a speciﬁc USB device it must be attached to the VM with VBoxManage using the following command:
VBoxManage controlvm "VM name" usbattach "device uuid|address" --capturefile "filename"

In order to enable capturing on the root hub use the following command while the VM is not running: VBoxManage setextradata "VM name" VBoxInternal/Devices/usb-ehci/LUN#0/Config/CaptureFilename "filename"

The command above enables capturing on the root hub attached to the EHCI controller. To enable it for the OHCI or XHCI controller replace usb-ehci with usb-ohci or usb-xhci respectively.

9.30 Conﬁguring the heartbeat service
VirtualBox ships a simple heartbeat service. Once the Guest Additions are active, the guest sends frequent heartbeat pings to the host. If the guest stops sending the heartbeat pings without properly termination the service, the VM process will log this event in the VBox.log ﬁle. In the future it might be possible to conﬁgure dedicated actions but for there is only a warning in the log ﬁle.
There are two parameters to conﬁgure. The heartbeat interval deﬁnes the time between two heartbeat pings. The default value is 2 seconds, that is, the heartbeat service of the VirtualBox
Guest Additions will send a heartbeat ping every two seconds. The value in nanoseconds can be conﬁgured like this:
VBoxManage controlvm "VM name" VBoxInternal/Devices/VMMDev/0/Config/HeartbeatInterval 2000000000

The heartbeat timeout deﬁnes the time the host waits starting from the last heartbeat ping before it deﬁnes the guest as unresponsive. The default value is 2 times the heartbeat interval (4 seconds) and can be conﬁgured as following (in nanoseconds):
VBoxManage controlvm "VM name" VBoxInternal/Devices/VMMDev/0/Config/HeartbeatTimeout 4000000000

If the heartbeat timeout expires, there will be a log message like VMMDev: HeartBeatCheckTimer: Guest seems to be unresponsive. Last heartbeat received 5 seconds ago. If another heartbeat ping arrives after this warning, there will be a log message like VMMDev: GuestHeartBeat: Guest is alive.

9.31 Encryption of disk images
Starting with VirtualBox 5.0, it is possible to encrypt the data stored in hard disk images transparently for the guest. It does not depend on a speciﬁc image format to be used. Images which have the data encrypted are not portable between VirtualBox and other virtualization software.
VirtualBox uses the AES algorithm in XTS mode and supports 128 or 256 bit data encryption keys (DEK). The DEK is stored encrypted in the medium properties and is decrypted during VM startup by entering a password which was chosen when the image was encrypted.
Since the DEK is stored as part of the VM conﬁguration ﬁle, it is important that it is kept safe. Losing the DEK means that the data stored in the disk images is lost irrecoverably. Having complete and up to date backups of all data related to the VM is the responsibility of the user.

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9.31.1 Limitations
There are some limitations the user needs to be aware of when using this feature:
• This feature is part of the Oracle VM VirtualBox Extension Pack, which needs to be installed.
Otherwise disk encryption is unavailable.
• Since encryption works only on the stored user data, it is currently not possible to check for metadata integrity of the disk image. Attackers might destroy data by removing or changing blocks of data in the image or change metadata items such as the disk size.
• Exporting appliances which contain encrypted disk images is not possible because the OVF speciﬁcation doesn’t support this. All images are therefore decrypted during export.
• The DEK is kept in memory while the VM is running to be able to decrypt data read and encrypt data written by the guest. While this should be obvious the user needs to be aware of this because an attacker might be able to extract the key on a compromised host and decrypt the data.
• When encrypting or decrypting the images, the password is passed in clear text via the
VirtualBox API. This needs to be kept in mind, especially when using third party API clients which make use of the webservice where the password might be transmitted over the network. The use of HTTPS is mandatory in such a case.
• Encrypting images with differencing images is only possible if there are no snapshots or a linear chain of snapshots. This limitation may be addressed in a future VirtualBox version.

9.31.2 Encrypting disk images
Encrypting disk images can be done either using the GUI or VBoxManage. While the GUI is easier to use, it works on a per VM basis and encrypts all disk images attached to the speciﬁc VM. With
VBoxManage one can encrypt individual images (including all differencing images). To encrypt an unencrypted medium with VBoxManage, use:
VBoxManage encryptmedium "uuid|filename" --newpassword "file|-" --cipher "cipher id" --newpasswordid "id"

To supply the encryption password point VBoxManage to the ﬁle where the password is stored or specify - to let VBoxManage ask you for the password on the command line.
The cipher parameter speciﬁes the cipher to use for encryption and can be either
AES-XTS128-PLAIN64 or AES-XTS256-PLAIN64. The speciﬁed password identiﬁer can be freely chosen by the user and is used for correct identiﬁcation when supplying multiple passwords during VM startup.
If the user uses the same password when encrypting multiple images and also the same password identiﬁer, the user needs to supply the password only once during VM startup.

9.31.3 Starting a VM with encrypted images
When a VM is started using the GUI, a dialog will open where the user needs to enter all passwords for all encrypted images attached to the VM. If another frontend like VBoxHeadless is used, the VM will be paused as soon as the guest tries to access an encrypted disk. The user needs to provide the passwords through VBoxManage using the following command:
VBoxManage controlvm "uuid|vmname" addencpassword "id" "password" [--removeonsuspend "yes|no"]

The id parameter must be the same as the password identiﬁer supplied when encrypting the images. password is the password used when encrypting the images. The user can optionally specify --removeonsuspend "yes|no" to specify whether to remove the password from VM memory when the VM is suspended. Before the VM can be resumed, the user needs to supply the passwords again. This is useful when a VM is suspended by a host suspend event and the user doesn’t want the password to remain in memory.

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9.31.4 Decrypting encrypted images
In some circumstances it might be required to decrypt previously encrypted images. This can be done in the GUI for a complete VM or using VBoxManage with the following command:
VBoxManage encryptmedium "uuid|filename" --oldpassword "file|-"

The only required parameter is the password the image was encrypted with. The options are the same as for encrypting images.

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The contents of this chapter are not required to use VirtualBox successfully. The following is provided as additional information for readers who are more familiar with computer architecture and technology and wish to ﬁnd out more about how VirtualBox works “under the hood”.

10.1 Where VirtualBox stores its ﬁles
In VirtualBox, a virtual machine and its settings are described in a virtual machine settings ﬁle in XML format. In addition, most virtual machine have one or more virtual hard disks, which are typically represented by disk images (e.g. in VDI format). Where all these ﬁles are stored depends on which version of VirtualBox created the machine.

10.1.1 Machines created by VirtualBox version 4.0 or later
Starting with version 4.0, by default, each virtual machine has one directory on your host computer where all the ﬁles of that machine are stored – the XML settings ﬁle (with a .vbox ﬁle extension) and its disk images.
By default, this “machine folder” is placed in a common folder called “VirtualBox VMs”, which
VirtualBox creates in the current system user’s home directory. The location of this home directory depends on the conventions of the host operating system:
• On Windows, this is %HOMEDRIVE%%HOMEPATH%; typically something like C:\Documents and Settings\Username\.
• On Mac OS X, this is /Users/username.
• On Linux and Solaris, this is /home/username.
For simplicity, we will abbreviate this as $HOME below. Using that convention, the common folder for all virtual machines is $HOME/VirtualBox VMs.
As an example, when you create a virtual machine called “Example VM”, you will ﬁnd that
VirtualBox creates
1. the folder $HOME/VirtualBox VMs/Example VM/ and, in that folder,
2. the settings ﬁle Example VM.vbox and
3. the virtual disk image Example VM.vdi.
This is the default layout if you use the “Create new virtual machine” wizard as described in chapter 1.7, Creating your ﬁrst virtual machine, page 17. Once you start working with the VM, additional ﬁles will show up: you will ﬁnd log ﬁles in a subfolder called Logs, and once you have taken snapshots, they will appear in a Snapshots subfolder. For each VM, you can change the location of its snapsnots folder in the VM settings.
You can change the default machine folder by selecting “Preferences” from the “File” menu in the VirtualBox main window. Then, in the window that pops up, click on the “General” tab.
Alternatively, use VBoxManage setproperty machinefolder; see chapter 8.27, VBoxManage setproperty, page 151.

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10.1.2 Machines created by VirtualBox versions before 4.0
If you have upgraded to VirtualBox 4.0 from an earlier version of VirtualBox, you probably have settings ﬁles and disks in the earlier ﬁle system layout.
Before version 4.0, VirtualBox separated the machine settings ﬁles from virtual disk images.
The machine settings ﬁles had an .xml ﬁle extension and resided in a folder called “Machines” under the global VirtualBox conﬁguration directory (see the next section). So, for example, on
Linux, this was the hidden $HOME/.VirtualBox/Machines directory. The default hard disks folder was called “HardDisks” and resided in the .VirtualBox folder as well. Both locations could be changed by the user in the global preferences. (The concept of a “default hard disk folder” has been abandoned with VirtualBox 4.0, since disk images now reside in each machine’s folder by default.)
The old layout had several severe disadvantages.
1. It was very difﬁcult to move a virtual machine from one host to another because the ﬁles involved did not reside in the same folder. In addition, the virtual media of all machines were registered with a global registry in the central VirtualBox settings ﬁle
($HOME/.VirtualBox/VirtualBox.xml).
To move a machine to another host, it was therefore not enough to move the XML settings ﬁle and the disk images (which were in different locations), but the hard disk entries from the global media registry XML had to be meticulously copied as well, which was close to impossible if the machine had snapshots and therefore differencing images.
2. Storing virtual disk images, which can grow very large, under the hidden .VirtualBox directory (at least on Linux and Solaris hosts) made many users wonder where their disk space had gone.
Whereas new VMs created with VirtualBox 4.0 or later will conform to the new layout, for maximum compatibility, old VMs are not converted to the new layout. Otherwise machine settings would be irrevocably broken if a user downgraded from 4.0 back to an older version of
VirtualBox.

10.1.3 Global conﬁguration data
In addition to the ﬁles of the virtual machines, VirtualBox maintains global conﬁguration data. On Linux and Solaris as of VirtualBox 4.3, this is in the hidden directory
$HOME/.config/VirtualBox, although $HOME/.VirtualBox will be used if it exists for compatibility with earlier versions; on Windows (and on Linux and Solaris with VirtualBox 4.2 and earlier) this is in $HOME/.VirtualBox; on a Mac it resides in $HOME/Library/VirtualBox.
VirtualBox creates this conﬁguration directory automatically if necessary. Optionally, you can supply an alternate conﬁguration directory by setting the VBOX_USER_HOME environment variable, or additionally on Linux or Solaris by using the standard XDG_CONFIG_HOME variable. (Since the global VirtualBox.xml settings ﬁle points to all other conﬁguration ﬁles, this allows for switching between several VirtualBox conﬁgurations entirely.)
Most importantly, in this directory, VirtualBox stores its global settings ﬁle, another XML ﬁle called VirtualBox.xml. This includes global conﬁguration options and the list of registered virtual machines with pointers to their XML settings ﬁles. (Neither the location of this ﬁle nor its directory has changed with VirtualBox 4.0.)
Before VirtualBox 4.0, all virtual media (disk image ﬁles) were also contained in a global registry in this settings ﬁle. For compatibility, this media registry still exists if you upgrade
VirtualBox and there are media from machines which were created with a version before 4.0.
If you have no such machines, then there will be no global media registry; with VirtualBox 4.0, each machine XML ﬁle has its own media registry.
Also before VirtualBox 4.0, the default “Machines” folder and the default “HardDisks” folder resided under the VirtualBox conﬁguration directory (e.g. $HOME/.VirtualBox/Machines on

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Linux). If you are upgrading from a VirtualBox version before 4.0, ﬁles in these directories are not automatically moved in order not to break backwards compatibility.

10.1.4 Summary of 4.0 conﬁguration changes
The following table gives a brief overview of the conﬁguration changes between older versions and version 4.0 or above:
Setting
Default machines folder

Before 4.0

4.0 or above

$HOME/.VirtualBox/Machines

$HOME/VirtualBox
VMs

Default disk image location
Machine settings ﬁle extension Media registry

$HOME/.VirtualBox/HardDisks In each machine’s folder
.xml
.vbox

Media registration

Explicit open/close required

Global VirtualBox.xml ﬁle

Each machine settings ﬁle Automatic on attach

10.1.5 VirtualBox XML ﬁles
VirtualBox uses XML for both the machine settings ﬁles and the global conﬁguration ﬁle,
VirtualBox.xml.
All VirtualBox XML ﬁles are versioned. When a new settings ﬁle is created (e.g. because a new virtual machine is created), VirtualBox automatically uses the settings format of the current
VirtualBox version. These ﬁles may not be readable if you downgrade to an earlier version of
VirtualBox. However, when VirtualBox encounters a settings ﬁle from an earlier version (e.g. after upgrading VirtualBox), it attempts to preserve the settings format as much as possible. It will only silently upgrade the settings format if the current settings cannot be expressed in the old format, for example because you enabled a feature that was not present in an earlier version of VirtualBox.1 In such cases, VirtualBox backs up the old settings ﬁle in the virtual machine’s conﬁguration directory. If you need to go back to the earlier version of VirtualBox, then you will need to manually copy these backup ﬁles back.
We intentionally do not document the speciﬁcations of the VirtualBox XML ﬁles, as we must reserve the right to modify them in the future. We therefore strongly suggest that you do not edit these ﬁles manually. VirtualBox provides complete access to its conﬁguration data through its the VBoxManage command line tool (see chapter 8, VBoxManage, page 115) and its API (see chapter 11, VirtualBox programming interfaces, page 225).

10.2 VirtualBox executables and components
VirtualBox was designed to be modular and ﬂexible. When the VirtualBox graphical user interface (GUI) is opened and a VM is started, at least three processes are running:
1. VBoxSVC, the VirtualBox service process which always runs in the background. This process is started automatically by the ﬁrst VirtualBox client process (the GUI, VBoxManage,
VBoxHeadless, the web service or others) and exits a short time after the last client exits.
The service is responsible for bookkeeping, maintaining the state of all VMs, and for providing communication between VirtualBox components. This communication is implemented via COM/XPCOM.
1 As

an example, before VirtualBox 3.1, it was only possible to enable or disable a single DVD drive in a virtual machine.
If it was enabled, then it would always be visible as the secondary master of the IDE controller. With VirtualBox 3.1,
DVD drives can be attached to arbitrary slots of arbitrary controllers, so they could be the secondary slave of an IDE controller or in a SATA slot. If you have a machine settings ﬁle from an earlier version and upgrade VirtualBox to 3.1 and then move the DVD drive from its default position, this cannot be expressed in the old settings format; the XML machine ﬁle would get written in the new format, and a backup ﬁle of the old format would be kept.

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Note: When we refer to “clients” here, we mean the local clients of a particular VBoxSVC server process, not clients in a network. VirtualBox employs its own client/server design to allow its processes to cooperate, but all these processes run under the same user account on the host operating system, and this is totally transparent to the user.
2. The GUI process, VirtualBox, a client application based on the cross-platform Qt library. When started without the --startvm option, this application acts as the VirtualBox manager, displaying the VMs and their settings. It then communicates settings and state changes to VBoxSVC and also reﬂects changes effected through other means, e.g.,
VBoxManage.
3. If the VirtualBox client application is started with the --startvm argument, it loads the
VMM library which includes the actual hypervisor and then runs a virtual machine and provides the input and output for the guest.
Any VirtualBox front-end (client) will communicate with the service process and can both control and reﬂect the current state. For example, either the VM selector or the VM window or
VBoxManage can be used to pause the running VM, and other components will always reﬂect the changed state.
The VirtualBox GUI application is only one of several available front ends (clients). The complete list shipped with VirtualBox is:
1. VirtualBox, the Qt front end implementing the manager and running VMs;
2. VBoxManage, a less user-friendly but more powerful alternative, described in chapter 8,
VBoxManage, page 115.
3. VBoxSDL, a simple graphical front end based on the SDL library; see chapter 9.1, VBoxSDL, the simpliﬁed VM displayer, page 171.
4. VBoxHeadless, a VM front end which does not directly provide any video output and keyboard/mouse input, but allows redirection via VirtualBox Remote Desktop Extension; see chapter 7.1.2, VBoxHeadless, the remote desktop server, page 106.
5. vboxwebsrv, the VirtualBox web service process which allows for controlling a VirtualBox host remotely. This is described in detail in the VirtualBox Software Development Kit (SDK) reference; please see chapter 11, VirtualBox programming interfaces, page 225 for details.
6. The VirtualBox Python shell, a Python alternative to VBoxManage. This is also described in the SDK reference.
Internally, VirtualBox consists of many more or less separate components. You may encounter these when analyzing VirtualBox internal error messages or log ﬁles. These include:
• IPRT, a portable runtime library which abstracts ﬁle access, threading, string manipulation, etc. Whenever VirtualBox accesses host operating features, it does so through this library for cross-platform portability.
• VMM (Virtual Machine Monitor), the heart of the hypervisor.
• EM (Execution Manager), controls execution of guest code.
• REM (Recompiled Execution Monitor), provides software emulation of CPU instructions.
• TRPM (Trap Manager), intercepts and processes guest traps and exceptions.
• HWACCM (Hardware Acceleration Manager), provides support for VT-x and AMD-V.

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• PDM (Pluggable Device Manager), an abstract interface between the VMM and emulated devices which separates device implementations from VMM internals and makes it easy to add new emulated devices. Through PDM, third-party developers can add new virtual devices to VirtualBox without having to change VirtualBox itself.
• PGM (Page Manager), a component controlling guest paging.
• PATM (Patch Manager), patches guest code to improve and speed up software virtualization.
• TM (Time Manager), handles timers and all aspects of time inside guests.
• CFGM (Conﬁguration Manager), provides a tree structure which holds conﬁguration settings for the VM and all emulated devices.
• SSM (Saved State Manager), saves and loads VM state.
• VUSB (Virtual USB), a USB layer which separates emulated USB controllers from the controllers on the host and from USB devices; this also enables remote USB.
• DBGF (Debug Facility), a built-in VM debugger.
• VirtualBox emulates a number of devices to provide the hardware environment that various guests need. Most of these are standard devices found in many PC compatible machines and widely supported by guest operating systems. For network and storage devices in particular, there are several options for the emulated devices to access the underlying hardware. These devices are managed by PDM.
• Guest Additions for various guest operating systems. This is code that is installed from within a virtual machine; see chapter 4, Guest Additions, page 59.
• The “Main” component is special: it ties all the above bits together and is the only public
API that VirtualBox provides. All the client processes listed above use only this API and never access the hypervisor components directly. As a result, third-party applications that use the VirtualBox Main API can rely on the fact that it is always well-tested and that all capabilities of VirtualBox are fully exposed. It is this API that is described in the VirtualBox
SDK mentioned above (again, see chapter 11, VirtualBox programming interfaces, page
225).

10.3 Hardware vs. software virtualization
VirtualBox allows software in the virtual machine to run directly on the processor of the host, but an array of complex techniques is employed to intercept operations that would interfere with your host. Whenever the guest attempts to do something that could be harmful to your computer and its data, VirtualBox steps in and takes action. In particular, for lots of hardware that the guest believes to be accessing, VirtualBox simulates a certain “virtual” environment according to how you have conﬁgured a virtual machine. For example, when the guest attempts to access a hard disk, VirtualBox redirects these requests to whatever you have conﬁgured to be the virtual machine’s virtual hard disk – normally, an image ﬁle on your host.
Unfortunately, the x86 platform was never designed to be virtualized. Detecting situations in which VirtualBox needs to take control over the guest code that is executing, as described above, is difﬁcult. There are two ways in which to achieve this:
• Since 2006, Intel and AMD processors have had support for so-called “hardware virtualization”. This means that these processors can help VirtualBox to intercept potentially dangerous operations that a guest operating system may be attempting and also makes it easier to present virtual hardware to a virtual machine.

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These hardware features differ between Intel and AMD processors. Intel named its technology VT-x; AMD calls theirs AMD-V. The Intel and AMD support for virtualization is very different in detail, but not very different in principle.
Note: On many systems, the hardware virtualization features ﬁrst need to be enabled in the BIOS before VirtualBox can use them.
• As opposed to other virtualization software, for many usage scenarios, VirtualBox does not require hardware virtualization features to be present. Through sophisticated techniques,
VirtualBox virtualizes many guest operating systems entirely in software. This means that you can run virtual machines even on older processors which do not support hardware virtualization. Even though VirtualBox does not always require hardware virtualization, enabling it is required in the following scenarios:
• Certain rare guest operating systems like OS/2 make use of very esoteric processor instructions that are not supported with our software virtualization. For virtual machines that are conﬁgured to contain such an operating system, hardware virtualization is enabled automatically. • VirtualBox’s 64-bit guest support (added with version 2.0) and multiprocessing (SMP, added with version 3.0) both require hardware virtualization to be enabled. (This is not much of a limitation since the vast majority of today’s 64-bit and multicore CPUs ship with hardware virtualization anyway; the exceptions to this rule are e.g. older Intel Celeron and
AMD Opteron CPUs.)

Warning: Do not run other hypervisors (open-source or commercial virtualization products) together with VirtualBox! While several hypervisors can normally be installed in parallel, do not attempt to run several virtual machines from competing hypervisors at the same time. VirtualBox cannot track what another hypervisor is currently attempting to do on the same host, and especially if several products attempt to use hardware virtualization features such as VT-x, this can crash the entire host. Also, within VirtualBox, you can mix software and hardware virtualization when running multiple VMs. In certain cases a small performance penalty will be unavoidable when mixing VT-x and software virtualization VMs. We recommend not mixing virtualization modes if maximum performance and low overhead are essential. This does not apply to AMD-V.

10.4 Paravirtualization providers
VirtualBox allows exposing a paravirtualization interface to facilitate accurate and efﬁcient execution of software within a virtual machine. These interfaces require the guest operating system to recognize their presence and make use of them in order to leverage the beneﬁts of communicating with the VirtualBox hypervisor.
Most mainstream, modern operating systems, including Windows and Linux, ship with support for one or more paravirtualization interfaces. Hence, there is typically no need to install additional software in the guest (including VirtualBox Guest Additions) to make use of this feature.
VirtualBox provides the following interfaces:

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• Minimal: Announces the presence of a virtualized environment. Additionally, reports the
TSC and APIC frequency to the guest operating system. This provider is mandatory for running any Mac OS X guests.
• KVM: Presents a Linux KVM hypervisor interface which is recognized by Linux kernels starting with version 2.6.25. VirtualBox’s implementation currently supports paravirtualized clocks and SMP spinlocks. This provider is recommended for Linux guests.
• Hyper-V: Presents a Microsoft Hyper-V hypervisor interface which is recognized by Windows 7 and newer operating systems. VirtualBox’s implementation currently supports paravirtualized clocks, APIC frequency reporting and relaxed timer checks. This provider is recommended for Windows and FreeBSD guests.

10.5 Details about software virtualization
Implementing virtualization on x86 CPUs with no hardware virtualization support is an extraordinarily complex task because the CPU architecture was not designed to be virtualized. The problems can usually be solved, but at the cost of reduced performance. Thus, there is a constant clash between virtualization performance and accuracy.
The x86 instruction set was originally designed in the 1970s and underwent signiﬁcant changes with the addition of protected mode in the 1980s with the 286 CPU architecture and then again with the Intel 386 and its 32-bit architecture. Whereas the 386 did have limited virtualization support for real mode operation (V86 mode, as used by the “DOS Box” of Windows
3.x and OS/2 2.x), no support was provided for virtualizing the entire architecture.
In theory, software virtualization is not overly complex. In addition to the four privilege levels
(“rings”) provided by the hardware (of which typically only two are used: ring 0 for kernel mode and ring 3 for user mode), one needs to differentiate between “host context” and “guest context”.
In “host context”, everything is as if no hypervisor was active. This might be the active mode if another application on your host has been scheduled CPU time; in that case, there is a host ring
3 mode and a host ring 0 mode. The hypervisor is not involved.
In “guest context”, however, a virtual machine is active. So long as the guest code is running in ring 3, this is not much of a problem since a hypervisor can set up the page tables properly and run that code natively on the processor. The problems mostly lie in how to intercept what the guest’s kernel does.
There are several possible solutions to these problems. One approach is full software emulation, usually involving recompilation. That is, all code to be run by the guest is analyzed, transformed into a form which will not allow the guest to either modify or see the true state of the CPU, and only then executed. This process is obviously highly complex and costly in terms of performance. (VirtualBox contains a recompiler based on QEMU which can be used for pure software emulation, but the recompiler is only activated in special situations, described below.)
Another possible solution is paravirtualization, in which only specially modiﬁed guest OSes are allowed to run. This way, most of the hardware access is abstracted and any functions which would normally access the hardware or privileged CPU state are passed on to the hypervisor instead. Paravirtualization can achieve good functionality and performance on standard x86
CPUs, but it can only work if the guest OS can actually be modiﬁed, which is obviously not always the case.
VirtualBox chooses a different approach. When starting a virtual machine, through its ring-0 support kernel driver, VirtualBox has set up the host system so that it can run most of the guest code natively, but it has inserted itself at the “bottom” of the picture. It can then assume control when needed – if a privileged instruction is executed, the guest traps (in particular because an I/O register was accessed and a device needs to be virtualized) or external interrupts occur.
VirtualBox may then handle this and either route a request to a virtual device or possibly delegate handling such things to the guest or host OS. In guest context, VirtualBox can therefore be in one of three states:

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• Guest ring 3 code is run unmodiﬁed, at full speed, as much as possible. The number of faults will generally be low (unless the guest allows port I/O from ring 3, something we cannot do as we don’t want the guest to be able to access real ports). This is also referred to as “raw mode”, as the guest ring-3 code runs unmodiﬁed.
• For guest code in ring 0, VirtualBox employs a nasty trick: it actually reconﬁgures the guest so that its ring-0 code is run in ring 1 instead (which is normally not used in x86 operating systems). As a result, when guest ring-0 code (actually running in ring 1) such as a guest device driver attempts to write to an I/O register or execute a privileged instruction, the
VirtualBox hypervisor in “real” ring 0 can take over.
• The hypervisor (VMM) can be active. Every time a fault occurs, VirtualBox looks at the offending instruction and can relegate it to a virtual device or the host OS or the guest OS or run it in the recompiler.
In particular, the recompiler is used when guest code disables interrupts and VirtualBox cannot ﬁgure out when they will be switched back on (in these situations, VirtualBox actually analyzes the guest code using its own disassembler). Also, certain privileged instructions such as LIDT need to be handled specially. Finally, any real-mode or protected-mode code (e.g. BIOS code, a DOS guest, or any operating system startup) is run in the recompiler entirely.
Unfortunately this only works to a degree. Among others, the following situations require special handling:
1. Running ring 0 code in ring 1 causes a lot of additional instruction faults, as ring 1 is not allowed to execute any privileged instructions (of which guest’s ring-0 contains plenty).
With each of these faults, the VMM must step in and emulate the code to achieve the desired behavior. While this works, emulating thousands of these faults is very expensive and severely hurts the performance of the virtualized guest.
2. There are certain ﬂaws in the implementation of ring 1 in the x86 architecture that were never ﬁxed. Certain instructions that should trap in ring 1 don’t. This affects, for example, the LGDT/SGDT, LIDT/SIDT, or POPF/PUSHF instruction pairs. Whereas the “load” operation is privileged and can therefore be trapped, the “store” instruction always succeed. If the guest is allowed to execute these, it will see the true state of the CPU, not the virtualized state. The CPUID instruction also has the same problem.
3. A hypervisor typically needs to reserve some portion of the guest’s address space (both linear address space and selectors) for its own use. This is not entirely transparent to the guest OS and may cause clashes.
4. The SYSENTER instruction (used for system calls) executed by an application running in a guest OS always transitions to ring 0. But that is where the hypervisor runs, not the guest
OS. In this case, the hypervisor must trap and emulate the instruction even when it is not desirable. 5. The CPU segment registers contain a “hidden” descriptor cache which is not softwareaccessible. The hypervisor cannot read, save, or restore this state, but the guest OS may use it.
6. Some resources must (and can) be trapped by the hypervisor, but the access is so frequent that this creates a signiﬁcant performance overhead. An example is the TPR (Task Priority) register in 32-bit mode. Accesses to this register must be trapped by the hypervisor, but certain guest operating systems (notably Windows and Solaris) write this register very often, which adversely affects virtualization performance.

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To ﬁx these performance and security issues, VirtualBox contains a Code Scanning and Analysis
Manager (CSAM), which disassembles guest code, and the Patch Manager (PATM), which can replace it at runtime.
Before executing ring 0 code, CSAM scans it recursively to discover problematic instructions.
PATM then performs in-situ patching, i.e. it replaces the instruction with a jump to hypervisor memory where an integrated code generator has placed a more suitable implementation. In reality, this is a very complex task as there are lots of odd situations to be discovered and handled correctly. So, with its current complexity, one could argue that PATM is an advanced in-situ recompiler. In addition, every time a fault occurs, VirtualBox analyzes the offending code to determine if it is possible to patch it in order to prevent it from causing more faults in the future. This approach works well in practice and dramatically improves software virtualization performance.

