...In this lab, we analyzed the packets exchanged using the DHCP protocol in Wireshark. To understand this, first we must know what DHCP is. WHAT IS DHCP? DHCP is short for Dynamic Host Configuration Protocol. It is a network protocol in the IP suite that is used to provide IP address and other related configuration information like subnet masks and default gateway to all the hosts in an organization. DHCP also works as a client/server protocol. In small organizations, it is possible for a network administrator to manually assign the IP addresses to hosts in the network, depending on their requirements. But in large organizations it is impossible for a network administrator to manually assign IP addresses to all the hosts in the network. It is...
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...1. e 2. h 3. f 4. a 5. d 6. b 7. g 8. i 9. c 10. j Multiple Choice 1. c When a DHCP-configured computer boots up, it will broadcast a DHCPDISCOVER packet to locate any available DHCP server in order to request DHCP IP address information. 2. c DHCP operates at the Application Layer of the OSI model. 3. a The TFTP protocol is a lightweight alternative to FTP. It is capable of this level of efficiency because it uses the connectionless User Datagram Protocol (UDP) for communication rather than the acknowledgement-based Transmission Control Protocol (TCP). 4. b T1 is a time indicator that corresponds to 50% of the DHCP lease time; T2 corresponds to 87.5% of the total DHCP lease time. 5. b A DHCP server will hand out IP addresses to requesting clients from its available address pool, which consists of the total address range less any IP addresses that have been configured as exclusions from the available range. 6. c The TFTP protocol was used by BOOTP, the predecessor to DHCP, which was used to provide automatic IP addressing information to diskless workstations. 7. c When you reconcile a server or a scope, the DHCP service uses both the summary information in the registry and the detailed information in the DHCP database to reconstruct the most current view of the DHCP service. 8. c Superscopes contain only a list of member scopes or child scopes that can be activated together; they are not used to...
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...Course Objectives and Learning Outcomes In this assignment, you will explain the function of DHCP and DNS. Assignment Requirements Write a 1-page report summarizing IT-management overhead in reference to DHCP and DNS. In your report, address IT-management overhead in reference to DNS and DHCP, with the following question in mind: 1. How many hosts does it take to justify the time and effort to setup a centrally managed solution for name resolution and address allocation? (In other words, is it worth setting up DHCP for two computers? 5? 25?) Consider both MS Windows Server DNS and DHCP as well as other, special use devices where DNS or DHCP may be built-in. 2. At what point should DNS or DHCP be considered a priority and require some level of redundancy? 3. Should servers use DHCP? Submission Requirements Maximum 1 page, Microsoft Word, double-spaced, 12 pt. font 1. How many hosts does it take to justify the time and effort to setup a centrally managed solution for name resolution and address allocation? (In other words, is it worth setting up DHCP for two computers? 5? 25?) Consider both MS Windows Server DNS and DHCP as well as other, special use devices where DNS or DHCP may be built-in. I believe one host is enough. In fact, if the host has a functioning network interface which is connected to a network chances are it is managed by DHCP uses DNS for name resolution. Although most end users don’t know or understand the how their...
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...Lab 2 worksheet CONFIGURING DNS AND DHCP THIS LAB CONTAINS THE FOLLOWING EXERCISES: Exercise 2.1 Designing a DNS Namespace Exercise 2.2 Creating a Zone Exercise 2.3 Creating Domains Exercise 2.4 Creating Resource Records Exercise 2.5 Creating a Scope Exercise 2.6 Confirming DHCP Server Functionality Exercise 2.7 Configuring DHCP Reservations Workstation Reset: Returning to Baseline Estimated lab time: 100 minutes |Exercise 2.1 |Designing a DNS Namespace | |Overview |You have been tasked with creating a test DNS namespace structure for your organization. Your first | | |task is to design that namespace by specifying appropriate domain and host names for the computers in| | |the division. | |Completion time |15 minutes | 2. In the diagram provided in Figure 2-1, write both the domain names and the fully qualified domain names that you have selected for the computers in the appropriate spaces. Figure 2-1 |Exercise 2.2 |Creating a Zone | |Overview...