10.6 Details about hardware virtualization
With Intel VT-x, there are two distinct modes of CPU operation: VMX root mode and non-root mode. • In root mode, the CPU operates much like older generations of processors without VT-x support. There are four privilege levels (“rings”), and the same instruction set is supported, with the addition of several virtualization speciﬁc instruction. Root mode is what a host operating system without virtualization uses, and it is also used by a hypervisor when virtualization is active.
• In non-root mode, CPU operation is signiﬁcantly different. There are still four privilege rings and the same instruction set, but a new structure called VMCS (Virtual Machine Control Structure) now controls the CPU operation and determines how certain instructions behave. Non-root mode is where guest systems run.
Switching from root mode to non-root mode is called “VM entry”, the switch back is “VM exit”.
The VMCS includes a guest and host state area which is saved/restored at VM entry and exit.
Most importantly, the VMCS controls which guest operations will cause VM exits.
The VMCS provides fairly ﬁne-grained control over what the guests can and can’t do. For example, a hypervisor can allow a guest to write certain bits in shadowed control registers, but not others. This enables efﬁcient virtualization in cases where guests can be allowed to write control bits without disrupting the hypervisor, while preventing them from altering control bits over which the hypervisor needs to retain full control. The VMCS also provides control over interrupt delivery and exceptions.
Whenever an instruction or event causes a VM exit, the VMCS contains information about the exit reason, often with accompanying detail. For example, if a write to the CR0 register causes an exit, the offending instruction is recorded, along with the fact that a write access to a control register caused the exit, and information about source and destination register. Thus the hypervisor can efﬁciently handle the condition without needing advanced techniques such as
CSAM and PATM described above.
VT-x inherently avoids several of the problems which software virtualization faces. The guest has its own completely separate address space not shared with the hypervisor, which eliminates potential clashes. Additionally, guest OS kernel code runs at privilege ring 0 in VMX non-root mode, obviating the problems by running ring 0 code at less privileged levels. For example the
SYSENTER instruction can transition to ring 0 without causing problems. Naturally, even at ring
0 in VMX non-root mode, any I/O access by guest code still causes a VM exit, allowing for device emulation. The biggest difference between VT-x and AMD-V is that AMD-V provides a more complete virtualization environment. VT-x requires the VMX non-root code to run with paging enabled,

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10 Technical background which precludes hardware virtualization of real-mode code and non-paged protected-mode software. This typically only includes ﬁrmware and OS loaders, but nevertheless complicates VT-x hypervisor implementation. AMD-V does not have this restriction.
Of course hardware virtualization is not perfect. Compared to software virtualization, the overhead of VM exits is relatively high. This causes problems for devices whose emulation requires high number of traps. One example is the VGA device in 16-color modes, where not only every I/O port access but also every access to the framebuffer memory must be trapped.

10.7 Nested paging and VPIDs
In addition to “plain” hardware virtualization, your processor may also support additional sophisticated techniques:2
• A newer feature called “nested paging” implements some memory management in hardware, which can greatly accelerate hardware virtualization since these tasks no longer need to be performed by the virtualization software.
With nested paging, the hardware provides another level of indirection when translating linear to physical addresses. Page tables function as before, but linear addresses are now translated to “guest physical” addresses ﬁrst and not physical addresses directly. A new set of paging registers now exists under the traditional paging mechanism and translates from guest physical addresses to host physical addresses, which are used to access memory.
Nested paging eliminates the overhead caused by VM exits and page table accesses. In essence, with nested page tables the guest can handle paging without intervention from the hypervisor. Nested paging thus signiﬁcantly improves virtualization performance.
On AMD processors, nested paging has been available starting with the Barcelona (K10) architecture – they call it now “rapid virtualization indexing” (RVI). Intel added support for nested paging, which they call “extended page tables” (EPT), with their Core i7 (Nehalem) processors. If nested paging is enabled, the VirtualBox hypervisor can also use large pages to reduce
TLB usage and overhead. This can yield a performance improvement of up to 5%. To enable this feature for a VM, you need to use the VBoxManage modifyvm --largepages command; see chapter 8.8, VBoxManage modifyvm, page 129.
• On Intel CPUs, another hardware feature called “Virtual Processor Identiﬁers” (VPIDs) can greatly accelerate context switching by reducing the need for expensive ﬂushing of the processor’s Translation Lookaside Buffers (TLBs).
To enable these features for a VM, you need to use the VBoxManage modifyvm --vtxvpid and --largepages commands; see chapter 8.8, VBoxManage modifyvm, page 129.

2 VirtualBox

2.0 added support for AMD’s nested paging; support for Intel’s EPT and VPIDs was added with version 2.1.

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11 VirtualBox programming interfaces
VirtualBox comes with comprehensive support for third-party developers. The so-called “Main
API” of VirtualBox exposes the entire feature set of the virtualization engine. It is completely documented and available to anyone who wishes to control VirtualBox programmatically.
The Main API is made available to C++ clients through COM (on Windows hosts) or XPCOM
(on other hosts). Bridges also exist for SOAP, Java and Python.
All programming information (documentation, reference information, header and other interface ﬁles as well as samples) have been split out to a separate Software Development Kit
(SDK), which is available for download from http://www.virtualbox.org. In particular, the
SDK comes with a “Programming Guide and Reference” in PDF format, which contains, among other things, the information that was previously in this chapter of the User Manual.

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12 Troubleshooting
This chapter provides answers to commonly asked questions. In order to improve your user experience with VirtualBox, it is recommended to read this section to learn more about common pitfalls and get recommendations on how to use the product.

12.1 Procedures and tools
12.1.1 Categorizing and isolating problems
More often than not, a virtualized guest behaves like a physical system. Any problems that a physical machine would encounter, a virtual machine will encounter as well. If, for example,
Internet connectivity is lost due to external issues, virtual machines will be affected just as much as physical ones.
If a true VirtualBox problem is encountered, it helps to categorize and isolate the problem ﬁrst.
Here are some of the questions that should be answered before reporting a problem:
1. Is the problem speciﬁc to a certain guest OS? Speciﬁc release of a guest OS? Especially with Linux guest related problems, the issue may be speciﬁc to a certain distribution and version of Linux.
2. Is the problem speciﬁc to a certain host OS? Problems are usually not host OS speciﬁc
(because most of the VirtualBox code base is shared across all supported platforms), but especially in the areas of networking and USB support, there are signiﬁcant differences between host platforms. Some GUI related issues are also host speciﬁc.
3. Is the problem speciﬁc to certain host hardware? This category of issues is typically related to the host CPU. Because of signiﬁcant differences between VT-x and AMD-V, problems may be speciﬁc to one or the other technology. The exact CPU model may also make a difference
(even for software virtualization) because different CPUs support different features, which may affect certain aspects of guest CPU operation.
4. Is the problem speciﬁc to a certain virtualization mode? Some problems may only occur in software virtualization mode, others may be speciﬁc to hardware virtualization.
5. Is the problem speciﬁc to guest SMP? That is, is it related to the number of virtual CPUs
(VCPUs) in the guest? Using more than one CPU usually signiﬁcantly affects the internal operation of a guest OS.
6. Is the problem speciﬁc to the Guest Additions? In some cases, this is a given (e.g., a shared folders problem), in other cases it may be less obvious (for example, display problems).
And if the problem is Guest Additions speciﬁc, is it also speciﬁc to a certain version of the
Additions?
7. Is the problem speciﬁc to a certain environment? Some problems are related to a particular environment external to the VM; this usually involves network setup. Certain conﬁgurations of external servers such as DHCP or PXE may expose problems which do not occur with other, similar servers.
8. Is the problem a regression? Knowing that an issue is a regression usually makes it signiﬁcantly easier to ﬁnd the solution. In this case, it is crucial to know which version is affected and which is not.

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12.1.2 Collecting debugging information
For problem determination, it is often important to collect debugging information which can be analyzed by VirtualBox support. This section contains information about what kind of information can be obtained.
Every time VirtualBox starts up a VM, a so-called “release log ﬁle” is created containing lots of information about the VM conﬁguration and runtime events. The log ﬁle is called VBox.log and resides in the VM log ﬁle folder. Typically this will be a directory like this:
$HOME/VirtualBox VMs/{machinename}/Logs

When starting a VM, the conﬁguration ﬁle of the last run will be renamed to .1, up to .3.
Sometimes when there is a problem, it is useful to have a look at the logs. Also when requesting support for VirtualBox, supplying the corresponding log ﬁle is mandatory.
For convenience, for each virtual machine, the VirtualBox main window can show these logs in a window. To access it, select a virtual machine from the list on the left and select “Show logs...“ from the “Machine” window.
The release log ﬁle (VBox.log) contains a wealth of diagnostic information, such as Host OS type and version, VirtualBox version and build (32-bit or 64-bit), a complete dump of the guest’s conﬁguration (CFGM), detailed information about the host CPU type and supported features, whether hardware virtualization is enabled, information about VT-x/AMD-V setup, state transitions (creating, running, paused, stopping, etc.), guest BIOS messages, Guest Additions messages, device-speciﬁc log entries and, at the end of execution, ﬁnal guest state and condensed statistics. In case of crashes, it is very important to collect crash dumps. This is true for both host and guest crashes. For information about enabling core dumps on Linux, Solaris, and OS X systems, refer to the core dump article on the VirtualBox website.1
You can also use VBoxManage debugvm to create a dump of a complete virtual machine; see chapter 8.35, VBoxManage debugvm, page 163.
For network related problems, it is often helpful to capture a trace of network trafﬁc. If the trafﬁc is routed through an adapter on the host, it is possible to use Wireshark or a similar tool to capture the trafﬁc there. However, this often also includes a lot of trafﬁc unrelated to the VM.
VirtualBox provides an ability to capture network trafﬁc only on a speciﬁc VM’s network adapter. Refer to the network tracing article on the VirtualBox website2 for information on enabling this capture. The trace ﬁles created by VirtualBox are in .pcap format and can be easily analyzed with Wireshark.

12.1.3 The built-in VM debugger
VirtualBox includes a built-in VM debugger, which advanced users may ﬁnd useful. This debugger allows for examining and, to some extent, controlling the VM state.
Warning: Use the VM debugger at your own risk. There is no support for it, and the following documentation is only made available for advanced users with a very high level of familiarity with the x86/AMD64 machine instruction set, as well as detailed knowledge of the PC architecture. A degree of familiarity with the internals of the guest OS in question may also be very helpful.
The VM debugger is available in all regular production versions of VirtualBox, but it is disabled by default because the average user will have little use for it. There are two ways to access the debugger: 1 http://www.virtualbox.org/wiki/Core_dump.
2 http://www.virtualbox.org/wiki/Network_tips.

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• A debugger console window displayed alongside the VM
• Via the telnet protocol at port 5000
The debugger can be enabled in three ways:
• Start the VM directly using VirtualBox --startvm, with an additional --dbg, --debug, or --debug-command-line argument. See the VirtualBox usage help for details.
• Set the VBOX_GUI_DBG_ENABLED or VBOX_GUI_DBG_AUTO_SHOW environment variable to true before launching the VirtualBox process. Setting these variables (only their presence is checked) is effective even when the ﬁrst VirtualBox process is the VM selector window.
VMs subsequently launched from the selector will have the debugger enabled.
• Set the GUI/Dbg/Enabled extra data item to true before launching the VM. This can be set globally or on a per VM basis.
A new ’Debug’ menu entry will be added to the VirtualBox application. This menu allows the user to open the debugger console.
The VM debugger command syntax is loosely modeled on Microsoft and IBM debuggers used on DOS, OS/2 and Windows. Users familiar with symdeb, CodeView, or the OS/2 kernel debugger will ﬁnd the VirtualBox VM debugger familiar.
The most important command is help. This will print brief usage help for all debugger commands. The set of commands supported by the VM debugger changes frequently and the help command is always up-to-date.
A brief summary of frequently used commands follows:
• stop – stops the VM execution and enables single stepping
• g – continue VM execution
• t – single step an instruction
• rg/rh/r – print the guest/hypervisor/current registers
• kg/kh/k – print the guest/hypervisor/current call stack
• da/db/dw/dd/dq – print memory contents as ASCII/bytes/words/dwords/qwords
• u – unassemble memory
• dg – print the guest’s GDT
• di – print the guest’s IDT
• dl – print the guest’s LDT
• dt – print the guest’s TSS
• dp* – print the guest’s page table structures
• bp/br – set a normal/recompiler breakpoint
• bl – list breakpoints
• bc – clear a breakpoint
• writecore – writes a VM core ﬁle to disk, refer chapter 12.1.4, VM core format, page 229

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See the built-in help for other available commands.
The VM debugger supports symbolic debugging, although symbols for guest code are often not available. For Solaris guests, the detect command automatically determines the guest OS version and locates kernel symbols in guest’s memory. Symbolic debugging is then available.
For Linux guests, the detect commands also determines the guest OS version, but there are no symbols in the guest’s memory. Kernel symbols are available in the ﬁle /proc/kallsyms on Linux guests. This ﬁle must be copied to the host, for example using scp. The loadmap debugger command can be used to make the symbol information available to the VM debugger.
Note that the kallsyms ﬁle contains the symbols for the currently loaded modules; if the guest’s conﬁguration changes, the symbols will change as well and must be updated.
For all guests, a simple way to verify that the correct symbols are loaded is the k command.
The guest is normally idling and it should be clear from the symbolic information that the guest operating system’s idle loop is being executed.
Another group of debugger commands is the set of info commands. Running info help provides complete usage information. The information commands provide ad-hoc data pertinent to various emulated devices and aspects of the VMM. There is no general guideline for using the info commands, the right command to use depends entirely on the problem being investigated.
Some of the info commands are:
• cfgm – print a branch of the conﬁguration tree
• cpuid – display the guest CPUID leaves
• ioport – print registered I/O port ranges
• mmio – print registered MMIO ranges
• mode – print the current paging mode
• pit – print the i8254 PIT state
• pic – print the i8259A PIC state
• ohci/ehci/xhci – print a subset of the OHCI/EHCI/xHCI USB controller state
• pcnet0 – print the PCnet state
• vgatext – print the contents of the VGA framebuffer formatted as standard text mode
• timers – print all VM timers
The output of the info commands generally requires in-depth knowledge of the emulated device and/or VirtualBox VMM internals. However, when used properly, the information provided can be invaluable.

12.1.4 VM core format
VirtualBox uses the 64-bit ELF format for its VM core ﬁles created by VBoxManage debugvm; see chapter 8.35, VBoxManage debugvm, page 163. The VM core ﬁle contain the memory and
CPU dumps of the VM and can be useful for debugging your guest OS. The 64-bit ELF object format specﬁciation can be obtained here: http://downloads.openwatcom.org/ftp/devel/ docs/elf-64-gen.pdf. The overall layout of the VM core format is as follows:
[ ELF 64 Header]
[ Program Header, type PT_NOTE ]
-> offset to COREDESCRIPTOR
[ Program Header, type PT_LOAD ] - one for each contiguous physical memory range
-> Memory offset of range

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-> File offset
[ Note Header, type NT_VBOXCORE ]
[ COREDESCRIPTOR ]
-> Magic
-> VM core file version
-> VBox version
-> Number of vCPUs etc.
[ Note Header, type NT_VBOXCPU ] - one for each vCPU
[ vCPU 1 Note Header ]
[ DBGFCORECPU - vCPU 1 dump ]
[ Additional Notes + Data ] - currently unused
[ Memory dump ]

The memory descriptors contain physical addresses relative to the guest and not virtual addresses. Regions of memory such as MMIO regions are not included in the core ﬁle.
The relevant data structures and deﬁnitions can be found in the VirtualBox sources under the following header ﬁles: include/VBox/dbgfcorefmt.h, include/iprt/x86.h and src/VBox/Runtime/include/internal/ldrELFCommon.h. The VM core ﬁle can be inspected using elfdump and GNU readelf or other similar utilities.

12.2 General
12.2.1 Guest shows IDE/SATA errors for ﬁle-based images on slow host ﬁle system
Occasionally, some host ﬁle systems provide very poor writing performance and as a consequence cause the guest to time out IDE/SATA commands. This is normal behavior and should normally cause no real problems, as the guest should repeat commands that have timed out. However, some guests (e.g. some Linux versions) have severe problems if a write to an image ﬁle takes longer than about 15 seconds. Some ﬁle systems however require more than a minute to complete a single write, if the host cache contains a large amount of data that needs to be written.
The symptom for this problem is that the guest can no longer access its ﬁles during large write or copying operations, usually leading to an immediate hang of the guest.
In order to work around this problem (the true ﬁx is to use a faster ﬁle system that doesn’t exhibit such unacceptable write performance), it is possible to ﬂush the image ﬁle after a certain amount of data has been written. This interval is normally inﬁnite, but can be conﬁgured individually for each disk of a VM.
For IDE disks use the following command:
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/piix3ide/0/LUN#[x]/Config/FlushInterval" [b]

For SATA disks use the following command:
VBoxManage setextradata "VM name"
"VBoxInternal/Devices/ahci/0/LUN#[x]/Config/FlushInterval" [b]

The value [x] that selects the disk for IDE is 0 for the master device on the ﬁrst channel, 1 for the slave device on the ﬁrst channel, 2 for the master device on the second channel or 3 for the master device on the second channel. For SATA use values between 0 and 29. Only disks support this conﬁguration option; it must not be set for CD/DVD drives.
The unit of the interval [b] is the number of bytes written since the last ﬂush. The value for it must be selected so that the occasional long write delays do not occur. Since the proper ﬂush interval depends on the performance of the host and the host ﬁlesystem, ﬁnding the optimal value that makes the problem disappear requires some experimentation. Values between 1000000 and
10000000 (1 to 10 megabytes) are a good starting point. Decreasing the interval both decreases the probability of the problem and the write performance of the guest. Setting the value unnecessarily low will cost performance without providing any beneﬁts. An interval of 1 will cause a

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12 Troubleshooting ﬂush for each write operation and should solve the problem in any case, but has a severe write performance penalty.
Providing a value of 0 for [b] is treated as an inﬁnite ﬂush interval, effectively disabling this workaround. Removing the extra data key by specifying no value for [b] has the same effect.

12.2.2 Responding to guest IDE/SATA ﬂush requests
If desired, the virtual disk images can be ﬂushed when the guest issues the IDE FLUSH CACHE command. Normally these requests are ignored for improved performance. The parameters below are only accepted for disk drives. They must not be set for DVD drives.
To enable ﬂushing for IDE disks, issue the following command:
VBoxManage setextradata "VM name" "VBoxInternal/Devices/piix3ide/0/LUN#[x]/Config/IgnoreFlush" 0

The value [x] that selects the disk is 0 for the master device on the ﬁrst channel, 1 for the slave device on the ﬁrst channel, 2 for the master device on the second channel or 3 for the master device on the second channel.
To enable ﬂushing for SATA disks, issue the following command:
VBoxManage setextradata "VM name" "VBoxInternal/Devices/ahci/0/LUN#[x]/Config/IgnoreFlush" 0

The value [x] that selects the disk can be a value between 0 and 29.
Note that this doesn’t affect the ﬂushes performed according to the conﬁguration described in chapter 12.2.1, Guest shows IDE/SATA errors for ﬁle-based images on slow host ﬁle system, page
230. Restoring the default of ignoring ﬂush commands is possible by setting the value to 1 or by removing the key.

12.2.3 Performance variation with frequency boosting
Many newer multi-core processors support some form of frequency boosting, which means that if only one core is utilized, it can run faster (possibly 50% faster or even more) than the rated CPU frequency. This causes measured performance to vary somewhat as a function of the momentary overall system load. The exact behavior depends strongly on the speciﬁc processor model.
As a consequence, benchmarking on systems which utilize frequency boosting may produce unstable and non-repeatable results, especially if benchmark runs are short (on the order of seconds). To obtain stable results, benchmarks must be run over longer periods of time and with a constant system load apart from the VM being tested.

12.2.4 Frequency scaling effect on CPU usage
On some hardware platforms and operating systems, CPU frequency scaling may cause CPU usage reporting to be highly misleading. This happens in situations when the host CPU load is signiﬁcant but not heavy, such as 15-30% of the maximum.
Most operating systems determine CPU usage in terms of time spent, measuring for example how many nanoseconds the systems or a process was active within one second. However, in order to save energy, modern systems can signiﬁcantly scale down CPU speed when the system is not fully loaded. Naturally, when the CPU is running at (for example) one half of its maximum speed, the same number of instructions will take roughly twice as long to execute compared to running at full speed.
Depending on the speciﬁc hardware and host OS, this effect can very signiﬁcantly skew the
CPU usage reported by the OS; the reported CPU usage can be several times higher than what it would have been had the CPU been running at full speed. The effect can be observed both on the host OS and in a guest OS.

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12.2.5 Inaccurate Windows CPU usage reporting
CPU usage reporting tools which come with Windows (Task Manager, Resource Monitor) do not take the time spent processing hardware interrupts into account. If the interrupt load is heavy
(thousands of interrupts per second), CPU usage may be signiﬁcantly underreported.
This problem affects Windows as both host and guest OS. Sysinternals tools (e.g. Process
Explorer) do not suffer from this problem.

12.2.6 Poor performance caused by host power management
On some hardware platforms and operating systems, virtualization performance is negatively affected by host CPU power management. The symptoms may be choppy audio in the guest or erratic guest clock behavior.
Some of the problems may be caused by ﬁrmware and/or host operating system bugs. Therefore, updating the ﬁrmware and applying operating systems ﬁxes is recommended.
For optimal virtualization performance, the C1E power state support in the system’s BIOS should be disabled, if such a setting is available (not all systems support the C1E power state). On
Intel systems the Intel C State setting should be disabled. Disabling other power management settings may also improve performance. However, a balance between performance and power consumption must always be considered.

12.2.7 GUI: 2D Video Acceleration option is grayed out
To use 2D Video Acceleration within VirtualBox, your host’s video card should support certain
OpenGL extensions. On startup, VirtualBox checks for those extensions, and, if the test fails, this option is silently grayed out.
To ﬁnd out why it has failed, you can manually execute the following command:
VBoxTestOGL --log "log_file_name" --test 2D

It will list the required OpenGL extensions one by one and will show you which one failed the test. This usually means that you are running an outdated or misconﬁgured OpenGL driver on your host. It can also mean that your video chip is lacking required functionality.

12.3 Windows guests
12.3.1 Windows bluescreens after changing VM conﬁguration
Changing certain virtual machine settings can cause Windows guests to fail during start up with a bluescreen. This may happen if you change VM settings after installing Windows, or if you copy a disk image with an already installed Windows to a newly created VM which has settings that differ from the original machine.
This applies in particular to the following settings:
• The ACPI and I/O APIC settings should never be changed after installing Windows. Depending on the presence of these hardware features, the Windows installation program chooses special kernel and device driver versions and will fail to startup should these hardware features be removed. (Enabling them for a Windows VM which was installed without them does not cause any harm. However, Windows will not use these features in this case.)
• Changing the storage controller hardware will cause bootup failures as well. This might also apply to you if you copy a disk image from an older version of VirtualBox to a virtual machine created with a newer VirtualBox version; the default subtype of IDE controller hardware was changed from PIIX3 to PIIX4 with VirtualBox 2.2. Make sure these settings are identical.

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12.3.2 Windows 0x101 bluescreens with SMP enabled (IPI timeout)
If a VM is conﬁgured to have more than one processor (symmetrical multiprocessing, SMP), some conﬁgurations of Windows guests crash with an 0x101 error message, indicating a timeout for inter-processor interrupts (IPIs). These interrupts synchronize memory management between processors. According to Microsoft, this is due to a race condition in Windows. A hotﬁx is available.3 If this does not help, please reduce the number of virtual processors to 1.

12.3.3 Windows 2000 installation failures
When installing Windows 2000 guests, you might run into one of the following issues:
• Installation reboots, usually during component registration.
• Installation ﬁlls the whole hard disk with empty log ﬁles.
• Installation complains about a failure installing msgina.dll.
These problems are all caused by a bug in the hard disk driver of Windows 2000. After issuing a hard disk request, there is a race condition in the Windows driver code which leads to corruption if the operation completes too fast, i.e. the hardware interrupt from the IDE controller arrives too soon. With physical hardware, there is a guaranteed delay in most systems so the problem is usually hidden there (however it should be possible to reproduce it on physical hardware as well). In a virtual environment, it is possible for the operation to be done immediately (especially on very fast systems with multiple CPUs) and the interrupt is signaled sooner than on a physical system. The solution is to introduce an artiﬁcial delay before delivering such interrupts. This delay can be conﬁgured for a VM using the following command:
VBoxManage setextradata "VM name" "VBoxInternal/Devices/piix3ide/0/Config/IRQDelay" 1

This sets the delay to one millisecond. In case this doesn’t help, increase it to a value between
1 and 5 milliseconds. Please note that this slows down disk performance. After installation, you should be able to remove the key (or set it to 0).

12.3.4 How to record bluescreen information from Windows guests
When Windows guests run into a kernel crash, they display the infamous bluescreen. Depending on how Windows is conﬁgured, the information will remain on the screen until the machine is restarted or it will reboot automatically. During installation, Windows is usually conﬁgured to reboot automatically. With automatic reboots, there is no chance to record the bluescreen information which might be important for problem determination.
VirtualBox provides a method of halting a guest when it wants to perform a reset. In order to enable this feature, issue the following command:
VBoxManage setextradata "VM name" "VBoxInternal/PDM/HaltOnReset" 1

12.3.5 No networking in Windows Vista guests
With Windows Vista, Microsoft dropped support for the AMD PCNet card that VirtualBox used to provide as the default virtual network card before version 1.6.0. For Windows Vista guests,
VirtualBox now uses an Intel E1000 card by default.
If, for some reason, you still want to use the AMD card, you need to download the PCNet driver from the AMD website (available for 32-bit Windows only). You can transfer it into the virtual machine using a shared folder, see (see chapter 4.3, Shared folders, page 69).
3 See http://support.microsoft.com/kb/955076.

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12.3.6 Windows guests may cause a high CPU load
Several background applications of Windows guests, especially virus scanners, are known to increases the CPU load notably even if the guest appears to be idle. We recommend to deactivate virus scanners within virtualized guests if possible.

12.3.7 Long delays when accessing shared folders
The performance for accesses to shared folders from a Windows guest might be decreased due to delays during the resolution of the VirtualBox shared folders name service. To ﬁx these delays, add the following entries to the ﬁle \windows\system32\drivers\etc\lmhosts of the
Windows guest:
255.255.255.255
255.255.255.255

VBOXSVR #PRE
VBOXSRV #PRE

After doing this change, a reboot of the guest is required.

12.3.8 USB tablet coordinates wrong in Windows 98 guests
If a Windows 98 VM is conﬁgured to use the emulated USB tablet (absolute pointing device), the coordinate translation may be incorrect and the pointer is restricted to the upper left quarter of the guest’s screen.
The USB HID (Human Interface Device) drivers in Windows 98 are very old and do not handle tablets the same way all more recent operating systems do (Windows 2000 and later, Mac OS X,
Solaris). To work around the problem, issue the following command:
VBoxManage setextradata "VM name" "VBoxInternal/USB/HidMouse/0/Config/CoordShift" 0

To restore the default behavior, remove the key or set its value to 1.

12.3.9 Windows guests are removed from an Active Directory domain after restoring a snapshot
If a Windows guest is a member of an Active Directory domain and the snapshot feature of
VirtualBox is used, it could happen it loses this status after you restore an older snapshot.
The reason is the automatic machine password changing performed by Windows in regular intervals for security purposes. You can disable this feature by following the instruction of this http://support.microsoft.com/kb/154501 article from Microsoft.

12.3.10 Restoring d3d8.dll and d3d9.dll
VirtualBox Guest Additions for Windows prior to 4.1.8 did not properly back up the original d3d8.dll and d3d9.dll system ﬁles when selecting and installing the experimental Direct3D support. This process replaces both system ﬁles with ﬁles from the VirtualBox Guest Additions so that Direct3D calls can be handled correctly. Although this issue was ﬁxed with VirtualBox 4.1.8, there is no way the Windows Guest Additions installer can repair these ﬁles.
Corruption of these ﬁles has no implications in case 3D acceleration is enabled and basic Direct3D support is installed, that is, without WDDM (on Windows Vista or higher) or on older Windows systems like Windows XP. With the basic Direct3D support all Direct3D 8.0 and Direct3D
9.0 applications will utilize VirtualBox Direct3D ﬁles directly and thus will run as expected.
For WDDM Direct3D support however, the originally shipped d3d8.dll and d3d9.dll ﬁles are required in order to run Direct3D 8.0 and Direct3D 9.0 applications. As a result of the above mentioned system ﬁles corruption these applications will not work anymore. See below for a step-by-step guide for restoring the original d3d8.dll and d3d9.dll system ﬁles in case the

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VirtualBox Guest Additions installer warned about those incorrect ﬁles or when having trouble running Direct3D applications.
Note: Starting at Windows 7 the 3D desktop (aka Aero) uses DirectX 10 for rendering so that corrupted d3d8.dll and d3d9.dll system ﬁles will have no effect on the actual rendering. This is why such a detected ﬁle corruption is not considered as fatal for the basic Direct3D installation on all supported Windows guests, and for WDDM Direct3D installation on Windows
7 and later guests.
Extracting d3d8 and d3d9.dll from a Windows XP installation CD:
1. Download and install the latest version of 7-Zip File Manager http//www.7-zip.org
2. Browse into the installation CD for example E:\i386 (or amd64 for the 64-bit version)
3. Locate ﬁle d3d8.dl_ and d3d9.dl_, double click on it and Extract d3d8.dll and d3d9.dll
4. Reboot Windows in Safe mode
5. Copy extracted d3d8.dll and d3d9.dll to C:\Windows\system32 and C:\Windows\system32\dllcache
6. Reboot
Extracting d3d8 and d3d9.dll from Windows XP Service pack
1. 1, 3-6 Same as installation CD
2. Use ’Open inside’ to open WindowsXP-KB936929-SP3-x86.exe as archive and browse i386 directory. Extracting d3d8 and d3d9.dll from Vista/Windows7 installation CD or Service Pack iso
1. Download and install the latest version of 7-Zip File Manager http//www.7-zip.org
2. Browse into installation CD for example E:\sources
3. Locate ﬁle install.wim and double click it. After 7-Zip utility opens the ﬁle, you’ll get a few numbered folders. Each numeric subfolder represents a different version of Windows
(Starter, Home Basic, and so on)
4. After entering into the one of the numeric folders, browse into Windows\System32 (or
C:\Windows\SysWOW64 for the 64-bit version) directory locate d3d8.dll and d3d9.dll and extract 5. Copy extracted d3d8.dll and d3d9.dll to C:\Windows\system32 or C:\Windows\SysWOW64
(ﬁles from system32 should go to system32, from SysWOW64 to SysWOW64)
6. Reboot

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12.4 Linux and X11 guests
12.4.1 Linux guests may cause a high CPU load
Some Linux guests may cause a high CPU load even if the guest system appears to be idle.
This can be caused by a high timer frequency of the guest kernel. Some Linux distributions, for example Fedora, ship a Linux kernel conﬁgured for a timer frequency of 1000Hz. We recommend to recompile the guest kernel and to select a timer frequency of 100Hz.
Linux kernels shipped with Red Hat Enterprise Linux (RHEL) as of release 4.7 and 5.1 as well as kernels of related Linux distributions (for instance CentOS and Oracle Linux) support a kernel parameter divider=N. Hence, such kernels support a lower timer frequency without recompilation. We suggest to add the kernel parameter divider=10 to select a guest kernel timer frequency of 100Hz.

12.4.2 AMD Barcelona CPUs
Most Linux-based guests will fail with AMD Phenoms or Barcelona-level Opterons due to a bug in the Linux kernel. Enable the I/O-APIC to work around the problem (see chapter 3.4, System settings, page 47).

12.4.3 Buggy Linux 2.6 kernel versions
The following bugs in Linux kernels prevent them from executing correctly in VirtualBox, causing
VM boot crashes:
• The Linux kernel version 2.6.18 (and some 2.6.17 versions) introduced a race condition that can cause boot crashes in VirtualBox. Please use a kernel version 2.6.19 or later.
• With hardware virtualization and the I/O APIC enabled, kernels before 2.6.24-rc6 may panic on boot with the following message:
Kernel panic - not syncing: IO-APIC + timer doesn’t work! Boot with apic=debug and send a report. Then try booting with the ’noapic’ option

If you see this message, either disable hardware virtualization or the I/O APIC (see chapter
3.4, System settings, page 47), or upgrade the guest to a newer kernel.4

12.4.4 Shared clipboard, auto-resizing and seamless desktop in X11 guests Guest desktop services in guests running the X11 window system (Solaris, Linux and others) are provided by a guest service called VBoxClient, which runs under the ID of the user who started the desktop session and is automatically started using the following command lines
VBoxClient --clipboard
VBoxClient --display
VBoxClient --seamless

when your X11 user session is started if you are using a common desktop environment (Gnome,
KDE and others). If a particular desktop service is not working correctly, it is worth checking whether the process which should provide it is running.
The VBoxClient processes create ﬁles in the user’s home directory with names of the form
.vboxclient-*.pid when they are running in order to prevent a given service from being started twice. It can happen due to misconﬁguration that these ﬁles are created owned by root
4 See http://www.mail-archive.com/git-commits-head@vger.kernel.org/msg30813.html

kernel ﬁx.

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for details about the

12 Troubleshooting and not deleted when the services are stopped, which will prevent them from being started in future sessions. If the services cannot be started, you may wish to check whether these ﬁles still exist. 12.5 Solaris guests
12.5.1 Older Solaris 10 releases crash in 64-bit mode
Solaris 10 releases up to and including Solaris 10 8/07 (“S10U4”) incorrectly detect newer Intel processors produced since 2007. This problem leads to the 64-bit Solaris kernel crashing (and usually causing a triple fault) almost immediately during startup, in both virtualized and physical environments. The recommended solution is upgrading to at least Solaris 10 5/08 (“S10U5”). Alternative solutions include forcing Solaris to always boot the 32-bit kernel or applying a patch for bug
6574102 (while Solaris is using the 32-bit kernel).

12.5.2 Solaris 8 5/01 and earlier may crash on startup
Solaris 2.6, 7 and 8 releases up to and including Solaris 8 4/01 (“S8U4”) incorrectly set up
Machine Check Exception (MCE) MSRs on Pentium 4 and somene later Intel CPUs. The problem leads to the Solaris kernel crashing (and usually causing a triple fault) almost immediately during startup, in both virtualized and physical environments. Solaris 9 and later releases are not affected by this problem, and neither is Solaris 2.5.1 and earlier.
The recommended solution is upgrading to at least Solaris 8 7/01 (“S8U5”). Alternative solutions include applying a patch for bugs 4408508 and 4414557 (on an unaffected system).

12.6 FreeBSD guests
12.6.1 FreeBSD 10.0 may hang with xHCI
If xHCI (USB 3.0) emulation is enabled for FreeBSD 10.0 guests, the guest OS will hang. This is caused by the guest OS incorrectly handling systems where MSIs (Message Signaled Interrupts) are not used with the xHCI device.
The problem does not exist in earlier FreeBSD releases and was ﬁxed in FreeBSD 10.1.

12.7 Windows hosts
12.7.1 VBoxSVC out-of-process COM server issues
VirtualBox makes use of the Microsoft Component Object Model (COM) for inter- and intraprocess communication. This allows VirtualBox to share a common conﬁguration among different virtual machine processes and provide several user interface options based on a common architecture. All global status information and conﬁguration is maintained by the process
VBoxSVC.exe, which is an out-of-process COM server. Whenever a VirtualBox process is started, it requests access to the COM server and Windows automatically starts the process. Note that it should never be started by the end user.
When the last process disconnects from the COM server, it will terminate itself after some seconds. The VirtualBox conﬁguration (XML ﬁles) is maintained and owned by the COM server and the ﬁles are locked whenever the server runs.
In some cases - such as when a virtual machine is terminated unexpectedly - the COM server will not notice that the client is disconnected and stay active for a longer period (10 minutes or so) keeping the conﬁguration ﬁles locked. In other rare cases the COM server might experience

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12 Troubleshooting an internal error and subsequently other processes fail to initialize it. In these situations, it is recommended to use the Windows task manager to kill the process VBoxSVC.exe.

12.7.2 CD/DVD changes not recognized
In case you have assigned a physical CD/DVD drive to a guest and the guest does not notice when the medium changes, make sure that the Windows media change notiﬁcation (MCN) feature is not turned off. This is represented by the following key in the Windows registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Cdrom\Autorun

Certain applications may disable this key against Microsoft’s advice. If it is set to 0, change it to
1 and reboot your system. VirtualBox relies on Windows notifying it of media changes.

12.7.3 Sluggish response when using Microsoft RDP client
If connecting to a Virtual Machine via the Microsoft RDP client (called Remote Desktop Connection), there can be large delays between input (moving the mouse over a menu is the most obvious situation) and output. This is because this RDP client collects input for a certain time before sending it to the RDP server.
The interval can be decreased by setting a Windows registry key to smaller values than the default of 100. The key does not exist initially and must be of type DWORD. The unit for its values is milliseconds. Values around 20 are suitable for low-bandwidth connections between the
RDP client and server. Values around 4 can be used for a gigabit Ethernet connection. Generally values below 10 achieve a performance that is very close to that of the local input devices and screen of the host on which the Virtual Machine is running.
Depending whether the setting should be changed for an individual user or for the system, either HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client\Min Send Interval

or
HKEY_LOCAL_MACHINE\Software\Microsoft\Terminal Server Client\Min Send Interval

can be set appropriately.

12.7.4 Running an iSCSI initiator and target on a single system
Deadlocks can occur on a Windows host when attempting to access an iSCSI target running in a guest virtual machine with an iSCSI initiator (e.g. Microsoft iSCSI Initiator) that is running on the host. This is caused by a ﬂaw in the Windows cache manager component, and causes sluggish host system response for several minutes, followed by a “Delayed Write Failed” error message in the system tray or in a separate message window. The guest is blocked during that period and may show error messages or become unstable.
Setting the environment variable VBOX_DISABLE_HOST_DISK_CACHE to 1 will enable a workaround for this problem until Microsoft addresses the issue. For example, open a command prompt window and start VirtualBox like this: set VBOX_DISABLE_HOST_DISK_CACHE=1
VirtualBox

While this will decrease guest disk performance (especially writes), it does not affect the performance of other applications running on the host.

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12.7.5 Bridged networking adapters missing
If no bridged adapters show up in the “Networking” section of the VM settings, this typically means that the bridged networking driver was not installed properly on your host. This could be due to the following reasons:
• The maximum allowed ﬁlter count was reached on the host. In this case, the MSI log would mention the 0x8004a029 error code returned on NetFlt network component install:
VBoxNetCfgWinInstallComponent: Install failed, hr (0x8004a029)

You can try to increase the maximum ﬁlter count in the Windows registry at the following key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Network\MaxNumFilters

The maximum number allowed is 14. After a reboot, try to re-install VirtualBox.
• The INF cache is corrupt. In this case, the install log (%windir%\inf\setupapi.log on XP or %windir%\inf\setupapi.dev.log on Vista or later) would typically mention the failure to ﬁnd a suitable driver package for either the sun_VBoxNetFlt or sun_VBoxNetFltmp components. The solution then is to uninstall VirtualBox, remove the
INF cache (%windir%\inf\INFCACHE.1), reboot and try to re-install VirtualBox

12.7.6 Host-only networking adapters cannot be created
If host-only adapter cannot be created (either via the Manager or VBoxManage), then the INF cache is probably corrupt. In this case, the install log (%windir%\inf\setupapi.log on XP or %windir%\inf\setupapi.dev.log on Vista or later) would typically mention the failure to ﬁnd a suitable driver package for the sun_VBoxNetAdp component. Again, as with the bridged networking problem described above, the solution is to uninstall VirtualBox, remove the INF cache (%windir%\inf\INFCACHE.1), reboot and try to re-install VirtualBox.

12.8 Linux hosts
12.8.1 Linux kernel module refuses to load
If the VirtualBox kernel module (vboxdrv) refuses to load, i.e. you get an “Error inserting vboxdrv: Invalid argument”, check (as root) the output of the dmesg command to ﬁnd out why the load failed. Most probably the kernel disagrees with the version of the gcc used to compile the module. Make sure that you use the same compiler as used to build the kernel.

12.8.2 Linux host CD/DVD drive not found
If you have conﬁgured a virtual machine to use the host’s CD/DVD drive, but this does not appear to work, make sure that the current user has permission to access the corresponding Linux device ﬁle (/dev/hdc or /dev/scd0 or /dev/cdrom or similar). On most distributions, the user must be added to a corresponding group (usually called cdrom or cdrw).

12.8.3 Linux host CD/DVD drive not found (older distributions)
On older Linux distributions, if your CD/DVD device has a different name, VirtualBox may be unable to ﬁnd it. On older Linux hosts, VirtualBox performs the following steps to locate your
CD/DVD drives:
1. VirtualBox examines if the environment variable VBOX_CDROM is deﬁned (see below). If so,
VirtualBox omits all the following checks.

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2. VirtualBox tests if /dev/cdrom works.
3. In addition, VirtualBox checks if any CD/DVD drives are currently mounted by checking
/etc/mtab.
4. In addition, VirtualBox checks if any of the entries in /etc/fstab point to CD/DVD devices.
In other words, you can try to set VBOX_CDROM to contain a list of your CD/DVD devices, separated by colons, for example as follows: export VBOX_CDROM=’/dev/cdrom0:/dev/cdrom1’

On modern Linux distributions, VirtualBox uses the hardware abstraction layer (hal) to locate
CD and DVD hardware.

12.8.4 Linux host ﬂoppy not found
The previous instructions (for CD and DVD drives) apply accordingly to ﬂoppy disks, except that on older distributions VirtualBox tests for /dev/fd* devices by default, and this can be overridden with the VBOX_FLOPPY environment variable.

12.8.5 Strange guest IDE error messages when writing to CD/DVD
If the experimental CD/DVD writer support is enabled with an incorrect VirtualBox, host or guest conﬁguration, it is possible that any attempt to access the CD/DVD writer fails and simply results in guest kernel error messages (for Linux guests) or application error messages (for Windows guests). VirtualBox performs the usual consistency checks when a VM is powered up (in particular it aborts with an error message if the device for the CD/DVD writer is not writable by the user starting the VM), but it cannot detect all misconﬁgurations. The necessary host and guest
OS conﬁguration is not speciﬁc for VirtualBox, but a few frequent problems are listed here which occurred in connection with VirtualBox.
Special care must be taken to use the correct device. The conﬁgured host CD/DVD device ﬁle name (in most cases /dev/cdrom) must point to the device that allows writing to the CD/DVD unit. For CD/DVD writer units connected to a SCSI controller or to a IDE controller that interfaces to the Linux SCSI subsystem (common for some SATA controllers), this must refer to the
SCSI device node (e.g. /dev/scd0). Even for IDE CD/DVD writer units this must refer to the appropriate SCSI CD-ROM device node (e.g. /dev/scd0) if the ide-scsi kernel module is loaded.
This module is required for CD/DVD writer support with all Linux 2.4 kernels and some early
2.6 kernels. Many Linux distributions load this module whenever a CD/DVD writer is detected in the system, even if the kernel would support CD/DVD writers without the module. VirtualBox supports the use of IDE device ﬁles (e.g. /dev/hdc), provided the kernel supports this and the ide-scsi module is not loaded.
Similar rules (except that within the guest the CD/DVD writer is always an IDE device) apply to the guest conﬁguration. Since this setup is very common, it is likely that the default conﬁguration of the guest works as expected.

12.8.6 VBoxSVC IPC issues
On Linux, VirtualBox makes use of a custom version of Mozilla XPCOM (cross platform component object model) for inter- and intra-process communication (IPC). The process VBoxSVC serves as a communication hub between different VirtualBox processes and maintains the global conﬁguration, i.e. the XML database. When starting a VirtualBox component, the processes
VBoxSVC and VBoxXPCOMIPCD are started automatically. They are only accessible from the user account they are running under. VBoxSVC owns the VirtualBox conﬁguration database which normally resides in ~/.config/VirtualBox, or the appropriate conﬁguration directory for your

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12 Troubleshooting operating system. While it is running, the conﬁguration ﬁles are locked. Communication between the various VirtualBox components and VBoxSVC is performed through a local domain socket residing in /tmp/.vbox-<username>-ipc. In case there are communication problems
(i.e. a VirtualBox application cannot communicate with VBoxSVC), terminate the daemons and remove the local domain socket directory.

12.8.7 USB not working
If USB is not working on your Linux host, make sure that the current user is a member of the vboxusers group. On older hosts, you need to make sure that the user has permission to access the USB ﬁlesystem (usbfs), which VirtualBox relies on to retrieve valid information about your host’s USB devices. The rest of this section only applies to those older systems.
As usbfs is a virtual ﬁlesystem, a chmod on /proc/bus/usb has no effect. The permissions for usbfs can therefore only be changed by editing the /etc/fstab ﬁle.
For example, most Linux distributions have a user group called usb or similar, of which the current user must be a member. To give all users of that group access to usbfs, make sure the following line is present:
# 85 is the USB group none /proc/bus/usb

usbfs

devgid=85,devmode=664

0

0

Replace 85 with the group ID that matches your system (search /etc/group for “usb” or similar).
Alternatively, if you don’t mind the security hole, give all users access to USB by changing “664” to “666”.
The various distributions are very creative from which script the usbfs ﬁlesystem is mounted.
Sometimes the command is hidden in unexpected places. For SuSE 10.0 the mount command is part of the udev conﬁguration ﬁle /etc/udev/rules.d/50-udev.rules. As this distribution has no user group called usb, you may e.g. use the vboxusers group which was created by the VirtualBox installer. Since group numbers are allocated dynamically, the following example uses 85 as a placeholder. Modify the line containing (a linebreak has been inserted to improve readability) DEVPATH="/module/usbcore", ACTION=="add",
RUN+="/bin/mount -t usbfs usbfs /proc/bus/usb"

and add the necessary options (make sure that everything is in a single line):
DEVPATH="/module/usbcore", ACTION=="add",
RUN+="/bin/mount -t usbfs usbfs /proc/bus/usb -o devgid=85,devmode=664"

Debian Etch has the mount command in /etc/init.d/mountkernfs.sh. Since that distribution has no group usb, it is also the easiest solution to allow all members of the group vboxusers to access the USB subsystem. Modify the line domount usbfs usbdevfs /proc/bus/usb -onoexec,nosuid,nodev

so that it contains domount usbfs usbdevfs /proc/bus/usb -onoexec,nosuid,nodev,devgid=85,devmode=664

As usual, replace the 85 with the actual group number which should get access to USB devices.
Other distributions do similar operations in scripts stored in the /etc/init.d directory.

12.8.8 PAX/grsec kernels
Linux kernels including the grsec patch (see http://www.grsecurity.net/) and derivates have to disable PAX_MPROTECT for the VBox binaries to be able to start a VM. The reason is that VBox has to create executable code on anonymous memory.

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12.8.9 Linux kernel vmalloc pool exhausted
When running a large number of VMs with a lot of RAM on a Linux system (say 20 VMs with 1 GB of RAM each), additional VMs might fail to start with a kernel error saying that the vmalloc pool is exhausted and should be extended. The error message also tells you to specify vmalloc=256MB in your kernel parameter list. If adding this parameter to your GRUB or LILO conﬁguration makes the kernel fail to boot (with a weird error message such as “failed to mount the root partition”), then you have probably run into a memory conﬂict of your kernel and initial RAM disk. This can be solved by adding the following parameter to your GRUB conﬁguration: uppermem 524288

12.9 Solaris hosts
12.9.1 Cannot start VM, not enough contiguous memory
The ZFS ﬁle system is known to use nearly all available RAM as cache if the default system settings are not changed. This may lead to a heavy fragmentation of the host memory preventing
VirtualBox VMs from being started. We recommend to limit the ZFS cache by adding a line set zfs:zfs_arc_max = xxxx

to /etc/system where xxxx bytes is the amount of memory usable for the ZFS cache.

12.9.2 VM aborts with out of memory errors on Solaris 10 hosts
32-bit Solaris 10 hosts (bug 1225025) require swap space equal to, or greater than the host’s physical memory size. For example, 8 GB physical memory would require at least 8 GB swap.
This can be conﬁgured during a Solaris 10 install by choosing a ’custom install’ and changing the default partitions.
Note: This restriction applies only to 32-bit Solaris hosts, 64-bit hosts are not affected!
For existing Solaris 10 installs, an additional swap image needs to be mounted and used as swap. Hence if you have 1 GB swap and 8 GB of physical memory, you require to add 7 GB more swap. This can be done as follows:
For ZFS (as root user): zfs create -V 8gb /_<ZFS volume>_/swap swap -a /dev/zvol/dsk/_<ZFS volume>_/swap

To mount if after reboot, add the following line to /etc/vfstab:
/dev/zvol/dsk/_<ZFS volume>_/swap - - swap - no -

Alternatively, you could grow the existing swap using: zfs set volsize=8G rpool/swap

And reboot the system for the changes to take effect.
For UFS (as root user): mkfile 7g /path/to/swapfile.img swap -a /path/to/swapfile.img

To mount it after reboot, add the following line to /etc/vfstab:
/path/to/swap.img - - swap - no -

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13.1 General Security Principles
The following principles are fundamental to using any application securely.
Keep Software Up To Date One of the principles of good security practise is to keep all software versions and patches up to date. Activate the VirtualBox update notiﬁcation to get notiﬁed when a new VirtualBox release is available. When updating VirtualBox, do not forget to update the Guest Additions. Keep the host operating system as well as the guest operating system up to date.
Restrict Network Access to Critical Services Use proper means, for instance a ﬁrewall, to protect your computer and your guest(s) from accesses from the outside. Choosing the proper networking mode for VMs helps to separate host networking from the guest and vice versa.
Follow the Principle of Least Privilege The principle of least privilege states that users should be given the least amount of privilege necessary to perform their jobs. Always execute
VirtualBox as a regular user. We strongly discourage anyone from executing VirtualBox with system privileges.
Choose restrictive permissions when creating conﬁguration ﬁles, for instance when creating
/etc/default/virtualbox, see chapter 2.3.3.7, Automatic installation options, page 40. Mode
0600 would be preferred.
Monitor System Activity System security builds on three pillars: good security protocols, proper system conﬁguration and system monitoring. Auditing and reviewing audit records address the third requirement. Each component within a system has some degree of monitoring capability. Follow audit advice in this document and regularly monitor audit records.
Keep Up To Date on Latest Security Information Oracle continually improves its software and documentation. Check this note note yearly for revisions.

13.2 Secure Installation and Conﬁguration
13.2.1 Installation Overview
The VirtualBox base package should be downloaded only from a trusted source, for instance the ofﬁcial website http://www.virtualbox.org. The integrity of the package should be veriﬁed with the provided SHA256 checksum which can be found on the ofﬁcial website.
General VirtualBox installation instructions for the supported hosts can be found in chapter 2,
Installation details, page 33.
On Windows hosts, the installer allows for disabling USB support, support for bridged networking, support for host-only networking and the Python language bindings, see chapter 2.1,
Installing on Windows hosts, page 33. All these features are enabled by default but disabling some of them could be appropriate if the corresponding functionality is not required by any virtual machine. The Python language bindings are only required if the VirtualBox API is to be used by external Python applications. In particular USB support and support for the two networking modes require the installation of Windows kernel drivers on the host. Therefore disabling those

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13 Security guide selected features can not only be used to restrict the user to certain functionality but also to minimize the surface provided to a potential attacker.
The general case is to install the complete VirtualBox package. The installation must be done with system privileges. All VirtualBox binaries should be executed as a regular user and never as a privileged user.
The Oracle VM VirtualBox extension pack provides additional features and must be downloaded and installed separately, see chapter 1.5, Installing VirtualBox and extension packs, page
15. As for the base package, the SHA256 checksum of the extension pack should be veriﬁed. As the installation requires system privileges, VirtualBox will ask for the system password during the installation of the extension pack.

13.2.2 Post Installation Conﬁguration
Normally there is no post installation conﬁguration of VirtualBox components required. However, on Solaris and Linux hosts it is necessary to conﬁgure the proper permissions for users executing VMs and who should be able to access certain host resources. For instance, Linux users must be member of the vboxusers group to be able to pass USB devices to a guest. If a serial host interface should be accessed from a VM, the proper permissions must be granted to the user to be able to access that device. The same applies to other resources like raw partitions, DVD/CD drives and sound devices.

13.3 Security Features
This section outlines the speciﬁc security mechanisms offered by VirtualBox.

13.3.1 The Security Model
One property of virtual machine monitors (VMMs) like VirtualBox is to encapsulate a guest by executing it in a protected environment, a virtual machine, running as a user process on the host operating system. The guest cannot communicate directly with the hardware or other computers but only through the VMM. The VMM provides emulated physical resources and devices to the guest which are accessed by the guest operating system to perform the required tasks. The VM settings control the resources provided to the guest, for example the amount of guest memory or the number of guest processors, (see chapter 3.3, General settings, page 46) and the enabled features for that guest (for example remote control, certain screen settings and others).

13.3.2 Secure Conﬁguration of Virtual Machines
Several aspects of a virtual machine conﬁguration are subject to security considerations.
13.3.2.1 Networking
The default networking mode for VMs is NAT which means that the VM acts like a computer behind a router, see chapter 6.3, Network Address Translation (NAT), page 96. The guest is part of a private subnet belonging to this VM and the guest IP is not visible from the outside. This networking mode works without any additional setup and is sufﬁcient for many purposes.
If bridged networking is used, the VM acts like a computer inside the same network as the host, see chapter 6.5, Bridged networking, page 99. In this case, the guest has the same network access as the host and a ﬁrewall might be necessary to protect other computers on the subnet from a potential malicious guest as well as to protect the guest from a direct access from other computers. In some cases it is worth considering using a forwarding rule for a speciﬁc port in
NAT mode instead of using bridged networking.

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Some setups do not require a VM to be connected to the public network at all. Internal networking (see chapter 6.6, Internal networking, page 100) or host-only networking (see chapter
6.7, Host-only networking, page 101) are often sufﬁcient to connect VMs among each other or to connect VMs only with the host but not with the public network.
13.3.2.2 VRDP remote desktop authentication
When using the VirtualBox extension pack provided by Oracle for VRDP remote desktop support, you can optionally use various methods to conﬁgure RDP authentication. The “null” method is very insecure and should be avoided in a public network. See chapter 7.1.5, RDP authentication, page 109 for details.
13.3.2.3 Clipboard
The shared clipboard allows users to share data between the host and the guest. Enabling the clipboard in “Bidirectional” mode allows the guest to read and write the host clipboard. The
“Host to guest” mode and the “Guest to host” mode limit the access to one direction. If the guest is able to access the host clipboard it can also potentially access sensitive data from the host which is shared over the clipboard.
If the guest is able to read from and/or write to the host clipboard then a remote user connecting to the guest over the network will also gain this ability, which may not be desirable. As a consequence, the shared clipboard is disabled for new machines.
13.3.2.4 Shared folders
If any host folder is shared with the guest then a remote user connected to the guest over the network can access these ﬁles too as the folder sharing mechanism cannot be selectively disabled for remote users.
13.3.2.5 3D graphics acceleration
Enabling 3D graphics via the Guest Additions exposes the host to additional security risks; see chapter 4.5.1, Hardware 3D acceleration (OpenGL and Direct3D 8/9), page 73.
13.3.2.6 CD/DVD passthrough
Enabling CD/DVD passthrough allows the guest to perform advanced operations on the CD/DVD drive, see chapter 5.9, CD/DVD support, page 92. This could induce a security risk as a guest could overwrite data on a CD/DVD medium.
13.3.2.7 USB passthrough
Passing USB devices to the guest provides the guest full access to these devices, see chapter
3.10.1, USB settings, page 55. For instance, in addition to reading and writing the content of the partitions of an external USB disk the guest will be also able to read and write the partition table and hardware data of that disk.

13.3.3 Conﬁguring and Using Authentication
The following components of VirtualBox can use passwords for authentication:
• When using remote iSCSI storage and the storage server requires authentication, an initiator secret can optionally be supplied with the VBoxManage storageattach command. As long as no settings password is provided (command line option

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13 Security guide
--settingspwfile

, this secret is stored unencrypted in the machine conﬁguration and is therefore potentially readable on the host. See chapter 5.10, iSCSI servers, page 92 and chapter 8.18,
VBoxManage storageattach, page 144.
• When using the VirtualBox web service to control a VirtualBox host remotely, connections to the web service are authenticated in various ways. This is described in detail in the
VirtualBox Software Development Kit (SDK) reference; please see chapter 11, VirtualBox programming interfaces, page 225.

13.3.4 Potentially insecure operations
The following features of VirtualBox can present security problems:
• Enabling 3D graphics via the Guest Additions exposes the host to additional security risks; see chapter 4.5.1, Hardware 3D acceleration (OpenGL and Direct3D 8/9), page 73.
• When teleporting a machine, the data stream through which the machine’s memory contents are transferred from one host to another is not encrypted. A third party with access to the network through which the data is transferred could therefore intercept that data.
An SSH tunnel could be used to secure the connection between the two hosts. But when considering teleporting a VM over an untrusted network the ﬁrst question to answer is how both VMs can securely access the same virtual disk image(s) with a reasonable performance.
• When using the VirtualBox web service to control a VirtualBox host remotely, connections to the web service (through which the API calls are transferred via SOAP XML) are not encrypted, but use plain HTTP by default. This is a potential security risk! For details about the web service, please see chapter 11, VirtualBox programming interfaces, page 225.
The web services are not started by default. Please refer to chapter 9.21, Starting the
VirtualBox web service automatically, page 204 to ﬁnd out how to start this service and how to enable SSL/TLS support. It has to be started as a regular user and only the VMs of that user can be controlled. By default, the service binds to localhost preventing any remote connection. • Trafﬁc sent over a UDP Tunnel network attachment is not encrypted. You can either encrypt it on the host network level (with IPsec), or use encrypted protocols in the guest network
(such as SSH). The security properties are similar to bridged Ethernet.
• Because of shortcomings in older Windows versions, using VirtualBox on Windows versions older than Vista with Service Pack 1 is not recommended.

13.3.5 Encryption
The following components of VirtualBox use encryption to protect sensitive data:
• When using the VirtualBox extension pack provided by Oracle for VRDP remote desktop support, RDP data can optionally be encrypted. See chapter 7.1.6, RDP encryption, page
110 for details. Only the Enhanced RDP Security method (RDP5.2) with TLS protocol provides a secure connection. Standard RDP Security (RDP4 and RDP5.1) is vulnerable to a man-in-the-middle attack.

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14.1 Experimental Features
Some VirtualBox features are labeled as experimental. Such features are provided on an “as-is” basis and are not formally supported. However, feedback and suggestions about such features are welcome. A comprehensive list of experimental features follows:
• WDDM Direct3D video driver for Windows guests
• Hardware 3D acceleration support for Windows, Linux, and Solaris guests
• Hardware 2D video playback acceleration support for Windows guests
• PCI pass-through (Linux hosts only)
• Mac OS X guests (Mac hosts only)
• ICH9 chipset emulation
• EFI ﬁrmware
• Host CD/DVD drive pass-through
• Support of iSCSI via internal networking
• Synthetic CPU reporting

14.2 Known Issues
The following section describes known problems with VirtualBox 5.0.0. Unless marked otherwise, these issues are planned to be ﬁxed in later releases.
• The following Guest SMP (multiprocessor) limitations exist:
– Poor performance with 32-bit guests on AMD CPUs. This affects mainly Windows and Solaris guests, but possibly also some Linux kernel revisions. Partially solved in
3.0.6 for 32 bits Windows NT, 2000, XP and 2003 guests. Requires 3.0.6 or higher
Guest Additions to be installed.
– Poor performance with 32-bit guests on certain Intel CPU models that do not include virtual APIC hardware optimization support. This affects mainly Windows and Solaris guests, but possibly also some Linux kernel revisions. Partially solved in 3.0.12 for
32 bits Windows NT, 2000, XP and 2003 guests. Requires 3.0.12 or higher Guest
Additions to be installed.
• NX (no execute, data execution prevention) only works for guests running on 64-bit hosts or guests running on 32-bit hosts with PAE enabled and requires that hardware virtualization be enabled.

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• For basic Direct3D support in Windows guests to work, the Guest Additions must be installed in Windows “safe mode”. Press F8 when the Windows guest is booting and select
“Safe mode”, then install the Guest Additions. Otherwise Windows’ ﬁle protection mechanism will interfere with the replacement DLLs installed by VirtualBox and keep restoring the original Windows system DLLs.
Note: This does not apply to the experimental WDDM Direct3D video driver available for Vista and Windows 7 guests shipped with VirtualBox 4.1.