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...Unit 2: DHCP Troubleshooting Dear Junior Admin, Based on the what you have told me regarding the DHCP scope the overall corporate IP address, it sounds like you have a lease time settings which is probably set to renew ip addresses at the default times. Here is your options on what you can do with DHCP: Table 4.5 Default DHCP Options Code Option name Meaning 1 Subnet mask Specifies the subnet mask of the client subnet. This option is defined in the DHCP Manager Create Scope or Scope Properties dialog box. It cannot be set directly in the DHCP Options dialog box. 3 Router Specifies a list of IP addresses for routers on the client's subnet. Multihomed computers can have only one list per computer, not one per network adapter. 6 DNS servers Specifies a list of IP addresses for DNS name servers available to the client. 15 Domain name Specifies the DNS domain name that the client should use for DNS computer name resolution. 44 WINS/NBNS servers Specifies a list of IP addresses for NetBIOS name servers (NBNS). 46 WINS/NBT node type Allows configurable NetBIOS over TCP/IP (NetBT) clients to be configured as described in RFC 1001/1002, where 1 = b-node, 2 = p-node, 4 = m-node, and 8 = h-node. On multihomed computers, the node type is assigned to the entire computer, not to individual network adapters. 47 NetBIOS scope ID 1 Specifies a text string that is the NetBIOS over TCP/IP scope ID for the client, as specified in RFC 1001/1002. 51 Lease time ...
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...fill in the bubble for the correct answer(s), any other mark such as an X or just a line through it will be marked as incorrect. 1. DHCP frees system administrators from manually configuring each host on the network. A True B False 2. The smaller the network, the greater the benefit of using a dynamic address assignment. A True B False 3. DHCP provides three key benefits to those managing and maintaining a TCP/IP network. A True B False 4. The key aspect of the DHCP process is that it is dynamic. A True B False 5. Once a DHCP scope is defined and exclusion ranges are applied, the remaining addresses form what is called an available address pool within the scope. A B True False 6. To conserve disk space, DNS servers store only the most recent updates. A True B False 7. The primary DNS server for a zone is not required to perform an incremental zone transfer. A True B False Steve Todd Page 1 of 8 8. For replication of Active Directory–integrated zones, DNS notification is needed. A True B False 9. Scavenging is enabled by default. A True B False 10. As long as the TTL for a cached resource record does not expire, a DNS server can continue to cache and use the resource record again when answering queries by its clients that match these resource records. A B True False 11. The Reverse Address Resolution Protocol (RARP) was designed for what reason? A B C D to discover the Media Access Control (MAC) address (an address unique to a Network Interface Card) that corresponds...
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...range * g. Joint Engine Technology (JET) * h. reservation * i. rogue DHCP server * j. T2 * E 1. This DHCP message type is sent by a DHCP client when it no longer requires the use of an IP address that it has leased from a DHCP server. * H 2. You can configure one of these to ensure that a DHCP client always receives the same IP address from a particular DHCP server. * F 3. This is used to ensure that a particular address or block of addresses within a scope is not assigned to DHCP clients by a DHCP server. * A 4. You must do this to any DHCP server that needs to function within an Active Directory domain. * D 5. A DHCP client will send this message type if it determines that an IP address offered by a DHCP server is already in use. * B 6. This is performed by a DHCP server when corruption is detected within the DHCP database. * G 7. The DHCP database is based on this database technology. * I 8. Authorizing DHCP servers in Active Directory is designed to prevent against these. * C 9. These provide DHCP parameters to DHCP clients based on vendor or user type. * J 10. This defaults to 87.5% of the total DHCP lease. Multiple Choice Select all answers that apply for the following questions. 1. Which of the following DHCP message types is sent first in the process of obtaining an address lease? ...