• Guest control. On Windows guests, a process lauched via the guest control execute support will not be able to display a graphical user interface unless the user account under which it is running is currently logged in and has a desktop session.
Also, to use accounts without or with an empty password, the guest’s group policy must be changed. To do so, open the group policy editor on the command line by typing gpedit.msc, open the key Computer Conﬁguration\Windows Settings\Security Settings\Local Policies\Security Options and change the value of Accounts: Limit local account use of blank passwords to console logon only to Disabled.
• Compacting virtual disk images is limited to VDI ﬁles. The VBoxManage modifyhd
--compact command is currently only implemented for VDI ﬁles. At the moment the only way to optimize the size of a virtual disk images in other formats (VMDK, VHD) is to clone the image and then use the cloned image in the VM conﬁguration.
• OVF import/export:
– OVF localization (multiple languages in one OVF ﬁle) is not yet supported.
– Some OVF sections like StartupSection, DeploymentOptionSection and InstallSection are ignored.
– OVF environment documents, including their property sections and appliance conﬁguration with ISO images, are not yet supported.
– Remote ﬁles via HTTP or other mechanisms are not yet supported.
• Neither scale mode nor seamless mode work correctly with guests using OpenGL 3D features (such as with compiz-enabled window managers).
• The RDP server in the VirtualBox extension pack supports only audio streams in format
22.05kHz stereo 16 bit. If the RDP client requests any other audio format there will be no audio. • Preserving the aspect ratio in scale mode works only on Windows hosts and on Mac OS X hosts. • On Mac OS X hosts, the following features are not yet implemented:
– Numlock emulation
– CPU frequency metric
– Memory ballooning
• Mac OS X guests:
– Mac OS X guests can only run on a certain host hardware. For details about license and host hardware limitations, please see chapter 3.1.1, Mac OS X guests, page 44 and check the Apple software license conditions.
– VirtualBox does not provide Guest Additions for Mac OS X at this time.

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– The graphics resolution currently defaults to 1024x768 as Mac OS X falls back to the built-in EFI display support. See chapter 3.12.1, Video modes in EFI, page 57 for more information on how to change EFI video modes.
– Mac OS X guests only work with one CPU assigned to the VM. Support for SMP will be provided in a future release.
– Depending on your system and version of Mac OS X, you might experience guest hangs after some time. This can be ﬁxed by turning off energy saving (set timeout to
“Never”) in the system preferences.
– By default, the VirtualBox EFI enables debug output of the Mac OS X kernel to help you diagnose boot problems. Note that there is a lot of output and not all errors are fatal (they would also show on your physical Mac). You can turn off these messages by issuing this command:
VBoxManage setextradata "VM name" "VBoxInternal2/EfiBootArgs" "

"

To revert to the previous behavior, use:
VBoxManage setextradata "VM name" "VBoxInternal2/EfiBootArgs" ""

– It is currently not possible to start a Mac OS X guest in safe mode by specifying “-x” option in “VBoxInternal2/EﬁBootArgs” extradata.
• Solaris hosts:
– There is no support for USB devices connected to Solaris 10 hosts.
– USB support on Solaris hosts requires Solaris 11 version snv_124 or higher. Webcams and other isochronous devices are known to have poor performance.
– Host Webcam passthrough is restricted to 640x480 frames at 20 frames per second due to limitations in the Solaris V4L2 API. This may be addressed in a future Solaris release. – No ACPI information (battery status, power source) is reported to the guest.
– No support for using wireless adapters with bridged networking.
– Crossbow-based bridged networking on Solaris 11 hosts does not work directly with aggregate links. However, you can manually create a VNIC (using dladm) over the aggregate link and use that with a VM. This limitation does not exist in Solaris 11u1 build 17 and newer.
• Guest Additions of version 4.1, 4.1.2 and 4.1.4 for Windows Thus VirtualBox WDDM
Video driver may be installed and kept in guest system if Guest additions uninstallation is performed. This is caused by a bug in Guest Additions uninstaller.
Note: This does not apply to Guest Additions update, i.e. installing a one version of
Guest Additions on top of another works correctly.
To solve this problem, one should uninstall the VirtualBox WDDM Video driver manually. To do that open Device Manager, and check whether the Display Adapter is named
“VirtualBox Graphics Adapter ..“. If no - there is nothing to be done. If yes - right-click the
VirtualBox Graphics Adapter in Device Manager, select “Uninstall”, check “Delete the driver software for this device” and click “OK”. Once uninstallation is done - in Device Manager go to menu “Action” and select “Scan for hardware changes” to make the propper (Windows default) driver be picked up for the Graphics adapter.
• Neither virtio nor Intel PRO/1000 drivers for Windows XP guests support segmentation ofﬂoading. Therefore Windows XP guests have slower transmission rates comparing to other guest types. Refer to MS Knowledge base article 842264 for additional information.

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14 Known limitations
• Guest Additions for OS/2. Shared folders are not yet supported with OS/2 guests. In addition, seamless windows and automatic guest resizing will probably never be implemented due to inherent limitations of the OS/2 graphics system.

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15 Change log
This section summarizes the changes between VirtualBox versions. Note that this change log is not exhaustive; not all changes are listed.
VirtualBox version numbers consist of three numbers separated by dots where the ﬁrst and second number represent the major version and the 3rd number the minor version. Minor version numbers of ofﬁcial releases are always even. An odd minor version number represents an internal development or test build. In addition, each build contains a revision number.

15.1 Version 5.0.0 (2015-07-09)
This is a major update. The following major new features were added:
• Paravirtualization support for Windows and Linux guests to improve time-keeping accuracy and performance (see chapter 10.4, Paravirtualization providers, page 220)
• Make more instruction set extensions available to the guest when running with hardwareassisted virtualization and nested paging. Among others this includes: SSE 4.1, SSE4.2,
AVX, AVX-2, AES-NI, POPCNT, RDRAND and RDSEED
• xHCI Controller to support USB 3 devices (see chapter 3.10.1, USB settings, page 55)
• Drag and drop support (bidirectional) for Windows, Linux and Solaris guests
• Disk image encryption (see chapter 9.31, Encryption of disk images, page 212)
• VMs can now be started in separate mode. The VM process is started headless while the frontend runs as a separate process which can be terminated without stopping the VM.
• GUI: VM guest-content scaling support (including 3D acceleration)
• GUI: New User Interface settings page for customizing status-bar, menu-bar and guestcontent scaling
• GUI: New Encryption settings tab for customizing encryption options for disk images
• GUI: HiDPI support including application icons and optional unscaled HiDPI output on Mac
OS X (including 3D acceleration)
• GUI: Hotplugging support for SATA disks
• New, modular audio architecture for providing a better abstraction of the host audio backends
• Support for the NDIS6 networking framework on Windows (default on Vista and later)
In addition, the following items were ﬁxed and/or added:
• VMM: improved timing on Solaris hosts with older VT-x hosts without preemption timers
• VMM: further improvements for TSC frequency measurements and guest timekeeping
• VMM: debug facility now includes the guest CPU’s FPU/SSE/extended state in the core dump 251

15 Change log
• VMM: ﬁxed a hang under rare conditions on 32-bit hosts
• VMM: several ﬁxes
• GUI: improved HID LEDs synchronization for Mac and Windows hosts. The physical LEDs state now restored together with the VM state.
• GUI: take the guest screen aspect ratio into account for the preview window
• GUI: provide direct access to storage media in the VM selector
• GUI: allow to save the VM state from the selector even if the VM is already paused
• VBoxManage: when exporting an appliance, support the suppression of MAC addresses, which means they will be always recreated on import, avoiding duplicate MAC addresses for VMs which are imported several times
• VBoxManage: now supports renaming storage controllers and USB controllers
• Guest Control: major overhaul, for example ﬁxing wrong parameter quoting (bug #13157)
• USB: added USB trafﬁc capturing (see chapter 9.29, Capturing USB trafﬁc for selected devices, page 212)
• Made resizing X11 guests work more reliably
• API: block the removal of the current snapshot if it has child snapshots (only relevant for
VMs without snapshottable hard disks, their presence always prevented removal), which resulted in VM conﬁg corruption
• API: mark VM conﬁgs with snapshots but without current snapshot as inaccessible, as this combination is nonsense
• API: ﬁx information for some automatically generated events (only with XPCOM, Windows host was not affected), which caused errors when getting some of the attributes over the webservice (bug #12379)
• API: ﬁx crashes in Java API clients using the XPCOM binding, happened with output parameters only (bug #11232)
• API: a number of settings (e.g. network settings) can now also be changed when the VM is in saved state
• API: ﬁxed incorrect resuming of VMs on host-resume unless they were previously paused due to a host-suspend
• API: don’t lose the saved state and “current state changed” ﬂag during cloning of a VM
• API: OS type description consistency ﬁx (bug #14162)
• VBoxSVC: don’t keep the support driver permanently open
• Main/Properties: properly drop transient guest properties when the VM is powered off
• VRDP: ﬁxed a couple of races which may cause a crash during VM poweroff
• ExtPack: don’t fail if the TMP directory contains non-latin1 characters (bug #14159)
• 3D: ﬁx potential race in which might cause a crash on VM termination
• 3D: ﬁxed a possible memory leak in the host service
• Serial: new TCP/IP backend (see chapter 3.9, Serial ports, page 53)

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15 Change log
• Storage: added USB mass storage device class (see chapter 5.1, Hard disk controllers: IDE,
SATA (AHCI), SCSI, SAS, USB MSC, page 81)
• Storage: added vbox-img standalone tool for direct manipulation of virtual hard disk images without VBoxManage
• Storage: ﬁxed crash as a result of I/O errors in certain conditions (bug #13105)
• NAT: ﬁxed several potential crashes
• NAT: don’t forcibly reset/drop all connections when the link goes down
• Netsniffer: properly handle changing of the trace ﬁle name at VM runtime
• Audio: ﬁxed audio output and input when changing the default audio device more than once on OS X
• Audio: ﬁxed audio input on OS X under certain circumstances
• ICH9: ﬁxed the interrupt disable logic for MSI interrupts; should ﬁx old Linux guests with
AHCI
• USB: improve playback with USB sound devices attached to the emulated OHCI controller
• Audio: provide Linux guests a different AC97 audio codec type so Linux ALSA does not mis-detect the link speed (default for new VMs)
• BIOS: ﬁx for booting from SCSI CD/DVD media
• BIOS: ﬁx for reads partially beyond end of disk (bug #14021)
• VRDP: ﬁxed listening for IPv6 on some systems (bug #14038)
• rdesktop-vrdp: upgraded to version 1.8.3
• Linux hosts: ﬁxed a bug which made the netﬁlter driver ignore certain events (bug
#12264)
• Mac OS X hosts: El Capitan ﬁxes
• Mac OS X hosts: ﬁxed a bug which might trigger a host kernel panic if a VM is started and another hypervisor is active
• Solaris hosts: Solaris 12 installer ﬁx
• Guest Additions: added a heartbeat service (see chapter 9.30, Conﬁguring the heartbeat service, page 212)
• Linux hosts / guests: support for Linux distributions using systemd without sysv emulation
(e.g. ArchLinux)
• Windows Additions/WDDM: improved video memory utilization and allow more/bigger guest screens with large resolutions (including HiDPI)
• Linux Additions: added -s parameter to mount.vboxsf to be sloppy with invalid parameters
• X11 Additions: ﬁxed wrong DPI value (bug #14151)
• Mac OS X guests: limit the CPU family for legacy guests
• Solaris Additions: added quiesce support to co-operate with Solaris’ fast-reboot feature

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15 Change log

15.2 Version 4.3.28 (2015-05-13)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: ﬁxed a Guru Meditation when rebooting certain guests (for example Solaris doing fast reboot) by ﬁxing the implementation for INIT IPI
• VMM: added some information for diagnosing rare VERR_VMX_INVALID_VMXON_PTR
Guru Meditations (VT-x only)
• GUI: HID LEDs sync: prevent synchronization if VM window has no focus (Windows and
Mac OS X hosts only)
• GUI: ﬁxed drag and drop moving the cursor between guest screens on certain hosts
• 3D: ﬁxed a crash on restoring the VM state on X11 hosts (bug #12737)
• 3D: ﬁxed a crash on restoring the VM state
• 3D: ﬁxed a crash on Linux guest shutdown (bug #12772)
• VRDP: ﬁxed incompatibility with rdesktop 1.8.3
• VRDP: ﬁxed listening for IPv6 on some systems (bug #14038)
• Storage: don’t crash if creating an asynchronous I/O context fails (e.g. when starting many
VMs) and show a proper error message
• Floppy: several ﬁxes
• Audio: improved the behavior of the volume control for the HD audio device emulation
• USB: increase the number of supported drivers from 3 to 5 (Windows hosts only)
• PS/2 keyboard: synchronize the LED state on VM restore (Windows and Mac OS X hosts only) • NAT Network: when running multiple NAT networks with multiple VMs, only stop the respective services when stopping VMs (bug #14090)
• NAT: don’t kill UDP bindings on ICMP errors (bug #13475)
• NAT: bandwidth limit now works properly with NAT (bug #11485)
• BIOS: ﬁxed the returned size value of the VBE 2.0 PMI function 0Ah (4.2.0 regression; bug
#14096)
• Guest Control: ﬁxed parameter quoting in Windows guests (bug #13157)
• Webcam passthrough improvements for Linux (V4L2) hosts to support more webcam models
• API: don’t fail starting a VM with VBOX_E_INVALID_OBJECT_STATE under certain conditions (bug #13617)
• API: be more verbose on VBOX_E_INVALID_OBJECT_STATE if a medium is attached to a running VM (bug #13560)
• API: ﬁxed a bug which could result in losing certain screen resize events with multi-monitor guests • rdesktop-vrdp: ﬁxed path to the keymaps (bug #12066)

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15 Change log
• rdesktop-vrdp: switch to version 1.8.3
• Windows hosts: more hardening ﬁxes (e.g. bugs #14051, #14052)
• Linux hosts: another ﬁx for activated SMAP on Linux 3.19 and newer (Broadwell and later; bug #13961)
• Linux hosts: Linux 4.1 compile ﬁx (bug #14081)
• Solaris hosts: ﬁxed using of VNIC templates with Crossbow based bridged networking to be compatible with vanity interface names
• Mac OS X hosts: ﬁxed crash during VM termination under rare circumstances
• Windows Additions/WDDM: improved video memory utilization and allow more/bigger guest screens with large resolutions (including HiDPI)
• X11 Additions: prevent ﬂickering when updating mouse cursor
• Solaris Additions: ﬁxed incorrect usage of ’prtconf’ while installing Guest Additions (Solaris
10 only)

15.3 Version 4.3.26 (2015-03-16)
This is a maintenance release. The following items were ﬁxed and/or added:
• GUI: in the snapshots pane, protect the age of snapshots against wrong host time (bug
#13955)
• NAT Network: ﬁxed a bug which prevented to propagate any DNS name server / domain / search string information to the NAT network (4.3.24 regression; bugs #13915, #13918)
• NAT Network: don’t delay the shutdown of VBoxSVC on Windows hosts
• Mouse support: the mouse could not be moved under rare conditions if no Guest Additions are installed (4.3.24 regression; bug #13935)
• Storage: if the guest ejects a virtual CD/DVD medium, make the change permanent (bugs
#9858, #12885)
• VGA: made saving secondary screen sizes possible in X11 guests
• SDK: ﬁxed the VirtualBox.tlb ﬁle (4.3.20 regression; bug #13943)
• rdesktop-vrdp: make it work with USB devices again (4.3.14 regression; bug #13901)
• USB: ﬁxed a possible BSOD on Windows hosts under rare conditions
• iPXE: enable the HTTP download protocol on non-Linux hosts (bug #13628)
• Mac OS X hosts: don’t panic on hosts with activated SMAP (Broadwell and later; bug
#13951)
• Linux hosts: don’t crash Linux 4.0 hosts (bug #13835)

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15 Change log

15.4 Version 4.3.24 (2015-03-02)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: emulation ﬁx for the ENTER instruction under certain conditions; ﬁxes Solaris 10 guests (VT-x without unrestricted guest execution)
• VMM: ﬁx for handling NMIs on Linux hosts with X2APIC enabled
• NAT/NAT Network: ﬁx connection drops when the host’s DHCP lease was renewed (4.3.22 regression; Windows hosts only; bug #13839)
• NAT: don’t crash on an empty domain list when switching the DNS host conﬁguration
(4.3.22 regression; Mac OS X hosts only; bug #13874)
• PXE: re-enable it on Windows hosts (4.3.22 regression; Windows hosts only; bug #13842)
• Shared Folders: ﬁxed a problem with Windows guests (4.3.22 regression; bug #13786)
• Audio: improved record quality when using the DirectSound audio backend
• VBoxManage: when executing the controlvm command take care that the corresponding
VM runtime changes are saved permanently (bug #13892)
• Windows Installer: properly install the 32-bit version of VBoxRes.dll on 32-bit hosts (bug
#13876)
• Linux hosts / guests: Linux 4.0 ﬁxes (bug #13835)
• OS/2 Additions: ﬁxed mouse integration (4.3.22 regression; bug #13825)

15.5 Version 4.3.22 (2015-02-12)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: reﬁned measurement of TSC frequency on the host, improves timekeeping for guests
• VMM: decreased CPU load resulting from guest MMIO writes to the virtual APIC
• VMM: ﬁxed interception of debug exceptions, observed while using the dbx debugger on
Solaris guests (VT-x only)
• GUI: 3D overlay window positioning code improved, ﬁxed potential misplacement of 3D accelerated guest graphics content
• GUI: ﬁxed accident SSL authentication failures during update check on Windows hosts
(bug #12969)
• GUI: never send the “ACPI power” keyboard scancode to the guest, we have the ACPI power button for that
• GUI: was unable to properly restore seamless mode VM from snapshot/saved-state under some circumstances
• VBoxHeadless: don’t crash if 3D is enabled in the VM settings (bug #10250)
• ATA: ﬁxed several passthrough issues (bugs #12310, #1360)
• Audio: ﬁxed DirectSound failure when the the host has no audio input device (Windows hosts only; bug #9205)

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15 Change log
• SB16: ﬁxed compatibility issue (bug #13769)
• Storage: ﬁxed broken CD/DVD passthrough when using the IDE controller (bug #12310)
• NAT: new ping proxy for Windows hosts (bug #11871)
• NAT: Properly report outbound connect(2) failures to guest with TCP RST or ICMP (bug
#10525)
• NAT Network: no need for frequent wakeups in VBoxNetDHCP and VBoxNetNAT (bug
#11681)
• Host-only adapter: prevent Windows from creating an “Unidentiﬁed network” (bug
#9688)
• Bridged Networking: don’t leak host-to-guest trafﬁc to the wireless network when bridging to a wireless interface (bug #13714)
• Main: ﬁxed a possible race when changing the medium leading to a deadlock under rare conditions (bug #13722)
• VBoxManage: ﬁxed return code if starting a VM failed (bug #13773)
• Settings: on Windows host, do not use environment variable HOME at all, the settings location is derived from the user proﬁle directory (bug #7689)
• API: ﬁxed 2 deadlock opportunities related to medium handling (bugs #13789, #13801, thank you Alexander Urakov)
• API: ﬁxed bug in XPCOM which created too few worker threads, sporadically resulting in a deadlock (bug #13802, thank you Alexander Urakov)
• SDK: ﬁxed a garbage collection leak in the Python VirtualBox webservice API binding (bug
#13817)
• Linux hosts: ﬁxes for activated SMAP (Broadwell and later, bug #13820)
• X11 guests: prevent unwanted hiding of guest screens on multi-monitor guests (bug
#13287)
• X11 guests: added support for X.Org Server 1.17
• X11 Additions: ﬁxed a memory leak in VBoxService if libdbus is available but dbus-daemon isn’t running (bug #13770)
• Windows Additions: prevent VBox WDDM driver from loading if host reports weak OpenGL capabilities. 3D content now can be shown over Remote Desktop connection.
• Winodws Additions: some ﬁxes for recent Windows 10 Previews
• Linux Additions: ﬁxed a compatibility issue with 64-bit Linux 2.4 kernels
• Linux Additions: ﬁxed a potential use-after-free when unloading the VBoxGuest module
• Linux Additions: Linux 3.19 ﬁxes (bug #13741)

257

15 Change log

15.6 Version 4.3.20 (2014-11-21)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: ﬁxed reboot hang of 32-bit Windows SMP guests (bugs #13319, #13462)
• VMM: proper Math Fault handling with certain legacy guests (bug #9042, AMD hosts)
• VMM: ﬁxed a Guru Meditation VINF_EM_TRIPLE_FAULT on older CPUs that don’t support
MSR-bitmaps (VT-x only; bugs #13034, #13125, #13311, #13425, #13426, #13463,
#13585)
• GUI: ﬁx 3D overlay window reparenting issue when VM goes to fullscreen mode on X11 hosts • GUI: ﬁx occasional loss of focus in full-screen mode on X11 host systems (4.3.16 regression)
• GUI: Mac OS X: wizards should have Cancel button (bug #12541)
• GUI: added a global option to prevent automatic raising of the new window by mouse move with multi-screen guests (bug #8878)
• API: accept remote display port 0 as the default RDP port (bug #8534)
• VBoxManage: ﬁxed crash when executing showvminfo command under certain circumstances (bug #13190)
• ACPI: ﬁxed occassional Guru Meditations in ACPI timer code (4.3.18 regression; bug
#13521)
• EFI: improved performance of IDE disk access
• EFI: ﬁxed a bug in the EFI video driver which prevented Windows to boot in UEFI mode
(bug #12022)
• EFI: properly announce the amount of RAM for big VMs (bugs #11103 and #13211)
• Storage: ﬁxed a crash under certain cicrumstances when a medium was ejected from a drive attached to the SATA controller without inserting a new medium before pausing or closing the VM (4.3.16 regression)
• Storage: ﬁxed an interrupt acknowledge issue causing hanging guests or slower I/O (4.3.18 regression) • Storage: ﬁxed broken resume after the VM was suspended due to a full disk if host I/O caching is used
• Storage: ﬁxed a Guru Meditation under certain conditions when using the DevLsiLogic controller with VMs running in raw mode (4.3 regression; bugs #12254, #12655, #12709,
#12774, #12886)
• Guest Control: ﬁxed a bug which might lead to a crash during recursive copy
• SDK: Java COM bindings ﬁxes
• iPXE: enable the HTTP download protocol (bug #13628)
• Runtime: do not use a ﬁxed stack size creating temporary threads during initialization (bug
#13038)
• Windows hosts: ﬁxed more startup problems on certain Windows hosts due to conﬂicts with anti-virus software; better error reporting (4.3.14 regression; bug #13187)

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15 Change log
• Windows hosts: ﬁxed DirectSound host audio failure under certain conditions (bug
#13418)
• Windows hosts: ﬁxed additional cases of 4.3.14 regression whereby AltGr stopped working for some people (bug #13216)
• Windows Additions: preserve guest monitor layout when resizing Windows 7 or newer guests • Linux Additions: Linux 3.18 compile ﬁxes (bug #13515)

15.7 Version 4.3.18 (2014-10-10)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: ﬁxed a potential misbehavior after restoring the A20 state from a saved state
• GUI: ﬁxed full-screen mode mini-toolbar related regressions for different platforms and window managers (bug #13369)
• GUI: X11: ﬁxed full-screen mode Unity panels quirk caused by mini-toolbar code changes in last release (bug #13365)
• GUI: X11: added possibility to use legacy full-screen mode as the new one can cause multiscreen issues under Unity, see chapter 9.20.12, Requesting legacy full-screen mode, page 204
(bug #13365)
• GUI: Mac OS X: ﬁxed full-screen mode artifact causing black screen when 3D acceleration was enabled on 10.10 Yosemite hosts (bug #13448)
• GUI: Mac OS X: ﬁxed regression in user-space swiping from/to VBox in full-screen mode
• GUI: Mac OS X: ﬁxed issue with switching to VBox in full-screen mode through Alt+Tab and Mission Control
• Storage: ﬁxed data corruption when resizing huge VHD images under certain circumstances (bug #11960)
• Storage: ﬁxed a rare hang during startup when the BIOS enumerates the storage devices attached to the SATA controller
• Storage: follow the spec with AHCI interrupt acknowledge (bug #13474)
• Storage: ﬁxed broken iSCSI authentication (4.3.14 regression; bugs #13386, #13435)
• NAT Network: properly parse port forwarding rules to allow UDP rules
• USB: ﬁxed a crash on Linux hosts with older Linux kernels (bug #13400) and several other ﬁxes • ACPI: ﬁxed ACPI timer anomalies (bug #12076)
• Guest Control: ﬁxed a memory leak (bug #13434)
• Main: when removing a VM, do also remove the VBoxStartup.log ﬁle which might exist on
Windows hosts (bug #13478)
• Windows hosts: ﬁxed more startup problems on certain Windows hosts due to conﬂicts with anti-virus software; better error reporting (4.3.14 regression; bug #13187)

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15 Change log
• Windows hosts: propagate the process startup information to the child process (4.3.14 regression; bug #13243)
• Mac OS X hosts: don’t force using the discrete GPU (bug #11111)
• Windows Additions: some Windows 10 tweaks
• X11 guests: ﬁx a bug handling video driver display properties which prevented GNOME
Shell on Fedora 21 from starting
• Linux hosts / guests: ﬁxed a few remaining warnings in the kernel log if memory allocation fails (bug #11171)

15.8 Version 4.3.16 (2014-09-09)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: ﬁxed restoring 32-bit FPU state on 64-bit capable VMs and restoring guest FPU in raw-mode VMs (bug #12646; 4.3 regression)
• GUI: properly restore normal/scale mode guest-screen size after exiting full-screen/seamless mode • GUI: mini-toolbar should provoke less artifacts/conﬂicts with 3D guest rendering
• GUI: Mac OS X: Native full-screen multi-screen transition was able to blackout host-screens for nearly minute
• GUI: X11: Modern window managers should now use native full-screen multi-screen mapping API
• GUI: added extradata item for conﬁguring the mouse capture behavior, see chapter 9.20.11,
Conﬁguring automatic mouse capturing, page 203 (bug #3506)
• Storage: ﬁxed a VBoxSVC crash when querying an iSCSI target with authentication conﬁgured (4.3.14 regression)
• Storage: ﬁxed a rare data corruption during reads if another allocating write is running concurrently and accesses the same range
• Storage: ﬁxed a rare crash for certain VHD images from other products
• Storage: ﬁxed a rare release assertion when using the AHCI controller
• Floppy: ﬁxed read errors and guest memory corruption when running under control of
QEMM
• 3D: added experimental support for rendering on ofﬂine GPUs for Mac OS X host
• 3D: ﬁxed white window appearing on entering FullScreen mode on Mac OS X host
• 3D: ﬁxed video recording support for 3D data regression (bug #13073)
• 3D: ﬁxes for MS Ofﬁce 2013 support
• 3D: several ﬁxes
• Bridged Networking: improved IPv6 support when bridging to a wireless interface
• NAT: prevent internal DNS service from stuck in host-resolver mode when host was switched from one network to another one while host was sleeping (Mac OS X hosts)

260

15 Change log
• NAT: preserve DF (if possible) and TOS when proxying outbound UDP datagrams (bugs
#9440, #12309)
• NAT: don’t let multicast datagrams out (bug #7338)
• NAT: ﬁxed handling of large incoming UDP datagrams on Windows hosts (bug #12136)
• NAT: ﬁxed handling of the RFC 1533 DHCP PAD option
• NAT Network: ﬁxed inbound half-close on Windows hosts
• NAT Network: preserve IPv4 DF (if possible), TTL, TOS and IPv6 Hop Limit when proxying outbound UDP datagrams
• VRDP: ﬁxed a rare crash when using remote audio input
• USB: ﬁxed several regressions from 4.3.14 (bug #13320)
• Audio: made the HDA sound emulation work with certain Mac OS X guests (e.g. Mountain
Lion)
• Windows hosts: ﬁxed startup problems on certain Windows hosts due to conﬂicts with anti-virus software (4.3.14 regression; bug #13187)
• Windows hosts: ﬁxed 4.3.14 regression whereby AltGr stopped working for some people
(bug #13216)
• X11 hosts: made the extra key on Brazilian Thinkpads work (bug #8745)
• X11 hosts: ﬁxed a problem of input focus cycles and immediately released key presses in full screen mode (bug #13238)
• Linux hosts: ﬁxed ﬂooding the kernel log with USB related messages when passing through certain USB devices to a VM (bug #13085)
• Linux guests: stop applications crashing when drm_wait_vblank is called (bug #13265)
• Linux guests: ﬁx a crash in gnome-session (bug #13335)
• X11 guests: do not start VBoxClient over an SSH connection (bug #13107)
• X11 guests: added support for X.Org Server 1.16 (bug #13207)
• X11 guests: ﬁxed a wrong parameter in the video driver which caused problems with fullscreen X11 clients (bug #2748)
• VirtualKD: introduced stub/loader device for speeding up Windows kernel debugging, details see http://virtualkd.sysprogs.org/

15.9 Version 4.3.14 (2014-07-15)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: more ﬁxes for MSR emulation on certain hardware (bugs #12784, #12949,
#13034)
• VMM: improve MSI handling under rare circumstances (only relevant for the ICH9 chipset)
• VMM: ﬁxed #UD exception for 64-bit guests with the EFER.SCE bit and the SYSCALL instruction (VT-x only; 4.3 regression; bug #13008)

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• VMM: ﬁxed timekeeping after resuming SMP guests
• VMM: properly wake up a halted VCPU on NMI/SMI
• GUI: ﬁxed a potential crash
• GUI: ﬁxed stuck AltGr key on Windows hosts (bug #2537)
• GUI: ﬁxed a potential error during the version check
• GUI: shortcut change should not require Enter/Return (or other trigger) to conﬁrm (bugs
#12828, #12847, #12937, #13087)
• GUI: ﬁxed update check which was broken due to changing the location of the root certiﬁcates (bug #13096)
• VBoxManage: ﬁxed typo in showvminfo –machinereadable (bug #13176)
• NAT: ﬁxed inbound half-close (bug #13116)
• NAT: ﬁxed slow upload speed under certain conditions (bug #10034)
• NAT Network: ﬁxed potential loss of inbound TCP data
• NAT Network: ﬁxed potential inﬁnite stalls of TCP connections over IPv6
• NAT Network: ﬁxed resets of TCP connections on Windows hosts
• NAT Network: ﬁxed inbound half-close on Mac OS X hosts
• NAT Network: ﬁxed socket leak on Solaris hosts
• NAT Network: ﬁxed ping of mapped host loopback on Mac OS X and Solaris hosts, ﬁxed proxying of IMCP errors on Mac OS X
• Host-Only Network: ﬁxed SNMP ifConnectorPresent value on Windows (bug #13143)
• Storage: ﬁxed a possible crash with CD/DVD passthrough under certain circumstances
• Storage: ﬁxed a crash when trying to open an inaccessible QED or QCOW image (bug
#12613)
• Storage: ﬁxed data corruption or read errors under rare circumstances
• AHCI: ﬁxed a crash under rare circumstances
• USB: performance ﬁxes
• ICH9: properly reset MSI capability on reset
• Keyboard: active modiﬁer keys during suspend were stuck after resuming the host
• 3D: ﬁxed misbehavior with huge guests (i.e. guest more than 4GB guest memory
• 3D: several ﬁxes
• API: properly detect the Windows 8.1 guest OS type (bug #13090)
• ExtPack: cleanup of dangling uninstallation directories
• Linux hosts / guests: compile ﬁx for EL7 (bug #12638)
• Linux Additions: made 3D pass-through work with recent versions of Mesa in the guest
(bug #12941)