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...DHCP Troubleshooting Dear IT Admin: I am working at a branch office and have been tasked with changing out the DHCP scope to match the overall corporate IP address scheme. The main office assigned me an IP address range of 192.168.0.200 through 192.168.0.225. I changed the scope on Friday afternoon and came in on Monday morning to discover that only some of the workstations had picked up new leases from the new DHCP scope. Any ideas as to what may be happening what I might check or adjust? Thank you, Junior Admin From IT Admin: To: Junior Admin: A scope must be defined and activated before DHCP clients can use the DHCP server for dynamic TCP/IP configuration. DHCP servers do not communicate scope information with each other, you must be careful to define scopes so that multiple DHCP servers are not assigning the same IP address to multiple clients or assigning addresses that are statically assigned to existing IP hosts. A DHCP server can only service requests for a scope that has a network ID that is the same as the network ID of its IP address. Use the display dhcp server tree all command to verify that an address pool containing or residing on the same subnet as the subnet of the receiving interface’s IP address is configured. The DHCP server assigns IP addresses with leases (support for lease duration depends on the device model). If an IP address has passed its lease duration, the DHCP server does not assign the IP address. Execute the display dhcp server ip-in-use...
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...domain name (FQDN) to its assigned IP address(es). While DHCP provides a powerful mechanism for automatically configuring client IP addresses, until recently DHCP did not notify the DNS service to update the DNS records on the client; specifically, updating the client name to an IP address, and IP address to name mappings maintained by a DNS server. Without a way for DHCP to interact with DNS, the information maintained by DNS for a DHCP client may be incorrect. For example, a client may acquire its IP address from a DHCP server, but the DNS records would not reflect the IP address acquired nor provide a mapping from the new IP address to the computer name (FQDN). In Windows 2000, DHCP servers and clients can register with DNS to provide this update service if the DNS server supports DNS with dynamic updates. The Windows 2000 DNS service supports dynamic updates. A Windows 2000 DHCP server can register with a DNS server and update pointer and address (A) resource records on behalf of its DHCP-enabled clients using the DNS dynamic update protocol. The ability to register both A and PTR type records lets a DHCP server act as a proxy for clients using Microsoft Windows 95 and Windows NT 4.0 for the purpose of DNS registration. DHCP servers can differentiate between Windows 2000 and other clients. An additional DHCP option code (option code 81) enables the return of a client's FQDN to the DHCP server. If implemented, the DHCP server can dynamically update DNS to modify an individual...
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...Configuring and Maintaining the DHCP and DNS Server Roles Unit 2 Jovanny Avelino Client-Server II NT1330 Professor Arthur VIII Due: 3/21/2016 DHCP: DHCP is a standard protocol that make TCP/IP network configuration much easier for the administrator by dynamically assigning IP addressing and providing additional configuration information to DHCP clients automatically. DHCP configuration information can centrally manage all information can stored in one single location. Because DHCP is dynamically host configuration can eliminate the prose of manually configured all client IP address. Other benefit of DHCP is the opportunity of set up the subnet mask, default gateway and the DNS IP address. And give the flexibility of change IP address when is need it. The DHCP server have different ways to communicate with the client: * DHCPDISCOVER: is when the client send a broadcast to find a DHCP server. * DHCPOFFER: soon and he server find the client than the server respond, and send a offer. * DHCPREQUEST: is when the client respond to the offered from the DHCP server. * DHCPDECLIEN: mean that the client declined the DHCP server offered. * DHCPACK: is the way the DHCP server confirm the IP address and configuration parameters. * DHCPRELEASE: is the way the client cancel the IP address lease. * DHCPINFORM: is a message send by the client asking for additional configuration parameters, also use for detect unauthorized DHCP servers. Using those terminology...