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15 Change log
• Linux Additions: Linux 3.16 ﬁxes (bug #13123)
• Mac OS X hosts: when scanning for host CD/DVD devices also consider BlueRay devices
• Mac OS X hosts: ﬁxed host shutdown and reboot delay caused by running VBoxSVC process in some cases
• OS/2 Additions: ﬁxed gengradd.dll library name (bug #12785)
• Solaris Additions: ﬁxed permissions of ﬁles and directories located on shared folders
• Windows host installer: ﬁxed the need for rebooting Windows after installation or upgrade, extended logging for NetFlt/NetAdp (un)installation

15.10 Version 4.3.12 (2014-05-16)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: ﬁxed an occasional Guru Meditation (Mac OS X hosts only; bugs #12727, #12954)
• VMM: ﬁxed a rare condition that would fail to invalidate guest TLB entries or would invalidate them when not required (Windows hosts only)
• VMM: ﬁxed a VERR_NOT_SUPPORTED Guru Meditation seen with certain guests, e.g.
OpenServer 5.0.7
• VMM: more ﬁxes for MSR emulation on certain hardware (bugs #12240, #12875)
• GUI: ﬁxed mouse positioning with mouse integration disabled and multiple guest screens
(Windows hosts only; bug #9059)
• GUI: ﬁxed crash in VM manager (bug #12878)
• GUI: ﬁxed crash under rare conditions on entering/exiting full-screen/seamless mode
• Shared Clipboard: don’t stop working after taking a snapshot (bug #12700)
• AHCI: ﬁxed a crash under rare circumstances
• API: ﬁxed a hang during VM shutdown under rare conditions
• NAT: ﬁxed generation of malformed ICMP error datagrams (4.3.10 regression)
• NAT: ﬁxed potential crash in DNS proxy
• NAT Network: don’t drop port forwarding rules after some time
• NAT: ﬁxed ARP cache corruption and network loss in Windows guest caused by iSCSI service activity
• USB: improved check if a storage device is currently mounted to the host when the device is about to be attached to the VM (Mac OS X hosts only; #11038)
• 3D support: several ﬁxes, including better support for Ubuntu 14.04
• VRDP: ﬁxed a potential crash on client disconnect (bug #12858)
• VBoxSVC: ﬁxed a race when a new client is started a few seconds after the last client terminated (Windows hosts only; bugs #11309, #12509)
• VBoxSVC: ﬁxed VirtualBox.xml registry corruption after VM renaming

263

15 Change log
• VBoxSVC: ﬁxed a potential crash caused by incorrect USB device ﬁlter (Mac OS X hosts only; #11038)
• Windows hosts: partly support 32-bit COM on 64-bit systems
• Windows host installer: implemented merge module (msm) support
• Linux hosts: ﬁxed dependency of boot script on older Debian systems (bug #12262)
• Linux guests: ﬁx symbolic link to shared folder helper (bug #12879)
• Linux Additions: don’t crash VBoxService during guest execute for users without a password (bug #12994)
• Linux Additions: ﬁxed a bug in guest execution where the guest process terminated with
VERR_INTERRUPTED to the host

15.11 Version 4.3.10 (2014-03-26)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: more work on improving the emulation of certain MSR registers on certain host
CPUs (e.g. bugs #12734, #12736, #12744, #12748, #12686, #12770)
• VMM: ﬁxed single-stepping for real-mode guests (VT-x without unrestricted guest execution) and some I/O instructions (bug #12636)
• VMM: ﬁxed a potential problem with COW pages if nested paging is not available
• GUI: Mac OS X: experimental native full screen support for Mountain Lion and Mavericks
(bug #12292)
• GUI: Mac OS X: removed the mini-toolbar minimize button which doesn’t work under Mac
OS X full screen mode anyway
• GUI: experimental HID LEDs synchronization for Windows and Mac OS X hosts: ﬁxed keyboard re-synchronization if the feature is disabled (as done by default; bug #12758)
• GUI: ﬁxed a potential crash when opening the preferences menu (bug #12862)
• OVF: ﬁxed a crash of the VirtualBox Manager when re-starting guest export (bug #12586)
• 3D support: several ﬁxes
• HGCM: ﬁxed a problem with saved states which could cause several guest misbehavior after a VM was started from a saved state
• Storage: ﬁxed a bug preventing to compact differential snapshots under certain conditions
• VBoxSVC: ﬁxed a segmentation fault on Linux hosts if a very long path exists under /dev
(bug #12760)
• API: ﬁxed guest misbehavior under certain conditions if a storage medium was attached or removed at VM runtime
• Windows installer: make the –silent parameter work again (bug #12764)
• Mac OS X Networking: prevent local trafﬁc (VM-to/from-host) from leaking to wire (bug
#12750)

264

15 Change log
• Windows Additions: ﬁxed the environment for guest processes (4.3.8 regression; bug
#12782)
• Windows Additions/WDDM: ﬁxed divide by zero exception with multiple guest screens under certain conditions
• Windows Additions/WDDM: ﬁxed crashes with 2D video acceleration enabled (4.3.8 regression; bug #12745)
• Linux Additions: install correctly on Ubuntu guest systems with a /usr/lib64 directory (bug
#12513)
• X11 Additions: ﬁx for the VBoxClient process not exiting correctly (bug #12348) and consuming too much processor time

15.12 Version 4.3.8 (2014-02-25)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: more work on improving the emulation of certain MSR registers (e.g. bugs #12224,
#12544)
• VMM: ﬁxed a VERR_INVALID_RPL Guru Meditation when booting certain guests (bug
#11350)
• VMM: experimental support for SSE 4.1 / SSE 4.2 passthrough, see the user manual how to enable it (bug #8651)
• VMM: ﬁx for recent Linux kernels with software virtualization
• GUI: experimental HID LEDs synchronization for Windows hosts, see chapter 9.28, Support for keyboard indicators synchronization, page 211
• GUI: warn the user if the Oracle Extension Pack is not installed and the user tries to activate the remote display feature (bug #9104)
• GUI: make sure that a minimized guest (using mini toolbar in full screen / seamless mode) keeps the minimized state (bug #12199)
• GUI: popup banner’s “do not show this message again” check-box replaced with corresponding button
• GUI: network adapter cables can now be connected/disconnected directly through the running virtual machine Devices / Network menu a Network status-bar indicator
• GUI: the new VM wizard now proposes 64-bit guests on 64-bit hosts by default; better distinction between 32-bit OS types 64-bit OS types (bug #12533)
• GUI: better error message if appliance import fails (bug #12657)
• GUI: allow to set host-combination to ’None’ using the Global settings / Input page (bug
#12730)
• GUI: don’t switch the guest to a black screen during online snapshot merge (4.3 regression)
• VBoxManage: when exporting an appliance, support the suppression of MAC addresses, which means they will be always recreated on import, avoiding duplicate MAC addresses for VMs which are imported several times

265

15 Change log
• AHCI: ﬁxed a VM hang during suspend under certain circumstances
• AHCI: ﬁxed a VM hang during online snapshot merge under certain circumstances
• AHCI: ﬁxed a bug which resulted in Windows XP guest hangs if a SATA CDROM is attached
(bug #12417)
• AHCI: ﬁxed a Guru Meditation under certain conditions
• AHCI: ejecting a CD/DVD medium failed under certain conditions
• AHCI: disk hotplugging ﬁxes
• NAT: transparent handling of host sleep/resume and network conﬁguration changes if the dnsproxy is enabled or if the hostresolver is used (bug #12441)
• NAT: ﬁxed crash and misbehaviour under some circumstances with ICMP packets having
TTL=1
• NAT Network: ﬁxed IPv6 reassembly
• NAT Network: ping proxy implemented
• OVF: ﬁxed reading of the OVF 0.9 section element (4.3 regression; bug #12345)
• OVF: several ﬁxes
• 3D support: several ﬁxes, multiscreen ﬁxes (e.g. bug #9124)
• 3D support: include 3D content in captured videos (bug #12666)
• 3D support: include 3D content in captured screenshot (bug #11758)
• VGA: proper handling of legacy graphics modes if the Guest Additions are active (bug
#6649)
• USB: ﬁxed crash during isochronous transfer under rare circumstances
• BIOS: better disk geometry handling of SCSI drives
• API: ﬁx crashes in Java API clients using the XPCOM binding, happened with output parameters only (bug #11232)
• VBoxSVC: documented the handling of host power management events (see chapter 9.26,
Handling of host power management events, page 211) and added an extradata item for conﬁguring the handling of the battery-low event (bug #9925)
• VBoxSVC: ﬁxed a bug which could trigger a crash if a VM snapshot was restored the second time and the VM has associated bandwidth groups (bug #12569)
• VBoxSVC: properly detect ifconﬁg if located in /bin (bug #12713)
• Shared Folders: ﬁxed a failure to restore transient shared folders when starting a VM from a saved state (bug #12578)
• Mac OS X hosts: ﬁxed issue when the application icon was frozen in the dock if the bridging interface was not connected to a network (bug #12241)
• Linux hosts: also consider the physical package ID when determining the number of physical CPU cores
• Linux hosts / guests: don’t warn in kernel log if memory allocation fails (bug #11171)

266

15 Change log
• Solaris hosts: ﬁxed the autostart SMF script (bug #11720)
• Windows hosts: ﬁxes for non-ANSI code page user names and similar environment contents
(bug #12596)
• Windows hosts / guests: ﬁxed setting and using a guest user’s process environment variables (relevant for Guest Control)
• Windows Additions: ﬁxed handle leaks in VBoxTray (bug #12563)
• Windows Additions: ﬁxed a crash while detecting active guest users
• Windows Additions: ﬁxed restoring backed up D3D ﬁles on XPDM -> WDDM upgrade
• Guest Control: ﬁxed setting and using a guest user’s process environment variables
• Linux Additions: support Enterprise Linux 6.5 kernels (bug #12505)
• Linux Additions: ﬁxed CPU hot-remove on newer Linux kernels
• Linux / Solaris Additions: don’t automount a shared folder which is already mounted
• X11 Additions: support X.Org Server 1.15 (bug #12623)

15.13 Version 4.3.6 (2013-12-18)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: ﬁxed a Guru Meditation VINF_EM_TRIPLE_FAULT caused by VMCB caching with nested paging on certain AMD CPUs (bug #12451)
• VMM: ﬁxed a Guru Meditation VERR_VMX_UNEXPECTED_INTERRUPTION_EXIT_TYPE while intercepting debug exceptions (VT-x only; bug #12410)
• VMM: ﬁxed a Guru Meditation VERR_SVM_UNEXPECTED_EXIT while intercepting debug register accesses (AMD-V only; bug #12481)
• VMM: ﬁxed a VERR_SSM_STRUCTURE_MAGIC error when trying to load a saved state made with VBox 4.3.4 when VT-x/AMD-V is disabled. Unfortunately, VBox 4.3.4 produced broken saved states for this conﬁguration so you have to discard these states (bug #12414)
• VMM: added a few more MSRs to the whitelist required by certain guests (bug #12245)
• GUI: ﬁxed deleting of inaccessible VMs (4.3 regression; bug #12205)
• GUI: ﬁxed warnings in VM settings / number of guest processors (bug #12480)
• Main: don’t automatically enable 64-bit guests on 64-bit hosts if VT-x/AMD-V is not available (bug #12424)
• Main: always expose the DMI memory information to Windows 2012 guests (bug #12017)
• Main: ﬁxed occasional crashes on guest display resolution change (bug #7063)
• Main: ﬁxed reporting back temporary name when calling IGuestSession::DirectoryCreateTemp()
(bug #12498)
• API: ﬁx for a hang when launching a GUI VM through the API, which crashes due to GUI unavailability • Storage: ﬁx for BLKCACHE_IOERR runtime errors under rare circumstances (bug #11030)

267

15 Change log
• Network: allow to start more than 5 PCNet instances (bug #12426)
• E1000: if the cable was disconnected before the guest initialized the device, the link status was not properly set to ’down’ after the initialization completed despite the fact that there was no connection
• 3D support: ﬁxed offset of guest 3D image elements (Mac OS X Retina hosts only; bug
#11021)
• Solaris hosts: ﬁxed accessing the host driver from non-global zones (4.3 regression; bug
#12271)

15.14 Version 4.3.4 (2013-11-29)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: ﬁx for a bug in the Local APIC emulation causing a BSOD when booting certain guests (4.3.0 regression; bug #12240)
• VMM: ﬁxed loading of saved states if VT-x/AMD-V was disabled (4.3.2 regression; bug
#12291)
• VMM: ﬁxed single-stepping inside the guest for certain instructions (VT-x only; bug
#10947)
• VMM: ﬁxed a performance issue involving APIC accesses after rebooting a VM (4.3.0 regression; VT-x only; bug #12296)
• VMM: ﬁxed TPR patching to be enabled for 32-bit guests even when the chosen guest type is 64-bit (4.3.0 regression; AMD-V only)
• VMM: ﬁxed occasional VINF_EM_TRIPLE_FAULT errors on hosts without the unrestricted guest execution feature (bug #12198)
• GUI: don’t bother the user with the BPP warning if no Guest Additions are installed
• GUI: ﬁxed machine-window paint artifacts on VM reboot / guest-screen resize
• GUI: make sure the assigned license and description are attached to the exported appliance
• GUI: ﬁxed bugs in close VM action restrictions handling (bug #12333)
• GUI: ﬁxed incorrect wizards text colors for some unusual look and feel styles (bug #11743)
• GUI: should restore seamless mode as soon as possible after VM reboot or shutdown
• GUI: ﬁxes for medium enumeration
• GUI: the OS X hot corners were not accessible while a VirtualBox VM is running (Mac OS
X hosts only; bug #4139)
• GUI: ﬁxed an old bug which bared the host from cleanly shutdown / reboot if the VM selector window is open (Mac OS X hosts only; bug #8254)
• Host-only Networking: ﬁxed creating of host-only network interfaces (4.3.0 regression; bug #12182)
• NAT: don’t run into an inﬁnite loop in case the host cannot access any DNS server (4.3.0 regression; bug #12300)

268

15 Change log
• NAT: don’t re-connect the cable if the DNS information changes and the cable was disconnected before (4.3.0 regression; bug #12225)
• NAT: ﬁxed several issues with automatically starting / terminating of NAT networks on VM start / stop and conﬁguration changes
• VBoxNetDHCP: don’t block prevent VBoxSVC from terminating (bug #12264)
• 2D Video acceleration: ﬁx crashes on presentation mode switches (bug #9194)
• BusLogic: allow to run VMs with more than one BusLogic SCSI controller enabled
• Keyboard: ﬁxed a VM crash if a VM was resumed from a saved state where at least one key was pressed (bug #11289)
• VBoxSVC: ﬁxed a heap corruption under certain conditions (4.3.0 regression)
• VBoxSVC: ﬁxed a race leading to a hang during initialization (bug #12349)
• OVF: ﬁxed import logic for OVF appliances containing multiple VMs
• OVF: improved logic for ﬁnding an appropriate image format during OVF import
• API: block the removal of the current snapshot if it has child snapshots (only relevant for
VMs without snapshottable hard disks, their presence always prevented removal), which resulted in VM conﬁg corruption
• API: mark VM conﬁgs with snapshots but without current snapshot as inaccessible, as this combination is nonsense
• API: ﬁxed information for some automatically generated events (only with XPCOM, Windows host was not affected), which caused errors when getting some of the attributes over the webservice (bug #12379)
• SDK: extended the functionality coverage for the C bindings
• Guest Control: various bugﬁxes and improved VBoxManage help (bugs #8072, #11044,
#12336, #12338, #12346, #12371)
• Windows hosts: another attempt to ﬁx the massive DPC latency (bug #6242)
• Windows host installer: make registering ﬁle extensions optional, contributed by Tal Aloni
(bug #8009)
• Mac OS X hosts: properly sign the kernel extensions for Mavericks hosts (bug #12256)
• Mac OS X hosts: ﬁxed a bug where the VirtualBox dock icon was not properly removed from the dock after a VM terminated preventing Mavericks hosts from shutting down (bug
#12241)
• Mac OS X hosts: ﬁxed minor installer issue (bug #12275)
• Linux hosts / guests: Linux 3.13 compile ﬁxes (bug #12358)
• Linux guests: build the vboxvideo kernel module correctly on OL/RHEL 6.1 guests (bug
#11996)
• Linux guests: make 3D work on Slackware 14.1 (bug #12320 comments 3 and 4)
• Guest Additions/3D: ﬁxed an occasional dead-lock (bug #12319)
• Windows Additions/3D: ﬁxed possible memory leaking (bug #12228)

269

15 Change log
• Windows Additions/XPDM: use separate tables containing valid video modes for each virtual monitor
• Windows Additions: ﬁxed automatic logins for Vista and newer Windows guests (bug
#12332)

15.15 Version 4.3.2 (2013-11-01)
This is a maintenance release. The following items were ﬁxed and/or added:
• VMM: ﬁxed restoring of the auxiliary TSC MSR in VT-x that caused host BSODs on Windows
8.1 hosts and unpredictable behavior on other hosts (bug #12237)
• VMM: provide fake values for a couple of MSRs to make more guests happy on certain hosts • VMM: ﬁxed detection of VT-x on certain machines where the BIOS would not set the VMX
LOCK feature bit, which affected the VM settings in the GUI
• VMM: ﬁxed TPR threshold which caused BSODs on Windows XP guests that use the I/O
APIC (VT-x only; bug #12227)
• VMM: ﬁxed PATM saved state incompatibility for software virtualized VMs (bug #12222)
• VMM: don’t fail if AMD-V isn’t available if the VM is conﬁgured to use software virtualization
• GUI: ﬁxed guest resize breakage on visual representation mode change (when switching from normal to full screen etc)
• GUI: make sure the guest screen is resized after restoring a VM from a saved state if the host screen size changed
• GUI: disabled SCROLL LED sync from HID LEDs synchronization (Mac OS X hosts only)
• Webcam passthrough improvements including GUI support (see chapter 9.7.1, Using a host webcam in the guest, page 181)
• Guest Control: implemented more IGuestSession methods
• Guest Control: added support for deleting and renaming guest ﬁles + directories in VBoxManage
• Guest Control: various bugﬁxes
• API: incorrect handling of hardware UUID default value, resulting in an all zero
DMI/SMBIOS UUID, which leads to Windows requesting re-activation (4.3 regression; bug #12244)
• 3D support: ﬁxed crash on shutdown if 2D video acceleration is enabled (Mac OS X hosts only) • 3D support: miscellaneous ﬁxes
• Storage: ﬁxed detection of CD/DVD media when switching from an empty to a host drive with passthrough enabled
• Storage: ﬁxed hang of the VM process when the disk is full under certain circumstances
• NAT: listen for changes of NAT Network setting at runtime

270

15 Change log
• NAT: NAT Network DHCP server now saves leases to a persistent storage
• Main: monitor changes in host DNS conﬁguration
• Mac OS X host: reworked a mechanism of adding a VM desktop alias from the VM selector
• Mac OS X installer: remove old kernel extensions during upgrade (bug #12258)
• Linux Additions: correctly set umask before installing (bug #12166)
• X11 Additions/3D: ﬁx freezes starting 3D desktop (bug #11503, thank you Sam Spilsbury)
• X11 Additions/3D: ﬁx depth buffer support (bug #11905)
• X11 Additions/3D: ﬁx Age Of Empires 3 rendering (bug #11331)
• Windows Additions/3D: ﬁx Google Earth plugin rendering
• Windows Additions/WDDM: autoresize ﬁxes

15.16 Version 4.3.0 (2013-10-15)
This is a major update. The following major new features were added:
• VMM: major rewrite of the VT-x code and the AMD-V code including many bug ﬁxes and performance improvements (for example bug #9659)
• VMM: introduced a lightweight instruction interpreter for situations not handled by hardware virtualization
• GUI: extended messaging mechanism (new non-modal popup overlays used to show noncritical warnings and provide user with additional information)
• GUI: keyboard shortcuts management (input page of global preferences extended with possibility to edit general keyboard shortcuts for VirtualBox Manager and Virtual Machine)
• GUI: video capturing support (bug #4766)
• Added USB touch device emulation
• Added experimental support for webcam passthrough complementing USB passthrough
(see chapter 9.7.1, Using a host webcam in the guest, page 181)
• Added SCSI CD-ROM emulation, including boot support
• VRDP: support for IPv6
• Guest Control: guest sessions now are running in dedicated, impersonated session processes (needs at least Guest Additions 4.3 installed)
• Guest Control: implemented IGuestFile support
• NAT: experimental virtual router mode: several VMs are attached to the same internal network and share one NAT service (see chapter 6.4, Network Address Translation Service
(experimental), page 98)
In addition, the following items were ﬁxed and/or added:
• VMM: signiﬁcantly improved performance of NetWare 5.x/6.x guests on host systems without nested paging support

271

15 Change log
• VMM: ﬁxed losing host NMIs while in VT-x guest-context
• VMM: changed order of actions in emulated task switch (bug #10532)
• VMM: allow to activate VT-x while in SMX mode and provide more information if that is not possible
• GUI: update check uses https
• GUI: numerous minor internal cleanups and bug ﬁxes
• GUI: HID LEDs synchronization when switching between guest window(s) and host (Mac
OS X hosts only)
• GUI, VBoxManage: when unregistering a VM, also unregister the hard disk images which are used exclusively (bug #10311)
• GUI: use the number of physical presented processor cores instead of the number of logical processor cores to check if the users assigned too many virtual CPUs to the guest
• Snapshots: made live snapshots work again (bug #9255)
• Teleportation: made it work again (bug #9455)
• Storage: implemented AHA-154x compatibility mode in the emulated BusLogic SCSI HBA
• Storage: signiﬁcantly improved performance of large ATAPI PIO transfers (BeOS, Minix 3 guests affected)
• Storage: added ﬂoppy formatting emulation (NB: cannot be used to change existing media geometry) • Settings: global and per-VM default frontend conﬁguration, useful to select the use of alternative VM frontends
• Settings: limit depth of snapshot tree to 250 levels, as more will lead to decreased performance and may trigger crashes
• Settings: the per-VM hwvirtextexcl setting has been replaced by a global hwvirtexclusive property • Main: new event queue implementation which does not use the host’s native event queue for processing VirtualBox events anymore
• Main: eliminate the use of SysV semaphores on all host OSes other than Windows, namely
Linux, Solaris and Mac OS X, with the consequence that no system reconﬁguration is needed to run more than approximately 100 VMs
• Main: use the XDG standard conﬁguration folder instead of .VirtualBox on systems where it is appropriate (bug #5099)
• Main: extension pack framework can now support loading HGCM modules, contributed by
Jeff Westphal
• VBoxManage: list more information about hard disk/DVD/ﬂoppy media, and support the
--long option to show really all available details
• VBoxManage: added support for optional command line parameters for the automatic
Guest Additions update
• VBoxManage: added support for listing active guest sessions, guest processes and/or guest ﬁles via guestcontrol list <all|sessions|processes|files>

272

15 Change log
• VBoxManage: added support for closing active guest sessions via guestcontrol session close --session-id <ID>| --session-name <name or pattern>|--all

• VBoxManage: added support for terminating active guest processes via guestcontrol process kill|close|terminate --session-id <ID>| --session-name <name or pattern> <PID> ... <PID n> or guestcontrol [p[s]]kill --session-id <ID>|
--session-name <name or pattern> <PID> ... <PID n>

• VBoxManage: added support for watching guest sessions via guestcontrol watch
• VBoxManage: added modifyvm --triplefaultreset to make the VM reset on triple fault instead of triggering a Guru Meditation (see chapter 8.8, VBoxManage modifyvm, page 129)
• 3D support: several ﬁxes
• 3D support: several ﬁxes for Mac OS X hosts
• OVF: several ﬁxes
• Extpack Installer: make it work if the ﬁle is located in a folder with special characters
• Keyboard: ﬁx for reporting key sequences like Ctrl+Alt+Del for the USB keyboard emulation
• Shared Clipboard/X11: support for BMP-format images, contributed by François Revol
• Mac OS X hosts: limited support for Mac OS X 10.9 (Mavericks)
• Mac OS X hosts: use a launchd script instead of the deprecated StartupItem mechanism
(bug #8940)
• Windows hosts: don’t cause massive DPC latency (only on certain hosts; still needs improving; bug #6242)
• Windows hosts: consider symlinks when retrieving volume information (bug #11962)
• Windows hosts: ﬁxed an issue with USB2 devices being inaccessible when plugged into
USB 3.0 ports
• Windows Additions: ﬁxed misbehavior with guest display power management (WDDM driver only; bug #11170)
• Windows Additions: ﬁxed memory leak caused by WTSQuerySessionInformation() on Windows 2000 guests (bug #12072)
• Windows Additions: ability to track guest user idle times through the newly introduced event IGuestUserStateChangedEvent
• Linux Additions: ﬁxed udev detection in the init script with Linux 3.x kernels

15.17 Older Change log details
With VirtualBox 5.0, changelog information for versions before 4.3 was removed in order to save space. To access this information, please consult the User Manual of VirtualBox version 4.3 or earlier. 273

16 Third-party materials and licenses
VirtualBox incorporates materials from several Open Source software projects. Therefore the use of these materials by VirtualBox is governed by different Open Source licenses. This document reproduces these licenses and provides a list of the materials used and their respective licensing conditions. Section 1 contains a list of the materials used. Section 2 reproduces the applicable
Open Source licenses. For each material, a reference to its license is provided.
The source code for the materials listed below as well as the rest of the VirtualBox code which is released as open source are available at http://www.virtualbox.org, both as tarballs for particular releases and as a live SVN repository.

16.1 Materials
• VirtualBox contains portions of QEMU which is governed by the licenses in chapter 16.2.5,
X Consortium License (X11), page 292 and chapter 16.2.2, GNU Lesser General Public License
(LGPL), page 281 and
(C) 2003-2005 Fabrice Bellard; Copyright (C) 2004-2005 Vassili Karpov (malc); Copyright
(c) 2004 Antony T Curtis; Copyright (C) 2003 Jocelyn Mayer
• VirtualBox contains code which is governed by the license in chapter 16.2.5, X Consortium
License (X11), page 292 and
Copyright 2004 by the Massachusetts Institute of Technology.
• VirtualBox contains code of the BOCHS VGA BIOS which is governed by the license in chapter 16.2.2, GNU Lesser General Public License (LGPL), page 281 and
Copyright (C) 2001, 2002 the LGPL VGABios developers Team.
• VirtualBox contains code of the BOCHS ROM BIOS which is governed by the license in chapter 16.2.2, GNU Lesser General Public License (LGPL), page 281 and
Copyright (C) 2002 MandrakeSoft S.A.; Copyright (C) 2004 Fabrice Bellard; Copyright (C)
2005 Struan Bartlett.
• VirtualBox contains the zlib library which is governed by the license in chapter 16.2.6, zlib license, page 292 and
Copyright (C) 1995-2003 Jean-loup Gailly and Mark Adler.
• VirtualBox may contain OpenSSL which is governed by the license in chapter 16.2.7,
OpenSSL license, page 292 and
Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com). This product includes software written by Tim Hudson (tjh@cryptsoft.com).
• VirtualBox may contain NSPR and XPCOM which is governed by the license in chapter
16.2.3, Mozilla Public License (MPL), page 286 and
Copyright (C) The Authors.
• VirtualBox contains Slirp which is governed by the license in chapter 16.2.8, Slirp license, page 293 and was written by Danny Gasparovski.
Copyright (C) 1995, 1996 All Rights Reserved.

274

16 Third-party materials and licenses
• VirtualBox contains liblzf which is governed by the license in chapter 16.2.9, liblzf license, page 294 and
Copyright (C) 2000-2005 Marc Alexander Lehmann <schmorp@schmorp.de>
• VirtualBox may ship with a modiﬁed copy of rdesktop which is governed by the license in chapter 16.2.1, GNU General Public License (GPL), page 277 and
Copyright (C) Matthew Chapman and others.
• VirtualBox may ship with a copy of kchmviewer which is governed by the license in chapter
16.2.1, GNU General Public License (GPL), page 277 and
Copyright (C) George Yunaev and others.
• VirtualBox may contain Etherboot which is governed by the license in chapter 16.2.1, GNU
General Public License (GPL), page 277 with the exception that aggregating Etherboot with another work does not require the other work to be released under the same license (see http://etherboot.sourceforge.net/clinks.html). Etherboot is
Copyright (C) Etherboot team.
• VirtualBox may contain iPXE which is governed by the license in chapter 16.2.1, GNU
General Public License (GPL), page 277 and
Copyright (C) Michael Brown <mbrown@fensystems.co.uk> and others.
• VirtualBox contains code from Wine which is governed by the license in chapter 16.2.2,
GNU Lesser General Public License (LGPL), page 281 and
Copyright 1993 Bob Amstadt, Copyright 1996 Albrecht Kleine, Copyright 1997 David
Faure, Copyright 1998 Morten Welinder, Copyright 1998 Ulrich Weigand, Copyright 1999
Ove Koven
• VirtualBox contains code from lwIP which is governed by the license in chapter 16.2.11, lwIP license, page 294 and
Copyright (C) 2001, 2002 Swedish Institute of Computer Science.
• VirtualBox contains libxml which is governed by the license in chapter 16.2.12, libxml license, page 295 and
Copyright (C) 1998-2003 Daniel Veillard.
• VirtualBox contains libxslt which is governed by the license in chapter 16.2.13, libxslt licenses, page 295 and
Copyright (C) 2001-2002 Daniel Veillard and Copyright (C) 2001-2002 Thomas Broyer,
Charlie Bozeman and Daniel Veillard.
• VirtualBox contains code from the gSOAP XML web services tools, which are licensed under the license in chapter 16.2.14, gSOAP Public License Version 1.3a, page 296 and
Copyright (C) 2000-2007, Robert van Engelen, Genivia Inc., and others.
• VirtualBox ships with the application tunctl (shipped as VBoxTunctl) from the User-mode
Linux suite which is governed by the license in chapter 16.2.1, GNU General Public License
(GPL), page 277 and
Copyright (C) 2002 Jeff Dike.
• VirtualBox contains code from Chromium, an OpenGL implementation, which is goverened by the licenses in chapter 16.2.15, Chromium licenses, page 301 and
Copyright (C) Stanford University, The Regents of the University of California, Red Hat, and others.

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16 Third-party materials and licenses
• VirtualBox contains libcurl which is governed by the license in chapter 16.2.16, curl license, page 303 and
Copyright (C) 1996-2009, Daniel Stenberg.
• VirtualBox contains dnsproxy which is governed by the license in chapter 16.2.4, MIT License, page 292 and
Copyright (c) 2003, 2004, 2005 Armin Wolfermann.
• VirtualBox may contain iniparser which is governed by the license in chapter 16.2.4, MIT
License, page 292 and
Copyright (c) 2000-2008 by Nicolas Devillard.
• VirtualBox contains some code from libgd which is governed by the license in chapter
16.2.17, libgd license, page 303 and
Copyright 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Pierre-Alain Joye
(pierre@libgd.org).
• VirtualBox contains code from the EFI Development Kit II which is governed by the license in chapter 16.2.18, BSD license from Intel, page 304 and
Copyright (c) 2004-2008, Intel Corporation.
• VirtualBox contains libjpeg which is governed by the license in chapter 16.2.19, libjpeg
License, page 304 and
Copyright (C) 1991-2010, Thomas G. Lane, Guido Vollbeding.
• VirtualBox may contain x86 SIMD extension for IJG JPEG library which is governed by the license in chapter 16.2.20, x86 SIMD extension for IJG JPEG library license, page 305 and
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB; Copyright 2010 D.
R. Commander; Copyright (C) 1999-2006, MIYASAKA Masaru.
• VirtualBox may ship a copy of Qt which is governed by the license in chapter 16.2.2, GNU
Lesser General Public License (LGPL), page 281 and
Copyright (C) 2010, 2011 Nokia Corporation and/or its subsidiary(-ies).
• VirtualBox contains parts of the FreeBSD kernel which is governed by the license in chapter
16.2.21, FreeBSD license, page 305.
• VirtualBox contains parts of the NetBSD kernel which is governed by the license in chapter
16.2.22, NetBSD license, page 306.
• VirtualBox contains portions of liblightdm-gobject which is governed by the license in chapter 16.2.2, GNU Lesser General Public License (LGPL), page 281 and
Copyright (C) 2010-2013 Canonical Ltd.; Copyright (C) 2010-2011 Robert Ancell.
• VirtualBox contains portions of glib which is governed by the license in chapter 16.2.2,
GNU Lesser General Public License (LGPL), page 281 and
Copyright (C) 1995-2011 The Glib team
• VirtualBox contains portions of PCRE which is governed by the license in chapter 16.2.23,
PCRE license, page 306 and
Copyright (c) 1997-2012 University of Cambridge; Copyright(c) 2009-2012 Zoltan Herczeg; Copyright (c) 2007-2012, Google Inc.

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16 Third-party materials and licenses
• VirtualBox contains portions of libfﬁ which is governed by the license in chapter 16.2.24, libfﬁ license, page 307 and
Copyright (c) 1996-2012 Anthony Green, Red Hat, Inc and others. See source ﬁles for details. • VirtualBox contains portions of FLTK which is governed by the licenses in chapter 16.2.25,
FLTK license, page 308 and chapter 16.2.2, GNU Lesser General Public License (LGPL), page
281 and
Copyright (C) 1991-2012 The FLTK team
• VirtualBox contains portions of Expat which is governed by the license in chapter 16.2.26,
Expat license, page 308 and
Copyright (c) 1998, 1999, 2000 Thai Open Source Software Center Ltd and Clark Cooper;
Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006 Expat maintainers.
• VirtualBox contains portions of Fontconﬁg which is governed by the license in chapter
16.2.27, Fontconﬁg license, page 308 and
Copyright (C) 2001, 2003 Keith Packard
• VirtualBox contains portions of Freetype which is governed by the license in chapter
16.2.28, Freetype license, page 309 and
Copyright 2012 The FreeType Project (www.freetype.org). All rights reserved.
• VirtualBox may contain code from the WebM VP8 Codec SDK which is governed by the license in chapter 16.2.29, VPX License, page 311 and
Copyright (c) 2010, The WebM Project authors. All rights reserved.

16.2 Licenses
16.2.1 GNU General Public License (GPL)
GNU GENERAL PUBLIC LICENSE Version 2, June 1991
Copyright (C) 1989, 1991 Free Software Foundation, Inc.
51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
Preamble
The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software–to make sure the software is free for all its users. This General Public
License applies to most of the Free Software Foundation’s software and to any other program whose authors commit to using it. (Some other Free Software Foundation software is covered by the GNU Library General Public License instead.) You can apply it to your programs, too.
When we speak of free software, we are referring to freedom, not price. Our General Public
Licenses are designed to make sure that you have the freedom to distribute copies of free software
(and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things.
To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These restrictions translate to certain responsibilities for you if you distribute copies of the software, or if you modify it.

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16 Third-party materials and licenses
For example, if you distribute copies of such a program, whether gratis or for a fee, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.
We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the software.
Also, for each author’s protection and ours, we want to make certain that everyone understands that there is no warranty for this free software. If the software is modiﬁed by someone else and passed on, we want its recipients to know that what they have is not the original, so that any problems introduced by others will not reﬂect on the original authors’ reputations.
Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone’s free use or not licensed at all.
The precise terms and conditions for copying, distribution and modiﬁcation follow.
GNU GENERAL PUBLIC LICENSE TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION
AND MODIFICATION
0. This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License.
The “Program”, below, refers to any such program or work, and a “work based on the Program” means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modiﬁcations and/or translated into another language. (Hereinafter, translation is included without limitation in the term
“modiﬁcation”.) Each licensee is addressed as “you”.
Activities other than copying, distribution and modiﬁcation are not covered by this License; they are outside its scope. The act of running the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on the Program (independent of having been made by running the Program). Whether that is true depends on what the
Program does.
1. You may copy and distribute verbatim copies of the Program’s source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients of the Program a copy of this License along with the Program.
You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.
2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modiﬁcations or work under the terms of Section 1 above, provided that you also meet all of these conditions:
a) You must cause the modiﬁed ﬁles to carry prominent notices stating that you changed the ﬁles and the date of any change.
b) You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.
c) If the modiﬁed program normally reads commands interactively when run, you must cause it, when started running for such interactive use in the most ordinary way, to print or display an announcement including an appropriate copyright notice and a notice that there is no warranty
(or else, saying that you provide a warranty) and that users may redistribute the program under these conditions, and telling the user how to view a copy of this License. (Exception: if the
Program itself is interactive but does not normally print such an announcement, your work based on the Program is not required to print an announcement.)
These requirements apply to the modiﬁed work as a whole. If identiﬁable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you

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16 Third-party materials and licenses distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this
License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.
Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.
In addition, mere aggregation of another work not based on the Program with the Program
(or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.
3. You may copy and distribute the Program (or a work based on it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you also do one of the following:
a) Accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or,
b) Accompany it with a written offer, valid for at least three years, to give any third party, for a charge no more than your cost of physically performing source distribution, a complete machine-readable copy of the corresponding source code, to be distributed under the terms of
Sections 1 and 2 above on a medium customarily used for software interchange; or,
c) Accompany it with the information you received as to the offer to distribute corresponding source code. (This alternative is allowed only for noncommercial distribution and only if you received the program in object code or executable form with such an offer, in accord with
Subsection b above.)
The source code for a work means the preferred form of the work for making modiﬁcations to it. For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface deﬁnition ﬁles, plus the scripts used to control compilation and installation of the executable. However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable.
If distribution of executable or object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place counts as distribution of the source code, even though third parties are not compelled to copy the source along with the object code.
4. You may not copy, modify, sublicense, or distribute the Program except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense or distribute the Program is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.
5. You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Program (or any work based on the Program), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the
Program or works based on it.
6. Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients’ exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties to this License.
7. If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court

279

16 Third-party materials and licenses order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Program at all. For example, if a patent license would not permit royalty-free redistribution of the Program by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Program.
If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply and the section as a whole is intended to apply in other circumstances.
It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system, which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice.
This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.
8. If the distribution and/or use of the Program is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Program under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this
License incorporates the limitation as if written in the body of this License.
9. The Free Software Foundation may publish revised and/or new versions of the General
Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.
Each version is given a distinguishing version number. If the Program speciﬁes a version number of this License which applies to it and “any later version”, you have the option of following the terms and conditions either of that version or of any later version published by the Free
Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation.
10. If you wish to incorporate parts of the Program into other free programs whose distribution conditions are different, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally. NO WARRANTY
11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE
THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND
PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO
LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU

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16 Third-party materials and licenses
OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY
OF SUCH DAMAGES.
END OF TERMS AND CONDITIONS

16.2.2 GNU Lesser General Public License (LGPL)
GNU LESSER GENERAL PUBLIC LICENSE Version 2.1, February 1999
Copyright (C) 1991, 1999 Free Software Foundation, Inc. 59 Temple Place, Suite 330, Boston,
MA 02111-1307 USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
[This is the ﬁrst released version of the Lesser GPL. It also counts as the successor of the GNU
Library Public License, version 2, hence the version number 2.1.]
Preamble
The licenses for most software are designed to take away your freedom to share and change it.
By contrast, the GNU General Public Licenses are intended to guarantee your freedom to share and change free software–to make sure the software is free for all its users.
This license, the Lesser General Public License, applies to some specially designated software packages–typically libraries–of the Free Software Foundation and other authors who decide to use it. You can use it too, but we suggest you ﬁrst think carefully about whether this license or the ordinary General Public License is the better strategy to use in any particular case, based on the explanations below.
When we speak of free software, we are referring to freedom of use, not price. Our General
Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish); that you receive source code or can get it if you want it; that you can change the software and use pieces of it in new free programs; and that you are informed that you can do these things.
To protect your rights, we need to make restrictions that forbid distributors to deny you these rights or to ask you to surrender these rights. These restrictions translate to certain responsibilities for you if you distribute copies of the library or if you modify it.
For example, if you distribute copies of the library, whether gratis or for a fee, you must give the recipients all the rights that we gave you. You must make sure that they, too, receive or can get the source code. If you link other code with the library, you must provide complete object ﬁles to the recipients, so that they can relink them with the library after making changes to the library and recompiling it. And you must show them these terms so they know their rights.
We protect your rights with a two-step method: (1) we copyright the library, and (2) we offer you this license, which gives you legal permission to copy, distribute and/or modify the library.
To protect each distributor, we want to make it very clear that there is no warranty for the free library. Also, if the library is modiﬁed by someone else and passed on, the recipients should know that what they have is not the original version, so that the original author’s reputation will not be affected by problems that might be introduced by others.
Finally, software patents pose a constant threat to the existence of any free program. We wish to make sure that a company cannot effectively restrict the users of a free program by obtaining a restrictive license from a patent holder. Therefore, we insist that any patent license obtained for a version of the library must be consistent with the full freedom of use speciﬁed in this license.
Most GNU software, including some libraries, is covered by the ordinary GNU General Public
License. This license, the GNU Lesser General Public License, applies to certain designated libraries, and is quite different from the ordinary General Public License. We use this license for certain libraries in order to permit linking those libraries into non-free programs.
When a program is linked with a library, whether statically or using a shared library, the combination of the two is legally speaking a combined work, a derivative of the original library.
The ordinary General Public License therefore permits such linking only if the entire combination

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16 Third-party materials and licenses ﬁts its criteria of freedom. The Lesser General Public License permits more lax criteria for linking other code with the library.
We call this license the “Lesser” General Public License because it does Less to protect the user’s freedom than the ordinary General Public License. It also provides other free software developers Less of an advantage over competing non-free programs. These disadvantages are the reason we use the ordinary General Public License for many libraries. However, the Lesser license provides advantages in certain special circumstances.
For example, on rare occasions, there may be a special need to encourage the widest possible use of a certain library, so that it becomes a de-facto standard. To achieve this, non-free programs must be allowed to use the library. A more frequent case is that a free library does the same job as widely used non-free libraries. In this case, there is little to gain by limiting the free library to free software only, so we use the Lesser General Public License.
In other cases, permission to use a particular library in non-free programs enables a greater number of people to use a large body of free software. For example, permission to use the GNU C
Library in non-free programs enables many more people to use the whole GNU operating system, as well as its variant, the GNU/Linux operating system.
Although the Lesser General Public License is Less protective of the users’ freedom, it does ensure that the user of a program that is linked with the Library has the freedom and the wherewithal to run that program using a modiﬁed version of the Library.
The precise terms and conditions for copying, distribution and modiﬁcation follow. Pay close attention to the difference between a “work based on the library” and a “work that uses the library”. The former contains code derived from the library, whereas the latter must be combined with the library in order to run.
GNU LESSER GENERAL PUBLIC LICENSE TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. This License Agreement applies to any software library or other program which contains a notice placed by the copyright holder or other authorized party saying it may be distributed under the terms of this Lesser General Public License (also called “this License”). Each licensee is addressed as “you”.
A “library” means a collection of software functions and/or data prepared so as to be conveniently linked with application programs (which use some of those functions and data) to form executables. The “Library”, below, refers to any such software library or work which has been distributed under these terms. A “work based on the Library” means either the Library or any derivative work under copyright law: that is to say, a work containing the Library or a portion of it, either verbatim or with modiﬁcations and/or translated straightforwardly into another language.
(Hereinafter, translation is included without limitation in the term “modiﬁcation”.)
“Source code” for a work means the preferred form of the work for making modiﬁcations to it.
For a library, complete source code means all the source code for all modules it contains, plus any associated interface deﬁnition ﬁles, plus the scripts used to control compilation and installation of the library.
Activities other than copying, distribution and modiﬁcation are not covered by this License; they are outside its scope. The act of running a program using the Library is not restricted, and output from such a program is covered only if its contents constitute a work based on the Library
(independent of the use of the Library in a tool for writing it). Whether that is true depends on what the Library does and what the program that uses the Library does.
1. You may copy and distribute verbatim copies of the Library’s complete source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and distribute a copy of this License along with the Library.
You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.

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2. You may modify your copy or copies of the Library or any portion of it, thus forming a work based on the Library, and copy and distribute such modiﬁcations or work under the terms of Section 1 above, provided that you also meet all of these conditions:
a) The modiﬁed work must itself be a software library.
b) You must cause the ﬁles modiﬁed to carry prominent notices stating that you changed the ﬁles and the date of any change.
c) You must cause the whole of the work to be licensed at no charge to all third parties under the terms of this License.
d) If a facility in the modiﬁed Library refers to a function or a table of data to be supplied by an application program that uses the facility, other than as an argument passed when the facility is invoked, then you must make a good faith effort to ensure that, in the event an application does not supply such function or table, the facility still operates, and performs whatever part of its purpose remains meaningful.
(For example, a function in a library to compute square roots has a purpose that is entirely welldeﬁned independent of the application. Therefore, Subsection 2d requires that any applicationsupplied function or table used by this function must be optional: if the application does not supply it, the square root function must still compute square roots.)
These requirements apply to the modiﬁed work as a whole. If identiﬁable sections of that work are not derived from the Library, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Library, the distribution of the whole must be on the terms of this
License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.
Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Library.
In addition, mere aggregation of another work not based on the Library with the Library (or with a work based on the Library) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.
3. You may opt to apply the terms of the ordinary GNU General Public License instead of this
License to a given copy of the Library. To do this, you must alter all the notices that refer to this
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Once this change is made in a given copy, it is irreversible for that copy, so the ordinary GNU
General Public License applies to all subsequent copies and derivative works made from that copy. This option is useful when you wish to copy part of the code of the Library into a program that is not a library.
4. You may copy and distribute the Library (or a portion or derivative of it, under Section
2) in object code or executable form under the terms of Sections 1 and 2 above provided that you accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange.
If distribution of object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place satisﬁes the requirement to distribute the source code, even though third parties are not compelled to copy the source along with the object code.
5. A program that contains no derivative of any portion of the Library, but is designed to work with the Library by being compiled or linked with it, is called a “work that uses the Library”.

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Such a work, in isolation, is not a derivative work of the Library, and therefore falls outside the scope of this License.
However, linking a “work that uses the Library” with the Library creates an executable that is a derivative of the Library (because it contains portions of the Library), rather than a “work that uses the library”. The executable is therefore covered by this License. Section 6 states terms for distribution of such executables.
When a “work that uses the Library” uses material from a header ﬁle that is part of the Library, the object code for the work may be a derivative work of the Library even though the source code is not. Whether this is true is especially signiﬁcant if the work can be linked without the Library, or if the work is itself a library. The threshold for this to be true is not precisely deﬁned by law.
If such an object ﬁle uses only numerical parameters, data structure layouts and accessors, and small macros and small inline functions (ten lines or less in length), then the use of the object ﬁle is unrestricted, regardless of whether it is legally a derivative work. (Executables containing this object code plus portions of the Library will still fall under Section 6.) Otherwise, if the work is a derivative of the Library, you may distribute the object code for the work under the terms of
Section 6. Any executables containing that work also fall under Section 6, whether or not they are linked directly with the Library itself.
6. As an exception to the Sections above, you may also combine or link a “work that uses the
Library” with the Library to produce a work containing portions of the Library, and distribute that work under terms of your choice, provided that the terms permit modiﬁcation of the work for the customer’s own use and reverse engineering for debugging such modiﬁcations.
You must give prominent notice with each copy of the work that the Library is used in it and that the Library and its use are covered by this License. You must supply a copy of this License.
If the work during execution displays copyright notices, you must include the copyright notice for the Library among them, as well as a reference directing the user to the copy of this License.
Also, you must do one of these things:
a) Accompany the work with the complete corresponding machine-readable source code for the Library including whatever changes were used in the work (which must be distributed under
Sections 1 and 2 above); and, if the work is an executable linked with the Library, with the complete machine-readable “work that uses the Library”, as object code and/or source code, so that the user can modify the Library and then relink to produce a modiﬁed executable containing the modiﬁed Library. (It is understood that the user who changes the contents of deﬁnitions ﬁles in the Library will not necessarily be able to recompile the application to use the modiﬁed deﬁnitions.) b) Use a suitable shared library mechanism for linking with the Library. A suitable mechanism is one that (1) uses at run time a copy of the library already present on the user’s computer system, rather than copying library functions into the executable, and (2) will operate properly with a modiﬁed version of the library, if the user installs one, as long as the modiﬁed version is interface-compatible with the version that the work was made with.
c) Accompany the work with a written offer, valid for at least three years, to give the same user the materials speciﬁed in Subsection 6a, above, for a charge no more than the cost of performing this distribution.
d) If distribution of the work is made by offering access to copy from a designated place, offer equivalent access to copy the above speciﬁed materials from the same place.
e) Verify that the user has already received a copy of these materials or that you have already sent this user a copy.
For an executable, the required form of the “work that uses the Library” must include any data and utility programs needed for reproducing the executable from it. However, as a special exception, the materials to be distributed need not include anything that is normally distributed
(in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable. 284

16 Third-party materials and licenses
It may happen that this requirement contradicts the license restrictions of other proprietary libraries that do not normally accompany the operating system. Such a contradiction means you cannot use both them and the Library together in an executable that you distribute.
7. You may place library facilities that are a work based on the Library side-by-side in a single library together with other library facilities not covered by this License, and distribute such a combined library, provided that the separate distribution of the work based on the Library and of the other library facilities is otherwise permitted, and provided that you do these two things:
a) Accompany the combined library with a copy of the same work based on the Library, uncombined with any other library facilities. This must be distributed under the terms of the Sections above. b) Give prominent notice with the combined library of the fact that part of it is a work based on the Library, and explaining where to ﬁnd the accompanying uncombined form of the same work. 8. You may not copy, modify, sublicense, link with, or distribute the Library except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense, link with, or distribute the Library is void, and will automatically terminate your rights under this License.
However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.
9. You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Library or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Library (or any work based on the Library), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the
Library or works based on it.
10. Each time you redistribute the Library (or any work based on the Library), the recipient automatically receives a license from the original licensor to copy, distribute, link with or modify the Library subject to these terms and conditions. You may not impose any further restrictions on the recipients’ exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties with this License.
11. If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Library at all. For example, if a patent license would not permit royalty-free redistribution of the Library by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Library.
If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply, and the section as a whole is intended to apply in other circumstances.
It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice.
This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.
12. If the distribution and/or use of the Library is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Library under this License may add an explicit geographical distribution limitation excluding those countries,

285

16 Third-party materials and licenses so that distribution is permitted only in or among countries not thus excluded. In such case, this
License incorporates the limitation as if written in the body of this License.
13. The Free Software Foundation may publish revised and/or new versions of the Lesser
General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.
Each version is given a distinguishing version number. If the Library speciﬁes a version number of this License which applies to it and “any later version”, you have the option of following the terms and conditions either of that version or of any later version published by the Free Software
Foundation. If the Library does not specify a license version number, you may choose any version ever published by the Free Software Foundation.
14. If you wish to incorporate parts of the Library into other free programs whose distribution conditions are incompatible with these, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally.
NO WARRANTY
15. BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR
THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE
THE LIBRARY “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE LIBRARY IS WITH YOU. SHOULD THE LIBRARY PROVE DEFECTIVE, YOU
ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
16. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE LIBRARY AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF
THE USE OR INABILITY TO USE THE LIBRARY (INCLUDING BUT NOT LIMITED TO LOSS OF
DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN
IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES.
END OF TERMS AND CONDITIONS

16.2.3 Mozilla Public License (MPL)
MOZILLA PUBLIC LICENSE Version 1.1
1. Deﬁnitions.
1.0.1. “Commercial Use” means distribution or otherwise making the Covered Code available to a third party.
1.1. “Contributor” means each entity that creates or contributes to the creation of Modiﬁcations.
1.2. “Contributor Version” means the combination of the Original Code, prior Modiﬁcations used by a Contributor, and the Modiﬁcations made by that particular Contributor.
1.3. “Covered Code” means the Original Code or Modiﬁcations or the combination of the
Original Code and Modiﬁcations, in each case including portions thereof.
1.4. “Electronic Distribution Mechanism” means a mechanism generally accepted in the software development community for the electronic transfer of data.
1.5. “Executable” means Covered Code in any form other than Source Code.
1.6. “Initial Developer” means the individual or entity identiﬁed as the Initial Developer in the
Source Code notice required by Exhibit A.

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16 Third-party materials and licenses
1.7. “Larger Work” means a work which combines Covered Code or portions thereof with code not governed by the terms of this License.
1.8. “License” means this document.
1.8.1. “Licensable” means having the right to grant, to the maximum extent possible, whether at the time of the initial grant or subsequently acquired, any and all of the rights conveyed herein.
1.9. “Modiﬁcations” means any addition to or deletion from the substance or structure of either the Original Code or any previous Modiﬁcations. When Covered Code is released as a series of ﬁles, a Modiﬁcation is:
A. Any addition to or deletion from the contents of a ﬁle containing Original Code or previous
Modiﬁcations.
B. Any new ﬁle that contains any part of the Original Code or previous Modiﬁcations.
1.10. “Original Code” means Source Code of computer software code which is described in the
Source Code notice required by Exhibit A as Original Code, and which, at the time of its release under this License is not already Covered Code governed by this License.
1.10.1. “Patent Claims” means any patent claim(s), now owned or hereafter acquired, including without limitation, method, process, and apparatus claims, in any patent Licensable by grantor. 1.11. “Source Code” means the preferred form of the Covered Code for making modiﬁcations to it, including all modules it contains, plus any associated interface deﬁnition ﬁles, scripts used to control compilation and installation of an Executable, or source code differential comparisons against either the Original Code or another well known, available Covered Code of the Contributor’s choice. The Source Code can be in a compressed or archival form, provided the appropriate decompression or de-archiving software is widely available for no charge.
1.12. “You” (or “Your”) means an individual or a legal entity exercising rights under, and complying with all of the terms of, this License or a future version of this License issued under
Section 6.1. For legal entities, “You” includes any entity which controls, is controlled by, or is under common control with You. For purposes of this deﬁnition, “control” means (a) the power, direct or indirect, to cause the direction or management of such entity, whether by contract or otherwise, or (b) ownership of more than ﬁfty percent (50%) of the outstanding shares or beneﬁcial ownership of such entity.
2. Source Code License.
2.1. The Initial Developer Grant. The Initial Developer hereby grants You a world-wide, royalty-free, non-exclusive license, subject to third party intellectual property claims:
(a) under intellectual property rights (other than patent or trademark) Licensable by Initial
Developer to use, reproduce, modify, display, perform, sublicense and distribute the Original
Code (or portions thereof) with or without Modiﬁcations, and/or as part of a Larger Work; and
(b) under Patents Claims infringed by the making, using or selling of Original Code, to make, have made, use, practice, sell, and offer for sale, and/or otherwise dispose of the Original Code
(or portions thereof).
(c) the licenses granted in this Section 2.1(a) and (b) are effective on the date Initial Developer ﬁrst distributes Original Code under the terms of this License.
(d) Notwithstanding Section 2.1(b) above, no patent license is granted: 1) for code that You delete from the Original Code; 2) separate from the Original Code; or 3) for infringements caused by: i) the modiﬁcation of the Original Code or ii) the combination of the Original Code with other software or devices.
2.2. Contributor Grant. Subject to third party intellectual property claims, each Contributor hereby grants You a world-wide, royalty-free, non-exclusive license
(a) under intellectual property rights (other than patent or trademark) Licensable by Contributor, to use, reproduce, modify, display, perform, sublicense and distribute the Modiﬁcations created by such Contributor (or portions thereof) either on an unmodiﬁed basis, with other
Modiﬁcations, as Covered Code and/or as part of a Larger Work; and
(b) under Patent Claims infringed by the making, using, or selling of Modiﬁcations made by that Contributor either alone and/or in combination with its Contributor Version (or portions

287

16 Third-party materials and licenses of such combination), to make, use, sell, offer for sale, have made, and/or otherwise dispose of: 1) Modiﬁcations made by that Contributor (or portions thereof); and 2) the combination of Modiﬁcations made by that Contributor with its Contributor Version (or portions of such combination). (c) the licenses granted in Sections 2.2(a) and 2.2(b) are effective on the date Contributor ﬁrst makes Commercial Use of the Covered Code.
(d) Notwithstanding Section 2.2(b) above, no patent license is granted: 1) for any code that
Contributor has deleted from the Contributor Version; 2) separate from the Contributor Version;
3) for infringements caused by: i) third party modiﬁcations of Contributor Version or ii) the combination of Modiﬁcations made by that Contributor with other software (except as part of the Contributor Version) or other devices; or 4) under Patent Claims infringed by Covered Code in the absence of Modiﬁcations made by that Contributor.
3. Distribution Obligations.
3.1. Application of License. The Modiﬁcations which You create or to which You contribute are governed by the terms of this License, including without limitation Section 2.2. The Source
Code version of Covered Code may be distributed only under the terms of this License or a future version of this License released under Section 6.1, and You must include a copy of this
License with every copy of the Source Code You distribute. You may not offer or impose any terms on any Source Code version that alters or restricts the applicable version of this License or the recipients’ rights hereunder. However, You may include an additional document offering the additional rights described in Section 3.5.
3.2. Availability of Source Code. Any Modiﬁcation which You create or to which You contribute must be made available in Source Code form under the terms of this License either on the same media as an Executable version or via an accepted Electronic Distribution Mechanism to anyone to whom you made an Executable version available; and if made available via Electronic
Distribution Mechanism, must remain available for at least twelve (12) months after the date it initially became available, or at least six (6) months after a subsequent version of that particular Modiﬁcation has been made available to such recipients. You are responsible for ensuring that the Source Code version remains available even if the Electronic Distribution Mechanism is maintained by a third party.
3.3. Description of Modiﬁcations. You must cause all Covered Code to which You contribute to contain a ﬁle documenting the changes You made to create that Covered Code and the date of any change. You must include a prominent statement that the Modiﬁcation is derived, directly or indirectly, from Original Code provided by the Initial Developer and including the name of the Initial Developer in (a) the Source Code, and (b) in any notice in an Executable version or related documentation in which You describe the origin or ownership of the Covered Code.
3.4. Intellectual Property Matters
(a) Third Party Claims. If Contributor has knowledge that a license under a third party’s intellectual property rights is required to exercise the rights granted by such Contributor under
Sections 2.1 or 2.2, Contributor must include a text ﬁle with the Source Code distribution titled
“LEGAL” which describes the claim and the party making the claim in sufﬁcient detail that a recipient will know whom to contact. If Contributor obtains such knowledge after the Modiﬁcation is made available as described in Section 3.2, Contributor shall promptly modify the LEGAL ﬁle in all copies Contributor makes available thereafter and shall take other steps (such as notifying appropriate mailing lists or newsgroups) reasonably calculated to inform those who received the
Covered Code that new knowledge has been obtained.
(b) Contributor APIs. If Contributor’s Modiﬁcations include an application programming interface and Contributor has knowledge of patent licenses which are reasonably necessary to implement that API, Contributor must also include this information in the LEGAL ﬁle.
3.5. Required Notices. You must duplicate the notice in Exhibit A in each ﬁle of the Source
Code. If it is not possible to put such notice in a particular Source Code ﬁle due to its structure, then You must include such notice in a location (such as a relevant directory) where a user would be likely to look for such a notice. If You created one or more Modiﬁcation(s) You may add your

288

16 Third-party materials and licenses name as a Contributor to the notice described in Exhibit A. You must also duplicate this License in any documentation for the Source Code where You describe recipients’ rights or ownership rights relating to Covered Code. You may choose to offer, and to charge a fee for, warranty, support, indemnity or liability obligations to one or more recipients of Covered Code. However, You may do so only on Your own behalf, and not on behalf of the Initial Developer or any Contributor. You must make it absolutely clear than any such warranty, support, indemnity or liability obligation is offered by You alone, and You hereby agree to indemnify the Initial Developer and every
Contributor for any liability incurred by the Initial Developer or such Contributor as a result of warranty, support, indemnity or liability terms You offer.
3.6. Distribution of Executable Versions. You may distribute Covered Code in Executable form only if the requirements of Section 3.1-3.5 have been met for that Covered Code, and if You include a notice stating that the Source Code version of the Covered Code is available under the terms of this License, including a description of how and where You have fulﬁlled the obligations of Section 3.2. The notice must be conspicuously included in any notice in an
Executable version, related documentation or collateral in which You describe recipients’ rights relating to the Covered Code. You may distribute the Executable version of Covered Code or ownership rights under a license of Your choice, which may contain terms different from this
License, provided that You are in compliance with the terms of this License and that the license for the Executable version does not attempt to limit or alter the recipient’s rights in the Source
Code version from the rights set forth in this License. If You distribute the Executable version under a different license You must make it absolutely clear that any terms which differ from this
License are offered by You alone, not by the Initial Developer or any Contributor. You hereby agree to indemnify the Initial Developer and every Contributor for any liability incurred by the
Initial Developer or such Contributor as a result of any such terms You offer.
3.7. Larger Works. You may create a Larger Work by combining Covered Code with other code not governed by the terms of this License and distribute the Larger Work as a single product. In such a case, You must make sure the requirements of this License are fulﬁlled for the Covered
Code.
4. Inability to Comply Due to Statute or Regulation.If it is impossible for You to comply with any of the terms of this License with respect to some or all of the Covered Code due to statute, judicial order, or regulation then You must: (a) comply with the terms of this License to the maximum extent possible; and (b) describe the limitations and the code they affect. Such description must be included in the LEGAL ﬁle described in Section 3.4 and must be included with all distributions of the Source Code. Except to the extent prohibited by statute or regulation, such description must be sufﬁciently detailed for a recipient of ordinary skill to be able to understand it. 5. Application of this License. This License applies to code to which the Initial Developer has attached the notice in Exhibit A and to related Covered Code.
6. Versions of the License.
6.1. New Versions. Netscape Communications Corporation (“Netscape”) may publish revised and/or new versions of the License from time to time. Each version will be given a distinguishing version number.
6.2. Effect of New Versions. Once Covered Code has been published under a particular version of the License, You may always continue to use it under the terms of that version. You may also choose to use such Covered Code under the terms of any subsequent version of the License published by Netscape. No one other than Netscape has the right to modify the terms applicable to Covered Code created under this License.
6.3. Derivative Works. If You create or use a modiﬁed version of this License (which you may only do in order to apply it to code which is not already Covered Code governed by this License), You must (a) rename Your license so that the phrases “Mozilla”, “MOZILLAPL”, “MOZPL”,
“Netscape”, “MPL”, “NPL” or any confusingly similar phrase do not appear in your license (except to note that your license differs from this License) and (b) otherwise make it clear that Your version of the license contains terms which differ from the Mozilla Public License and Netscape

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16 Third-party materials and licenses
Public License. (Filling in the name of the Initial Developer, Original Code or Contributor in the notice described in Exhibit A shall not of themselves be deemed to be modiﬁcations of this
License.)
7. DISCLAIMER OF WARRANTY.
COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN “AS IS” BASIS, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION,
WARRANTIES THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A
PARTICULAR PURPOSE OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND
PERFORMANCE OF THE COVERED CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE
DEFECTIVE IN ANY RESPECT, YOU (NOT THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY SERVICING, REPAIR OR CORRECTION. THIS
DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. NO USE
OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER THIS DISCLAIMER.
8. TERMINATION.
8.1. This License and the rights granted hereunder will terminate automatically if You fail to comply with terms herein and fail to cure such breach within 30 days of becoming aware of the breach. All sublicenses to the Covered Code which are properly granted shall survive any termination of this License. Provisions which, by their nature, must remain in effect beyond the termination of this License shall survive.
8.2. If You initiate litigation by asserting a patent infringement claim (excluding declaratory judgment actions) against Initial Developer or a Contributor (the Initial Developer or Contributor against whom You ﬁle such action is referred to as “Participant”) alleging that:
(a) such Participant’s Contributor Version directly or indirectly infringes any patent, then any and all rights granted by such Participant to You under Sections 2.1 and/or 2.2 of this License shall, upon 60 days notice from Participant terminate prospectively, unless if within 60 days after receipt of notice You either: (i) agree in writing to pay Participant a mutually agreeable reasonable royalty for Your past and future use of Modiﬁcations made by such Participant, or (ii) withdraw Your litigation claim with respect to the Contributor Version against such Participant.
If within 60 days of notice, a reasonable royalty and payment arrangement are not mutually agreed upon in writing by the parties or the litigation claim is not withdrawn, the rights granted by Participant to You under Sections 2.1 and/or 2.2 automatically terminate at the expiration of the 60 day notice period speciﬁed above.
(b) any software, hardware, or device, other than such Participant’s Contributor Version, directly or indirectly infringes any patent, then any rights granted to You by such Participant under
Sections 2.1(b) and 2.2(b) are revoked effective as of the date You ﬁrst made, used, sold, distributed, or had made, Modiﬁcations made by that Participant.
8.3. If You assert a patent infringement claim against Participant alleging that such Participant’s Contributor Version directly or indirectly infringes any patent where such claim is resolved
(such as by license or settlement) prior to the initiation of patent infringement litigation, then the reasonable value of the licenses granted by such Participant under Sections 2.1 or 2.2 shall be taken into account in determining the amount or value of any payment or license.
8.4. In the event of termination under Sections 8.1 or 8.2 above, all end user license agreements (excluding distributors and resellers) which have been validly granted by You or any distributor hereunder prior to termination shall survive termination.
9. LIMITATION OF LIABILITY. UNDER NO CIRCUMSTANCES AND UNDER NO LEGAL THEORY, WHETHER TORT (INCLUDING NEGLIGENCE), CONTRACT, OR OTHERWISE, SHALL YOU,
THE INITIAL DEVELOPER, ANY OTHER CONTRIBUTOR, OR ANY DISTRIBUTOR OF COVERED
CODE, OR ANY SUPPLIER OF ANY OF SUCH PARTIES, BE LIABLE TO ANY PERSON FOR ANY
INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OF ANY CHARACTER INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF GOODWILL, WORK STOPPAGE,
COMPUTER FAILURE OR MALFUNCTION, OR ANY AND ALL OTHER COMMERCIAL DAMAGES OR LOSSES, EVEN IF SUCH PARTY SHALL HAVE BEEN INFORMED OF THE POSSIBILITY
OF SUCH DAMAGES. THIS LIMITATION OF LIABILITY SHALL NOT APPLY TO LIABILITY FOR

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16 Third-party materials and licenses
DEATH OR PERSONAL INJURY RESULTING FROM SUCH PARTY’S NEGLIGENCE TO THE EXTENT APPLICABLE LAW PROHIBITS SUCH LIMITATION. SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO
THIS EXCLUSION AND LIMITATION MAY NOT APPLY TO YOU.
10. U.S. GOVERNMENT END USERS. The Covered Code is a “commercial item,“ as that term is deﬁned in 48 C.F.R. 2.101 (Oct. 1995), consisting of “commercial computer software” and
“commercial computer software documentation,“ as such terms are used in 48 C.F.R. 12.212
(Sept. 1995). Consistent with 48 C.F.R. 12.212 and 48 C.F.R. 227.7202-1 through 227.7202-4
(June 1995), all U.S. Government End Users acquire Covered Code with only those rights set forth herein.
11. MISCELLANEOUS. This License represents the complete agreement concerning subject matter hereof. If any provision of this License is held to be unenforceable, such provision shall be reformed only to the extent necessary to make it enforceable. This License shall be governed by California law provisions (except to the extent applicable law, if any, provides otherwise), excluding its conﬂict-of-law provisions. With respect to disputes in which at least one party is a citizen of, or an entity chartered or registered to do business in the United States of America, any litigation relating to this License shall be subject to the jurisdiction of the Federal Courts of the Northern District of California, with venue lying in Santa Clara County, California, with the losing party responsible for costs, including without limitation, court costs and reasonable attorneys’ fees and expenses. The application of the United Nations Convention on Contracts for the International Sale of Goods is expressly excluded. Any law or regulation which provides that the language of a contract shall be construed against the drafter shall not apply to this License.
12. RESPONSIBILITY FOR CLAIMS. As between Initial Developer and the Contributors, each party is responsible for claims and damages arising, directly or indirectly, out of its utilization of rights under this License and You agree to work with Initial Developer and Contributors to distribute such responsibility on an equitable basis. Nothing herein is intended or shall be deemed to constitute any admission of liability.
13. MULTIPLE-LICENSED CODE. Initial Developer may designate portions of the Covered
Code as “Multiple-Licensed”. “Multiple-Licensed” means that the Initial Developer permits you to utilize portions of the Covered Code under Your choice of the NPL or the alternative licenses, if any, speciﬁed by the Initial Developer in the ﬁle described in Exhibit A.
EXHIBIT A -Mozilla Public License.
“The contents of this ﬁle are subject to the Mozilla Public License Version 1.1 (the “License”); you may not use this ﬁle except in compliance with the License. You may obtain a copy of the
License at http://www.mozilla.org/MPL/
Software distributed under the License is distributed on an “AS IS” basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the speciﬁc language governing rights and limitations under the License.
The Original Code is ______________________________________.
The Initial Developer of the Original Code is ________________________. Portions created by ______________________ are Copyright (C) ______ _______________________. All Rights
Reserved.
Contributor(s): ______________________________________.
Alternatively, the contents of this ﬁle may be used under the terms of the _____ license (the
“[___] License”), in which case the provisions of [______] License are applicable instead of those above. If you wish to allow use of your version of this ﬁle only under the terms of the [____]
License and not to allow others to use your version of this ﬁle under the MPL, indicate your decision by deleting the provisions above and replace them with the notice and other provisions required by the [___] License. If you do not delete the provisions above, a recipient may use your version of this ﬁle under either the MPL or the [___] License.“
[NOTE: The text of this Exhibit A may differ slightly from the text of the notices in the Source
Code ﬁles of the Original Code. You should use the text of this Exhibit A rather than the text found in the Original Code Source Code for Your Modiﬁcations.]

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16 Third-party materials and licenses

16.2.4 MIT License
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation ﬁles (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

16.2.5 X Consortium License (X11)
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation ﬁles (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

16.2.6 zlib license
This software is provided ’as-is’, without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
Jean-loup Gailly jloup@gzip.org Mark Adler madler@alumni.caltech.edu 16.2.7 OpenSSL license
This package is an SSL implementation written by Eric Young (eay@cryptsoft.com). The implementation was written so as to conform with Netscape’s SSL.

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16 Third-party materials and licenses
This library is free for commercial and non-commercial use as long as the following conditions are adhered to. The following conditions apply to all code found in this distribution, be it the
RC4, RSA, lhash, DES, etc., code; not just the SSL code. The SSL documentation included with this distribution is covered by the same copyright terms except that the holder is Tim Hudson
(tjh@cryptsoft.com).
Copyright remains Eric Young’s, and as such any Copyright notices in the code are not to be removed. If this package is used in a product, Eric Young should be given attribution as the author of the parts of the library used. This can be in the form of a textual message at program startup or in documentation (online or textual) provided with the package.
Redistribution and use in source and binary forms, with or without modiﬁcation, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. All advertising materials mentioning features or use of this software must display the following acknowledgement: “This product includes cryptographic software written by Eric Young
(eay@cryptsoft.com)“ The word ’cryptographic’ can be left out if the routines from the library being used are not cryptographic related :-).
4. If you include any Windows speciﬁc code (or a derivative thereof) from the apps directory (application code) you must include an acknowledgement: “This product includes software written by Tim Hudson (tjh@cryptsoft.com)“
THIS SOFTWARE IS PROVIDED BY ERIC YOUNG “AS IS” AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
THE POSSIBILITY OF SUCH DAMAGE.
The licence and distribution terms for any publicly available version or derivative of this code cannot be changed. i.e. this code cannot simply be copied and put under another distribution licence [including the GNU Public Licence.]

16.2.8 Slirp license
Copyright (c) 1995,1996 Danny Gasparovski. All rights reserved.
Redistribution and use in source and binary forms, with or without modiﬁcation, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. All advertising materials mentioning features or use of this software must display the following acknowledgment: This product includes software developed by Danny Gasparovski.
THIS SOFTWARE IS PROVIDED “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DANNY GASPAROVSKI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-

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16 Third-party materials and licenses
CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
THE POSSIBILITY OF SUCH DAMAGE.

16.2.9 liblzf license
Redistribution and use in source and binary forms, with or without modiﬁcation, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products derived from this software without speciﬁc prior written permission.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR “AS IS” AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.

16.2.10 libpng license
The PNG Reference Library is supplied “AS IS”. The Contributing Authors and Group 42, Inc. disclaim all warranties, expressed or implied, including, without limitation, the warranties of merchantability and of ﬁtness for any purpose. The Contributing Authors and Group 42, Inc. assume no liability for direct, indirect, incidental, special, exemplary, or consequential damages, which may result from the use of the PNG Reference Library, even if advised of the possibility of such damage.
Permission is hereby granted to use, copy, modify, and distribute this source code, or portions hereof, for any purpose, without fee, subject to the following restrictions:
1. The origin of this source code must not be misrepresented.
2. Altered versions must be plainly marked as such and must not be misrepresented as being the original source.
3. This Copyright notice may not be removed or altered from any source or altered source distribution. The Contributing Authors and Group 42, Inc. speciﬁcally permit, without fee, and encourage the use of this source code as a component to supporting the PNG ﬁle format in commercial products. If you use this source code in a product, acknowledgment is not required but would be appreciated.

16.2.11 lwIP license
Redistribution and use in source and binary forms, with or without modiﬁcation, are permitted provided that the following conditions are met:

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16 Third-party materials and licenses
1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products derived from this software without speciﬁc prior written permission.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR “AS IS” AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.

16.2.12 libxml license
Except where otherwise noted in the source code (e.g. the ﬁles hash.c, list.c and the trio ﬁles, which are covered by a similar licence but with different Copyright notices) all the ﬁles are:
Copyright (C) 1998-2003 Daniel Veillard. All Rights Reserved.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation ﬁles (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
DANIEL VEILLARD BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Except as contained in this notice, the name of Daniel Veillard shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from him.

16.2.13 libxslt licenses
Licence for libxslt except libexslt:
Copyright (C) 2001-2002 Daniel Veillard. All Rights Reserved.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation ﬁles (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

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16 Third-party materials and licenses
DANIEL VEILLARD BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Except as contained in this notice, the name of Daniel Veillard shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from him.
Licence for libexslt:
Copyright (C) 2001-2002 Thomas Broyer, Charlie Bozeman and Daniel Veillard. All Rights
Reserved.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation ﬁles (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Except as contained in this notice, the name of the authors shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from him.

16.2.14 gSOAP Public License Version 1.3a
The gSOAP public license is derived from the Mozilla Public License (MPL1.1). The sections that were deleted from the original MPL1.1 text are 1.0.1, 2.1.(c),(d), 2.2.(c),(d), 8.2.(b), 10, and 11. Section 3.8 was added. The modiﬁed sections are 2.1.(b), 2.2.(b), 3.2 (simpliﬁed), 3.5
(deleted the last sentence), and 3.6 (simpliﬁed).
1 DEFINITIONS
1.1. “Contributor” means each entity that creates or contributes to the creation of Modiﬁcations.
1.2. “Contributor Version” means the combination of the Original Code, prior Modiﬁcations used by a Contributor, and the Modiﬁcations made by that particular Contributor.
1.3. “Covered Code” means the Original Code, or Modiﬁcations or the combination of the
Original Code, and Modiﬁcations, in each case including portions thereof.
1.4. “Electronic Distribution Mechanism” means a mechanism generally accepted in the software development community for the electronic transfer of data.
1.5. “Executable” means Covered Code in any form other than Source Code.
1.6. “Initial Developer” means the individual or entity identiﬁed as the Initial Developer in the
Source Code notice required by Exhibit A.
1.7. “Larger Work” means a work which combines Covered Code or portions thereof with code not governed by the terms of this License.
1.8. “License” means this document.
1.8.1. “Licensable” means having the right to grant, to the maximum extent possible, whether at the time of the initial grant or subsequently acquired, any and all of the rights conveyed herein.
1.9. “Modiﬁcations” means any addition to or deletion from the substance or structure of either the Original Code or any previous Modiﬁcations. When Covered Code is released as a series of ﬁles, a Modiﬁcation is:

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A. Any addition to or deletion from the contents of a ﬁle containing Original Code or previous
Modiﬁcations.
B. Any new ﬁle that contains any part of the Original Code, or previous Modiﬁcations.
1.10. “Original Code” means Source Code of computer software code which is described in the
Source Code notice required by Exhibit A as Original Code, and which, at the time of its release under this License is not already Covered Code governed by this License.
1.10.1. “Patent Claims” means any patent claim(s), now owned or hereafter acquired, including without limitation, method, process, and apparatus claims, in any patent Licensable by grantor. 1.11. “Source Code” means the preferred form of the Covered Code for making modiﬁcations to it, including all modules it contains, plus any associated interface deﬁnition ﬁles, scripts used to control compilation and installation of an Executable, or source code differential comparisons against either the Original Code or another well known, available Covered Code of the Contributor’s choice. The Source Code can be in a compressed or archival form, provided the appropriate decompression or de-archiving software is widely available for no charge.
1.12. “You” (or “Your”) means an individual or a legal entity exercising rights under, and complying with all of the terms of, this License or a future version of this License issued under
Section 6.1. For legal entities, “You” includes any entity which controls, is controlled by, or is under common control with You. For purposes of this deﬁnition, “control” means (a) the power, direct or indirect, to cause the direction or management of such entity, whether by contract or otherwise, or (b) ownership of more than ﬁfty percent (50%) of the outstanding shares or beneﬁcial ownership of such entity.
2 SOURCE CODE LICENSE.
2.1. The Initial Developer Grant.
The Initial Developer hereby grants You a world-wide, royalty-free, non-exclusive license, subject to third party intellectual property claims:
(a) under intellectual property rights (other than patent or trademark) Licensable by Initial
Developer to use, reproduce, modify, display, perform, sublicense and distribute the Original
Code (or portions thereof) with or without Modiﬁcations, and/or as part of a Larger Work; and
(b) under patents now or hereafter owned or controlled by Initial Developer, to make, have made, use and sell (“offer to sell and import”) the Original Code, Modiﬁcations, or portions thereof, but solely to the extent that any such patent is reasonably necessary to enable You to utilize, alone or in combination with other software, the Original Code, Modiﬁcations, or any combination or portions thereof.
(c)
(d)
2.2. Contributor Grant.
Subject to third party intellectual property claims, each Contributor hereby grants You a worldwide, royalty-free, non-exclusive license
(a) under intellectual property rights (other than patent or trademark) Licensable by Contributor, to use, reproduce, modify, display, perform, sublicense and distribute the Modiﬁcations created by such Contributor (or portions thereof) either on an unmodiﬁed basis, with other
Modiﬁcations, as Covered Code and/or as part of a Larger Work; and
(b) under patents now or hereafter owned or controlled by Contributor, to make, have made, use and sell (“offer to sell and import”) the Contributor Version (or portions thereof), but solely to the extent that any such patent is reasonably necessary to enable You to utilize, alone or in combination with other software, the Contributor Version (or portions thereof).
(c)
(d)
3 DISTRIBUTION OBLIGATIONS.
3.1. Application of License.
The Modiﬁcations which You create or to which You contribute are governed by the terms of this License, including without limitation Section 2.2. The Source Code version of Covered

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Code may be distributed only under the terms of this License or a future version of this License released under Section 6.1, and You must include a copy of this License with every copy of the
Source Code You distribute. You may not offer or impose any terms on any Source Code version that alters or restricts the applicable version of this License or the recipients’ rights hereunder.
However, You may include an additional document offering the additional rights described in
Section 3.5.
3.2. Availability of Source Code.
Any Modiﬁcation created by You will be provided to the Initial Developer in Source Code form and are subject to the terms of the License. 3.3. Description of Modiﬁcations.
You must cause all Covered Code to which You contribute to contain a ﬁle documenting the changes You made to create that Covered Code and the date of any change. You must include a prominent statement that the Modiﬁcation is derived, directly or indirectly, from Original Code provided by the Initial Developer and including the name of the Initial Developer in (a) the
Source Code, and (b) in any notice in an Executable version or related documentation in which
You describe the origin or ownership of the Covered Code.
3.4. Intellectual Property Matters.
(a) Third Party Claims. If Contributor has knowledge that a license under a third party’s intellectual property rights is required to exercise the rights granted by such Contributor under
Sections 2.1 or 2.2, Contributor must include a text ﬁle with the Source Code distribution titled
“LEGAL” which describes the claim and the party making the claim in sufﬁcient detail that a recipient will know whom to contact. If Contributor obtains such knowledge after the Modiﬁcation is made available as described in Section 3.2, Contributor shall promptly modify the LEGAL ﬁle in all copies Contributor makes available thereafter and shall take other steps (such as notifying appropriate mailing lists or newsgroups) reasonably calculated to inform those who received the
Covered Code that new knowledge has been obtained.
(b) Contributor APIs. If Contributor’s Modiﬁcations include an application programming interface and Contributor has knowledge of patent licenses which are reasonably necessary to implement that API, Contributor must also include this information in the LEGAL ﬁle.
(c) Representations. Contributor represents that, except as disclosed pursuant to Section
3.4(a) above, Contributor believes that Contributor’s Modiﬁcations are Contributor’s original creation(s) and/or Contributor has sufﬁcient rights to grant the rights conveyed by this License.
3.5. Required Notices. You must duplicate the notice in Exhibit A in each ﬁle of the Source
Code. If it is not possible to put such notice in a particular Source Code ﬁle due to its structure, then You must include such notice in a location (such as a relevant directory) where a user would be likely to look for such a notice. If You created one or more Modiﬁcation(s) You may add your name as a Contributor to the notice described in Exhibit A. You must also duplicate this License in any documentation for the Source Code where You describe recipients’ rights or ownership rights relating to Covered Code. You may choose to offer, and to charge a fee for, warranty, support, indemnity or liability obligations to one or more recipients of Covered Code. However, You may do so only on Your own behalf, and not on behalf of the Initial Developer or any Contributor.
3.6. Distribution of Executable Versions. You may distribute Covered Code in Executable form only if the requirements of Section 3.1-3.5 have been met for that Covered Code. You may distribute the Executable version of Covered Code or ownership rights under a license of Your choice, which may contain terms different from this License, provided that You are in compliance with the terms of this License and that the license for the Executable version does not attempt to limit or alter the recipient’s rights in the Source Code version from the rights set forth in this License. If You distribute the Executable version under a different license You must make it absolutely clear that any terms which differ from this License are offered by You alone, not by the
Initial Developer or any Contributor. If you distribute executable versions containing Covered
Code as part of a product, you must reproduce the notice in Exhibit B in the documentation and/or other materials provided with the product.
3.7. Larger Works. You may create a Larger Work by combining Covered Code with other code not governed by the terms of this License and distribute the Larger Work as a single product. In

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16 Third-party materials and licenses such a case, You must make sure the requirements of this License are fulﬁlled for the Covered
Code.
3.8. Restrictions. You may not remove any product identiﬁcation, copyright, proprietary notices or labels from gSOAP.
4 INABILITY TO COMPLY DUE TO STATUTE OR REGULATION.
If it is impossible for You to comply with any of the terms of this License with respect to some or all of the Covered Code due to statute, judicial order, or regulation then You must: (a) comply with the terms of this License to the maximum extent possible; and (b) describe the limitations and the code they affect. Such description must be included in the LEGAL ﬁle described in
Section 3.4 and must be included with all distributions of the Source Code. Except to the extent prohibited by statute or regulation, such description must be sufﬁciently detailed for a recipient of ordinary skill to be able to understand it.
5 APPLICATION OF THIS LICENSE.
This License applies to code to which the Initial Developer has attached the notice in Exhibit
A and to related Covered Code.
6 VERSIONS OF THE LICENSE.
6.1. New Versions.
Grantor may publish revised and/or new versions of the License from time to time. Each version will be given a distinguishing version number.
6.2. Effect of New Versions.
Once Covered Code has been published under a particular version of the License, You may always continue to use it under the terms of that version. You may also choose to use such
Covered Code under the terms of any subsequent version of the License.
6.3. Derivative Works.
If You create or use a modiﬁed version of this License (which you may only do in order to apply it to code which is not already Covered Code governed by this License), You must (a) rename
Your license so that the phrase “gSOAP” or any confusingly similar phrase do not appear in your license (except to note that your license differs from this License) and (b) otherwise make it clear that Your version of the license contains terms which differ from the gSOAP Public License.
(Filling in the name of the Initial Developer, Original Code or Contributor in the notice described in Exhibit A shall not of themselves be deemed to be modiﬁcations of this License.)
7 DISCLAIMER OF WARRANTY.
COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN “AS IS” BASIS, WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, WITHOUT
LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY, OF FITNESS FOR A PARTICULAR PURPOSE, NONINFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY RIGHTS,
AND ANY WARRANTY THAT MAY ARISE BY REASON OF TRADE USAGE, CUSTOM, OR COURSE
OF DEALING. WITHOUT LIMITING THE FOREGOING, YOU ACKNOWLEDGE THAT THE SOFTWARE IS PROVIDED “AS IS” AND THAT THE AUTHORS DO NOT WARRANT THE SOFTWARE
WILL RUN UNINTERRUPTED OR ERROR FREE. LIMITED LIABILITY THE ENTIRE RISK AS
TO RESULTS AND PERFORMANCE OF THE SOFTWARE IS ASSUMED BY YOU. UNDER NO
CIRCUMSTANCES WILL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES OF ANY KIND OR NATURE WHATSOEVER,
WHETHER BASED ON CONTRACT, WARRANTY, TORT (INCLUDING NEGLIGENCE), STRICT
LIABILITY OR OTHERWISE, ARISING OUT OF OR IN ANY WAY RELATED TO THE SOFTWARE,
EVEN IF THE AUTHORS HAVE BEEN ADVISED ON THE POSSIBILITY OF SUCH DAMAGE OR
IF SUCH DAMAGE COULD HAVE BEEN REASONABLY FORESEEN, AND NOTWITHSTANDING
ANY FAILURE OF ESSENTIAL PURPOSE OF ANY EXCLUSIVE REMEDY PROVIDED. SUCH LIMITATION ON DAMAGES INCLUDES, BUT IS NOT LIMITED TO, DAMAGES FOR LOSS OF GOODWILL, LOST PROFITS, LOSS OF DATA OR SOFTWARE, WORK STOPPAGE, COMPUTER FAILURE
OR MALFUNCTION OR IMPAIRMENT OF OTHER GOODS. IN NO EVENT WILL THE AUTHORS
BE LIABLE FOR THE COSTS OF PROCUREMENT OF SUBSTITUTE SOFTWARE OR SERVICES.
YOU ACKNOWLEDGE THAT THIS SOFTWARE IS NOT DESIGNED FOR USE IN ON-LINE EQUIP-

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MENT IN HAZARDOUS ENVIRONMENTS SUCH AS OPERATION OF NUCLEAR FACILITIES, AIRCRAFT NAVIGATION OR CONTROL, OR LIFE-CRITICAL APPLICATIONS. THE AUTHORS EXPRESSLY DISCLAIM ANY LIABILITY RESULTING FROM USE OF THE SOFTWARE IN ANY SUCH
ON-LINE EQUIPMENT IN HAZARDOUS ENVIRONMENTS AND ACCEPTS NO LIABILITY IN RESPECT OF ANY ACTIONS OR CLAIMS BASED ON THE USE OF THE SOFTWARE IN ANY SUCH
ON-LINE EQUIPMENT IN HAZARDOUS ENVIRONMENTS BY YOU. FOR PURPOSES OF THIS
PARAGRAPH, THE TERM “LIFE-CRITICAL APPLICATION” MEANS AN APPLICATION IN WHICH
THE FUNCTIONING OR MALFUNCTIONING OF THE SOFTWARE MAY RESULT DIRECTLY OR
INDIRECTLY IN PHYSICAL INJURY OR LOSS OF HUMAN LIFE. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. NO USE OF ANY COVERED
CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER THIS DISCLAIMER.
8 TERMINATION.
8.1.
This License and the rights granted hereunder will terminate automatically if You fail to comply with terms herein and fail to cure such breach within 30 days of becoming aware of the breach.
All sublicenses to the Covered Code which are properly granted shall survive any termination of this License. Provisions which, by their nature, must remain in effect beyond the termination of this License shall survive.
8.2.
8.3.
If You assert a patent infringement claim against Participant alleging that such Participant’s
Contributor Version directly or indirectly infringes any patent where such claim is resolved (such as by license or settlement) prior to the initiation of patent infringement litigation, then the reasonable value of the licenses granted by such Participant under Sections 2.1 or 2.2 shall be taken into account in determining the amount or value of any payment or license.
8.4. In the event of termination under Sections 8.1 or 8.2 above, all end user license agreements (excluding distributors and resellers) which have been validly granted by You or any distributor hereunder prior to termination shall survive termination.
9 LIMITATION OF LIABILITY.
UNDER NO CIRCUMSTANCES AND UNDER NO LEGAL THEORY, WHETHER TORT (INCLUDING NEGLIGENCE), CONTRACT, OR OTHERWISE, SHALL YOU, THE INITIAL DEVELOPER, ANY
OTHER CONTRIBUTOR, OR ANY DISTRIBUTOR OF COVERED CODE, OR ANY SUPPLIER OF
ANY OF SUCH PARTIES, BE LIABLE TO ANY PERSON FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OF ANY CHARACTER INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF GOODWILL, WORK STOPPAGE, COMPUTER FAILURE OR MALFUNCTION, OR ANY AND ALL OTHER COMMERCIAL DAMAGES OR LOSSES, EVEN IF SUCH
PARTY SHALL HAVE BEEN INFORMED OF THE POSSIBILITY OF SUCH DAMAGES. THIS LIMITATION OF LIABILITY SHALL NOT APPLY TO LIABILITY FOR DEATH OR PERSONAL INJURY RESULTING FROM SUCH PARTY’S NEGLIGENCE TO THE EXTENT APPLICABLE LAW PROHIBITS
SUCH LIMITATION. SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OR LIMITATION
OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THIS EXCLUSION AND LIMITATION MAY
NOT APPLY TO YOU.
10 U.S. GOVERNMENT END USERS.
11 MISCELLANEOUS.
12 RESPONSIBILITY FOR CLAIMS.
As between Initial Developer and the Contributors, each party is responsible for claims and damages arising, directly or indirectly, out of its utilization of rights under this License and You agree to work with Initial Developer and Contributors to distribute such responsibility on an equitable basis. Nothing herein is intended or shall be deemed to constitute any admission of liability. EXHIBIT A.
“The contents of this ﬁle are subject to the gSOAP Public License Version 1.3 (the “License”); you may not use this ﬁle except in compliance with the License. You may obtain a copy of

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16 Third-party materials and licenses the License at http://www.cs.fsu.edu/~engelen/soaplicense.html. Software distributed under the License is distributed on an “AS IS” basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the speciﬁc language governing rights and limitations under the License.
The Original Code of the gSOAP Software is: stdsoap.h, stdsoap2.h, stdsoap.c, stdsoap2.c, stdsoap.cpp, stdsoap2.cpp, soapcpp2.h, soapcpp2.c, soapcpp2_lex.l, soapcpp2_yacc.y, error2.h, error2.c, symbol2.c, init2.c, soapdoc2.html, and soapdoc2.pdf, httpget.h, httpget.c, stl.h, stldeque.h, stllist.h, stlvector.h, stlset.h.
The Initial Developer of the Original Code is Robert A. van Engelen. Portions created by
Robert A. van Engelen are Copyright (C) 2001-2004 Robert A. van Engelen, Genivia inc. All
Rights Reserved.
Contributor(s): “________________________.“ [Note: The text of this Exhibit A may differ slightly form the text of the notices in the Source Code ﬁles of the Original code. You should use the text of this Exhibit A rather than the text found in the Original Code Source Code for Your
Modiﬁcations.]
EXHIBIT B.
“Part of the software embedded in this product is gSOAP software. Portions created by gSOAP are Copyright (C) 2001-2004 Robert A. van Engelen, Genivia inc. All Rights Reserved. THE
SOFTWARE IN THIS PRODUCT WAS IN PART PROVIDED BY GENIVIA INC AND ANY EXPRESS
OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.“

16.2.15 Chromium licenses
16.2.15.1 Main license
Copyright (c) 2002, Stanford University All rights reserved.
Some portions of Chromium are copyrighted by individiual organizations. Please see the ﬁles
COPYRIGHT.LLNL and COPYRIGHT.REDHAT for more information.
Redistribution and use in source and binary forms, with or without modiﬁcation, are permitted provided that the following conditions are met:
• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
• Neither the name of Stanford University nor the names of its contributors may be used to endorse or promote products derived from this software without speciﬁc prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS
IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
16.2.15.2 COPYRIGHT.LLNL ﬁle
This Chromium distribution contains information and code which is covered under the following notice: Copyright (c) 2002, The Regents of the University of California. Produced at the Lawrence
Livermore National Laboratory For details, contact: Randall Frank (rjfrank@llnl.gov). UCRLCODE-2002-058 All rights reserved.
This ﬁle is part of Chromium. For details, see accompanying documentation.
Redistribution and use in source and binary forms, with or without modiﬁcation, are permitted provided that the following conditions are met:
Redistributions of source code must retain the above copyright notice, this list of conditions and the disclaimer below.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the disclaimer (as noted below) in the documentation and/or other materials provided with the distribution.
Neither the name of the UC/LLNL nor the names of its contributors may be used to endorse or promote products derived from this software without speciﬁc prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS
IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OF THE UNIVERSITY OF CALIFORNIA, THE U.S. DEPARTMENT OF ENERGY OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Additional BSD Notice
1. This notice is required to be provided under our contract with the U.S. Department of
Energy (DOE). This work was produced at the University of California, Lawrence Livermore
National Laboratory under Contract No. W-7405-ENG-48 with the DOE.
2. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately-owned rights.
3. Also, reference herein to any speciﬁc commercial products, process, or services by trade name, trademark, manufacturer or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or the University of
California. The views and opinions of authors expressed herein do not necessarily state or reﬂect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes.
16.2.15.3 COPYRIGHT.REDHAT ﬁle
This Chromium distribution contains information and code which is covered under the following notice: Copyright 2001,2002 Red Hat Inc., Durham, North Carolina.

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All Rights Reserved.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation ﬁles (the “Software”), to deal in the Software without restriction, including without limitation on the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice (including the next paragraph) shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL RED
HAT AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

16.2.16 curl license
COPYRIGHT AND PERMISSION NOTICE
Copyright (c) 1996 - 2009, Daniel Stenberg, daniel@haxx.se.
All rights reserved.
Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN
NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
OR OTHER DEALINGS IN THE SOFTWARE.
Except as contained in this notice, the name of a copyright holder shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization of the copyright holder.

16.2.17 libgd license
Portions copyright 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002 by Cold Spring
Harbor Laboratory. Funded under Grant P41-RR02188 by the National Institutes of Health.
Portions copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002 by Boutell.Com, Inc.
Portions relating to GD2 format copyright 1999, 2000, 2001, 2002 Philip Warner.
Portions relating to PNG copyright 1999, 2000, 2001, 2002 Greg Roelofs.
Portions relating to gdttf.c copyright 1999, 2000, 2001, 2002 John Ellson (ellson@lucent.com).
Portions relating to gdft.c copyright 2001, 2002 John Ellson (ellson@lucent.com).
Portions copyright 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Pierre-Alain Joye
(pierre@libgd.org).
Portions relating to JPEG and to color quantization copyright 2000, 2001, 2002, Doug Becker and copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, Thomas G. Lane. This software is based in part on the work of the Independent JPEG Group. See the ﬁle READMEJPEG.TXT for more information.
Portions relating to WBMP copyright 2000, 2001, 2002 Maurice Szmurlo and Johan Van den
Brande.

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Permission has been granted to copy, distribute and modify gd in any context without fee, including a commercial application, provided that this notice is present in user-accessible supporting documentation.
This does not affect your ownership of the derived work itself, and the intent is to assure proper credit for the authors of gd, not to interfere with your productive use of gd. If you have questions, ask. “Derived works” includes all programs that utilize the library. Credit must be given in user-accessible documentation.
This software is provided “AS IS.“ The copyright holders disclaim all warranties, either express or implied, including but not limited to implied warranties of merchantability and ﬁtness for a particular purpose, with respect to this code and accompanying documentation.
Although their code does not appear in gd, the authors wish to thank David Koblas, David
Rowley, and Hutchison Avenue Software Corporation for their prior contributions.

16.2.18 BSD license from Intel
All rights reserved.
Redistribution and use in source and binary forms, with or without modiﬁcation, are permitted provided that the following conditions are met:
• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
• Neither the name of the Intel Corporation nor the names of its contributors may be used to endorse or promote products derived from this software without speciﬁc prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS
IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

16.2.19 libjpeg License
The authors make NO WARRANTY or representation, either express or implied, with respect to this software, its quality, accuracy, merchantability, or ﬁtness for a particular purpose. This software is provided “AS IS”, and you, its user, assume the entire risk as to its quality and accuracy.
This software is copyright (C) 1991-2010, Thomas G. Lane, Guido Vollbeding. All Rights
Reserved except as speciﬁed below.
Permission is hereby granted to use, copy, modify, and distribute this software (or portions thereof) for any purpose, without fee, subject to these conditions:
(1) If any part of the source code for this software is distributed, then this README ﬁle must be included, with this copyright and no-warranty notice unaltered; and any additions, deletions, or changes to the original ﬁles must be clearly indicated in accompanying documentation.
(2) If only executable code is distributed, then the accompanying documentation must state that “this software is based in part on the work of the Independent JPEG Group”.

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(3) Permission for use of this software is granted only if the user accepts full responsibility for any undesirable consequences; the authors accept NO LIABILITY for damages of any kind.
These conditions apply to any software derived from or based on the IJG code, not just to the unmodiﬁed library. If you use our work, you ought to acknowledge us.
Permission is NOT granted for the use of any IJG author’s name or company name in advertising or publicity relating to this software or products derived from it. This software may be referred to only as “the Independent JPEG Group’s software”.
We speciﬁcally permit and encourage the use of this software as the basis of commercial products, provided that all warranty or liability claims are assumed by the product vendor. ansi2knr.c is included in this distribution by permission of L. Peter Deutsch, sole proprietor of its copyright holder, Aladdin Enterprises of Menlo Park, CA. ansi2knr.c is NOT covered by the above copyright and conditions, but instead by the usual distribution terms of the Free Software
Foundation; principally, that you must include source code if you redistribute it. (See the ﬁle ansi2knr.c for full details.) However, since ansi2knr.c is not needed as part of any program generated from the IJG code, this does not limit you more than the foregoing paragraphs do.
The Unix conﬁguration script “conﬁgure” was produced with GNU Autoconf. It is copyright by the Free Software Foundation but is freely distributable. The same holds for its supporting scripts (conﬁg.guess, conﬁg.sub, ltmain.sh). Another support script, install-sh, is copyright by X
Consortium but is also freely distributable.
The IJG distribution formerly included code to read and write GIF ﬁles. To avoid entanglement with the Unisys LZW patent, GIF reading support has been removed altogether, and the GIF writer has been simpliﬁed to produce “uncompressed GIFs”. This technique does not use the
LZW algorithm; the resulting GIF ﬁles are larger than usual, but are readable by all standard GIF decoders. We are required to state that
“The Graphics Interchange Format(c) is the Copyright property of CompuServe Incorporated.
GIF(sm) is a Service Mark property of CompuServe Incorporated.“

16.2.20 x86 SIMD extension for IJG JPEG library license
Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
Copyright 2010 D. R. Commander
Based on x86 SIMD extension for IJG JPEG library - version 1.02
Copyright (C) 1999-2006, MIYASAKA Masaru.
This software is provided ’as-is’, without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.

16.2.21 FreeBSD license
The compilation of software known as FreeBSD is distributed under the following terms:
Copyright (c) 1992-2009 The FreeBSD Project. All rights reserved.
Redistribution and use in source and binary forms, with or without modiﬁcation, are permitted provided that the following conditions are met:

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16 Third-party materials and licenses
1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS “AS IS” AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

16.2.22 NetBSD license
Copyright (c) 1992, 1993 The Regents of the University of California. All rights reserved.
This software was developed by the Computer Systems Engineering group at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and contributed to Berkeley.
Redistribution and use in source and binary forms, with or without modiﬁcation, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without speciﬁc prior written permission.
THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS “AS IS” AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

16.2.23 PCRE license
PCRE is a library of functions to support regular expressions whose syntax and semantics are as close as possible to those of the Perl 5 language.
Release 8 of PCRE is distributed under the terms of the “BSD” licence, as speciﬁed below. The documentation for PCRE, supplied in the “doc” directory, is distributed under the same terms as the software itself.

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The basic library functions are written in C and are freestanding. Also included in the distribution is a set of C++ wrapper functions, and a just-in-time compiler that can be used to optimize pattern matching. These are both optional features that can be omitted when the library is built.
THE BASIC LIBRARY FUNCTIONS. Written by: Philip Hazel; Email local part: ph10; Email domain: cam.ac.uk University of Cambridge Computing Service, Cambridge, England. Copyright
(c) 1997-2012 University of Cambridge All rights reserved.
PCRE JUST-IN-TIME COMPILATION SUPPORT. Written by: Zoltan Herczeg; Email local part: hzmester; Emain domain: freemail.hu Copyright(c) 2010-2012 Zoltan Herczeg All rights reserved.
STACK-LESS JUST-IN-TIME COMPILER. Written by: Zoltan Herczeg; Email local part: hzmester; Emain domain: freemail.hu Copyright(c) 2009-2012 Zoltan Herczeg All rights reserved.
THE C++ WRAPPER FUNCTIONS. Contributed by: Google Inc. Copyright (c) 2007-2012,
Google Inc. All rights reserved.
THE “BSD” LICENCE. Redistribution and use in source and binary forms, with or without modiﬁcation, are permitted provided that the following conditions are met:
• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
• Neither the name of the University of Cambridge nor the name of Google Inc. nor the names of their contributors may be used to endorse or promote products derived from this software without speciﬁc prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS
IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

16.2.24 libfﬁ license
Copyright (c) 1996-2012 Anthony Green, Red Hat, Inc and others. See source ﬁles for details.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation ﬁles (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

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16 Third-party materials and licenses

16.2.25 FLTK license
December 11, 2001
The FLTK library and included programs are provided under the terms of the GNU Library
General Public License (LGPL) with the following exceptions:
1. Modiﬁcations to the FLTK conﬁgure script, conﬁg header ﬁle, and makeﬁles by themselves to support a speciﬁc platform do not constitute a modiﬁed or derivative work.
The authors do request that such modiﬁcations be contributed to the FLTK project - send all contributions through the “Software Trouble Report” on the following page: http://www.ﬂtk.org/str.php 2. Widgets that are subclassed from FLTK widgets do not constitute a derivative work.
3. Static linking of applications and widgets to the FLTK library does not constitute a derivative work and does not require the author to provide source code for the application or widget, use the shared FLTK libraries, or link their applications or widgets against a usersupplied version of FLTK.
If you link the application or widget to a modiﬁed version of FLTK, then the changes to
FLTK must be provided under the terms of the LGPL in sections 1, 2, and 4.
4. You do not have to provide a copy of the FLTK license with programs that are linked to the
FLTK library, nor do you have to identify the FLTK license in your program or documentation as required by section 6 of the LGPL.
However, programs must still identify their use of FLTK. The following example statement can be included in user documentation to satisfy this requirement:
[program/widget] is based in part on the work of the FLTK project (http://www.ﬂtk.org).

16.2.26 Expat license
Copyright (c) 1998, 1999, 2000 Thai Open Source Software Center Ltd and Clark Cooper
Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006 Expat maintainers.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation ﬁles (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

16.2.27 Fontconﬁg license
Copyright (C) 2001, 2003 Keith Packard
Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting

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16 Third-party materials and licenses documentation, and that the name of the author(s) not be used in advertising or publicity pertaining to distribution of the software without speciﬁc, written prior permission. The authors make no representations about the suitability of this software for any purpose. It is provided “as is” without express or implied warranty.
THE AUTHOR(S) DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT
SHALL THE AUTHOR(S) BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

16.2.28 Freetype license
2006-Jan-27
Copyright 1996-2002, 2006 by David Turner, Robert Wilhelm, and Werner Lemberg
16.2.28.1 Introduction
The FreeType Project is distributed in several archive packages; some of them may contain, in addition to the FreeType font engine, various tools and contributions which rely on, or relate to, the FreeType Project.
This license applies to all ﬁles found in such packages, and which do not fall under their own explicit license. The license affects thus the FreeType font engine, the test programs, documentation and makeﬁles, at the very least.
This license was inspired by the BSD, Artistic, and IJG (Independent JPEG Group) licenses, which all encourage inclusion and use of free software in commercial and freeware products alike. As a consequence, its main points are that:
• We don’t promise that this software works. However, we will be interested in any kind of bug reports. (‘as is’ distribution)
• You can use this software for whatever you want, in parts or full form, without having to pay us. (‘royalty-free’ usage)
• You may not pretend that you wrote this software. If you use it, or only parts of it, in a program, you must acknowledge somewhere in your documentation that you have used the FreeType code. (‘credits’)
We speciﬁcally permit and encourage the inclusion of this software, with or without modiﬁcations, in commercial products. We disclaim all warranties covering The FreeType Project and assume no liability related to The FreeType Project.
Finally, many people asked us for a preferred form for a credit/disclaimer to use in compliance with this license. We thus encourage you to use the following text:
Portions of this software are copyright (C) <year> The FreeType Project (www.freetype.org).
All rights reserved.
Please replace <year> with the value from the FreeType version you actually use.
16.2.28.2 Legal Terms
0. Deﬁnitions Throughout this license, the terms ‘package’, ‘FreeType Project’, and ‘FreeType archive’ refer to the set of ﬁles originally distributed by the authors (David Turner, Robert Wilhelm, and Werner Lemberg) as the ‘FreeType Project’, be they named as alpha, beta or ﬁnal release. 309

16 Third-party materials and licenses
‘You’ refers to the licensee, or person using the project, where ‘using’ is a generic term including compiling the project’s source code as well as linking it to form a ‘program’ or ‘executable’. This program is referred to as ‘a program using the FreeType engine’.
This license applies to all ﬁles distributed in the original FreeType Project, including all source code, binaries and documentation, unless otherwise stated in the ﬁle in its original, unmodiﬁed form as distributed in the original archive. If you are unsure whether or not a particular ﬁle is covered by this license, you must contact us to verify this.
The FreeType Project is copyright (C) 1996-2000 by David Turner, Robert Wilhelm, and Werner
Lemberg. All rights reserved except as speciﬁed below.
1. No Warranty THE FREETYPE PROJECT IS PROVIDED ‘AS IS’ WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT WILL ANY
OF THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY DAMAGES CAUSED BY THE
USE OR THE INABILITY TO USE, OF THE FREETYPE PROJECT.
2. Redistribution This license grants a worldwide, royalty-free, perpetual and irrevocable right and license to use, execute, perform, compile, display, copy, create derivative works of, distribute and sublicense the FreeType Project (in both source and object code forms) and derivative works thereof for any purpose; and to authorize others to exercise some or all of the rights granted herein, subject to the following conditions:
• Redistribution of source code must retain this license ﬁle (‘FTL.TXT’) unaltered; any additions, deletions or changes to the original ﬁles must be clearly indicated in accompanying documentation. The copyright notices of the unaltered, original ﬁles must be preserved in all copies of source ﬁles.
• Redistribution in binary form must provide a disclaimer that states that the software is based in part of the work of the FreeType Team, in the distribution documentation. We also encourage you to put an URL to the FreeType web page in your documentation, though this isn’t mandatory.
These conditions apply to any software derived from or based on the FreeType Project, not just the unmodiﬁed ﬁles. If you use our work, you must acknowledge us. However, no fee need be paid to us.
3. Advertising Neither the FreeType authors and contributors nor you shall use the name of the other for commercial, advertising, or promotional purposes without speciﬁc prior written permission. We suggest, but do not require, that you use one or more of the following phrases to refer to this software in your documentation or advertising materials: ‘FreeType Project’, ‘FreeType
Engine’, ‘FreeType library’, or ‘FreeType Distribution’.
As you have not signed this license, you are not required to accept it. However, as the FreeType
Project is copyrighted material, only this license, or another one contracted with the authors, grants you the right to use, distribute, and modify it. Therefore, by using, distributing, or modifying the FreeType Project, you indicate that you understand and accept all the terms of this license. 4. Contacts There are two mailing lists related to FreeType:
• freetype@nongnu.org
Discusses general use and applications of FreeType, as well as future and wanted additions to the library and distribution. If you are looking for support, start in this list if you haven’t found anything to help you in the documentation.

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• freetype-devel@nongnu.org
Discusses bugs, as well as engine internals, design issues, speciﬁc licenses, porting, etc.
Our home page can be found at http://www.freetype.org 16.2.29 VPX License
Copyright (c) 2010, The WebM Project authors. All rights reserved.
Redistribution and use in source and binary forms, with or without modiﬁcation, are permitted provided that the following conditions are met:
• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
• Neither the name of Google, nor the WebM Project, nor the names of its contributors may be used to endorse or promote products derived from this software without speciﬁc prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS
IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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17 VirtualBox privacy information
Version 5, Dec 13, 2012
The Oracle Privacy Policies posted on http://www.oracle.com/html/privacy.html apply to your personal data collected and used by Oracle. The following privacy information describes in more detail which information is exchanged between the VirtualBox application and Oracle, and which information is collected by the virtualbox.org website.
§ 1 virtualbox.org. The “virtualbox.org” website logs anonymous usage information such as your IP address, geographical location, browser type, referral source, length of visit and number of page views while you visit (collectively, “anonymous data”). In addition, but only if you choose to register, the website’s bug tracking and forum services store the data you choose to reveal upon registration, such as your user name and contact information.
§ 2 Cookies. The virtualbox.org website, the bug tracker and the forum services use cookies to identify and track the visiting web browser and, if you have registered, to facilitate login. Most browsers allow you to refuse to accept cookies. While you can still visit the website with cookies disabled, logging into the bug tracker and forum services will most likely not work without them.
§ 3 VirtualBox registration process. The VirtualBox application may ask that the user optionally register with Oracle. If you choose to register, your name, e-mail address, country and company will be submitted to Oracle and stored together with the IP address of the submitter as well as product version and platform being used.
§ 4 Update notiﬁcations. The VirtualBox application may contact Oracle to ﬁnd out whether a new version of VirtualBox has been released and notify the user if that is the case. In the process, anonymous data such as your IP address and a non-identifying counter, together with the product version and the platform being used, is sent so that the server can ﬁnd out whether an update is available. By default, this check is performed once a day. You change this interval or disable these checks altogether in the VirtualBox preferences.
§ 5 Usage of personal information. Oracle may use anonymous and personal data collected by the means above for statistical purposes as well as to automatically inform you about new notices related to your posts on the bug tracker and forum services, to administer the website and to contact you due to technical issues. Oracle may also inform you about new product releases related to VirtualBox.
In no event will personal data without your express consent be provided to any third parties, unless Oracle may be required to do so by law or in connection with legal proceedings.
§ 6 Updates. Oracle may update the privacy policy at any time by posting a new version at http://www.oracle.com/html/privacy.html and the privacy information will be kept up to date in the documentation which comes with the VirtualBox application. You should check these places occasionally to ensure you are happy with any changes.

312

Glossary
A
ACPI Advanced Conﬁguration and Power Interface, an industry speciﬁcation for BIOS and hardware extensions to conﬁgure PC hardware and perform power management. Windows
2000 and higher as well as Linux 2.4 and higher support ACPI. Windows can only enable or disable ACPI support at installation time.
AHCI Advanced Host Controller Interface, the interface that supports SATA devices such as hard disks. See chapter 5.1, Hard disk controllers: IDE, SATA (AHCI), SCSI, SAS, USB MSC, page
81.
AMD-V The hardware virtualization features built into modern AMD processors. See chapter
10.3, Hardware vs. software virtualization, page 219.
API Application Programming Interface.
APIC Advanced Programmable Interrupt Controller, a newer version of the original PC PIC
(programmable interrupt controller). Most modern CPUs contain an on-chip APIC (“local APIC”). Many systems also contain an I/O APIC (input output APIC) as a separate chip which provides more than 16 IRQs. Windows 2000 and higher use a different kernel if they detect an I/O APIC during installation. Therefore an I/O APIC must not be removed after installation.
ATA Advanced Technology Attachment, an industry standard for hard disk interfaces (synonymous with IDE). See chapter 5.1, Hard disk controllers: IDE, SATA (AHCI), SCSI, SAS, USB
MSC, page 81.

B
BIOS Basic Input/Output System, the ﬁrmware built into most personal computers which is responsible of initializing the hardware after the computer has been turned on and then booting an operating system. VirtualBox ships with its own virtual BIOS that runs when a virtual machine is started.

C
COM Microsoft Component Object Model, a programming infrastructure for modular software.
COM allows applications to provide application programming interfaces which can be accessed from various other programming languages and applications. VirtualBox makes use of COM both internally and externally to provide a comprehensive API to 3rd party developers. 313

Glossary

D
DHCP Dynamic Host Conﬁguration Protocol. This allows a networking device in a network to acquire its IP address (and other networking details) automatically, in order to avoid having to conﬁgure all devices in a network with ﬁxed IP addresses. VirtualBox has a built-in DHCP server that delivers an IP addresses to a virtual machine when networking is conﬁgured to NAT; see chapter 6, Virtual networking, page 94.
DKMS Dynamic Kernel Module Support. A framework that simpliﬁes installing and updating external kernel modules on Linux machines; see chapter 2.3.2, The VirtualBox kernel module, page 36.

E
EFI Extensible Firmware Interface, a ﬁrmware built into computers which is designed to replace the aging BIOS. Originally designed by Intel, most modern operating systems can now boot on computers which have EFI instead of a BIOS built into them; see chapter 3.12,
Alternative ﬁrmware (EFI), page 57.
EHCI Enhanced Host Controller Interface, the interface that implements the USB 2.0 standard.

G
GUI Graphical User Interface. Commonly used as an antonym to a “command line interface”, in the context of VirtualBox, we sometimes refer to the main graphical VirtualBox program as the “GUI”, to differentiate it from the VBoxManage interface.
GUID See UUID.

I
IDE Integrated Drive Electronics, an industry standard for hard disk interfaces. See chapter 5.1,
Hard disk controllers: IDE, SATA (AHCI), SCSI, SAS, USB MSC, page 81.
I/O APIC See APIC. iSCSI Internet SCSI; see chapter 5.10, iSCSI servers, page 92.

M
MAC Media Access Control, a part of an Ethernet network card. A MAC address is a 6-byte number which identiﬁes a network card. It is typically written in hexadecimal notation where the bytes are separated by colons, such as 00:17:3A:5E:CB:08.
MSI Message Signaled Interrupts, as supported by modern chipsets such as the ICH9; see chapter
3.4.1, “Motherboard” tab, page 47. As opposed to traditional pin-based interrupts, with
MSI, a small amount of data can accompany the actual interrupt message. This reduces the amount of hardware pins required, allows for more interrupts and better performance.

314

Glossary

N
NAT Network Address Translation. A technique to share networking interfaces by which an interface modiﬁes the source and/or target IP addresses of network packets according to speciﬁc rules. Commonly employed by routers and ﬁrewalls to shield an internal network from the Internet, VirtualBox can use NAT to easily share a host’s physical networking hardware with its virtual machines. See chapter 6.3, Network Address Translation (NAT), page 96.

O
OVF Open Virtualization Format, a cross-platform industry standard to exchange virtual appliances between virtualization products; see chapter 1.14, Importing and exporting virtual machines, page 30.

P
PAE Physical Address Extension. This allows accessing more than 4 GB of RAM even in 32-bit environments; see chapter 3.3.2, “Advanced” tab, page 46.
PIC See APIC.
PXE Preboot Execution Environment, an industry standard for booting PC systems from remote network locations. It includes DHCP for IP conﬁguration and TFTP for ﬁle transfer. Using
UNDI, a hardware independent driver stack for accessing the network card from bootstrap code is available.

R
RDP Remote Desktop Protocol, a protocol developed by Microsoft as an extension to the ITU
T.128 and T.124 video conferencing protocol. With RDP, a PC system can be controlled from a remote location using a network connection over which data is transferred in both directions. Typically graphics updates and audio are sent from the remote machine and keyboard and mouse input events are sent from the client. A VirtualBox extension package by Oracle provides VRDP, an enhanced implementation of the relevant standards which is largely compatible with Microsoft’s RDP implementation. See chapter 7.1, Remote display
(VRDP support), page 105 for details.

S
SAS Serial Attached SCSI, an industry standard for hard disk interfaces. See chapter 5.1, Hard disk controllers: IDE, SATA (AHCI), SCSI, SAS, USB MSC, page 81.
SATA Serial ATA, an industry standard for hard disk interfaces. See chapter 5.1, Hard disk controllers: IDE, SATA (AHCI), SCSI, SAS, USB MSC, page 81.
SCSI Small Computer System Interface. An industry standard for data transfer between devices, especially for storage. See chapter 5.1, Hard disk controllers: IDE, SATA (AHCI), SCSI, SAS,
USB MSC, page 81.

315

Glossary
SMP Symmetrical Multiprocessing, meaning that the resources of a computer are shared between several processors. These can either be several processor chips or, as is more common with modern hardware, multiple CPU cores in one processor.
SSD Solid-state drive, uses microchips for storing data in a computer system. Compared to classical hard-disks they are having no mechanical components like spinning disks.

T
TAR A widely used ﬁle format for archiving. Originally, this stood for “Tape ARchive” and was already supported by very early Unix versions for backing up data on tape. The ﬁle format is still widely used today, for example, with OVF archives (with an .ova ﬁle extension); see chapter 1.14, Importing and exporting virtual machines, page 30.

U
UUID A Universally Unique Identiﬁer – often also called GUID (Globally Unique Identiﬁer) – is a string of numbers and letters which can be computed dynamically and is guaranteed to be unique. Generally, it is used as a global handle to identify entities. VirtualBox makes use of UUIDs to identify VMs, Virtual Disk Images (VDI ﬁles) and other entities.

V
VM Virtual Machine – a virtual computer that VirtualBox allows you to run on top of your actual hardware. See chapter 1.2, Some terminology, page 11 for details.
VMM Virtual Machine Manager – the component of VirtualBox that controls VM execution. See chapter 10.2, VirtualBox executables and components, page 217 for a list of VirtualBox components.
VRDE VirtualBox Remote Desktop Extension. This interface is built into VirtualBox to allow
VirtualBox extension packages to supply remote access to virtual machines. A VirtualBox extension package by Oracle provides VRDP support; see chapter 7.1, Remote display (VRDP support), page 105 for details.
VRDP See RDP.
VT-x The hardware virtualization features built into modern Intel processors. See chapter 10.3,
Hardware vs. software virtualization, page 219.

X xHCI eXtended Host Controller Interface, the interface that implements the USB 3.0 standard.
XML The eXtensible Markup Language, a metastandard for all kinds of textual information. XML only speciﬁes how data in the document is organized generally and does not prescribe how to semantically organize content.
XPCOM Mozilla Cross Platform Component Object Model, a programming infrastructure developed by the Mozilla browser project which is similar to Microsoft COM and allows applications to provide a modular programming interface. VirtualBox makes use of XPCOM on
Linux both internally and externally to provide a comprehensive API to third-party developers.

316

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