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...you know aout DHCP and a sample configuration for DCHP. We will look at the differences and the similarities between IPv6 and IPv4. Also will be looking at how DHCP can be configured in Linux. In the next couple paragraphs, you will see these listed. IPv4 is the fourth version of Internet protocol which uses 32 bit addressing whereas IPv6 is a next generation internet protocol which uses 128 bits addressing. IPv4 allows 4,294,967,296 unique addresses whereas IPv6 can hold 340-undecillion unique IP addresses. IPv4 address notation: 239.255.255.255, 255.255.255.0. IPv6 addresses are denoted by eight groups of hexadecimal quartets separated by colons in between them. An example of a valid IPv6 address: 2001:cdba:0000:0000:0000:0000:3257:9652. (http://tianrunhe.wordpress.com/2012/04/25/compare-and-contrast-ipv4-and-ipv6/) When a DHCP client system connects to the network, dhclient requests a lease from the DHCP server and configures the client's network interface(s). Once a DHCP client has requested and established a lease, it stores information about the lease in a file nameddhclient.leases, which is stored in the /var/lib/dhclient directory. This information is used to reestablish a lease when either the server or the client needs to reboot. The DHCP client configuration file, /etc/dhclient.conf, is required only for custom configurations. The following dhclient.conf file specifies a single interface, eth0: $ cat /etc/dhclient.conf interface "eth0" { send dhcp-client-identifier...
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...DHCP: DynamicHostConfigurationProtocol In simple terms, DHCP determines if your IP is static or dynamic and the length of time an IP address is assigned. Dynamic Host Configuration Protocol is controlled by a DHCP server. Your router can be a DHCP server…and if you’re on a home network, it most likely serves this purpose. Read more: http://www.whatismyip.com/ip-faq/what-is-dhcp/#ixzz2SFrnB7wR I know this might be confusing because the word dynamic is in the term, but just because you have DHCP enabled on your computer doesn’t mean you can’t be assigned a static IP. DHCP enabled on your computer simply means you’re letting a DHCP server assign its IP. Having it enabled DOES NOT mean it’s a DHCP server. A true DHCP server (not your Linksys router) gives the LAN Admin a ton of control with IP assigning. Ever print to a network printer? Ever wonder how that printer keeps its network assignment? Each network device has a MAC address. You can assign a static IP at the server to a specific MAC address. This allows the network printer to always get the same IP even after it reboots and without assigning the IP at the printer. If you print the network configuration at the printer, it will probably tell you that DHCP is enabled and no static IP is assigned. That’s because the IP assignment is handled at the server. Your ISP has a DHCP server. They can assign IPs by modem MAC addresses. When your modem comes online, it communicates to the network indicating it is looking for...
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...IT-management overhead in reference to DNS and DHCP In order to address the issue of when is it cost effective to employ the use of DHCP for a computer network we first have to get a brief understanding of the terms DNS and DHCP. Domain Name Servers (DNS) for short is like a phone directory for the internet. They translate domain names into IP (Internet Protocol) addresses. Domain names are easier for people to remember, computers access the internet based on IP addresses. Dynamic Host Configuration Protocol (DHCP) is a network protocol that allows a server to automatically assign an IP address to a computer. Now that we have defined these two terms it is possible to analyze the cost effectiveness of a DHCP server. To manually configure a computer workstation with an IP address is not difficult. On the other hand to manually configure tens, hundreds, or thousands of workstations would be too time consuming, it also increases the chance of duplicating IP addresses, misconfiguring the subnet mask or other network protocols. It is in these instances that DHCP is not only a handy tool it is a needed tool for network administrators to perform their job. There are three main instances to manually assign addresses. 1) When there are no configured DHCP servers on the network and the network has multiple network segments. 2) When you are configuring a computer as a DHCP server, you assign that computer a static IP address. 3) When you configure computers as important network...
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...and configurations of the DHCP Server Role for Windows Server 2008. In order to fully understand how DHCP Server Roles operate within the network, you first have to know why, when, and where the DHCP Server Role will be used. What is a server role? A set of software programs that when installed and configured properly, allows a computer to perform specialized functions for numerous clients or other computers within a network. They describe the main function, or use of a computer. A certain computer can be created to perform a clear-cut function that’s greatly used in an enterprise, or perform many roles if it’s not used too much. They provide aid to client’s throughout an organization, that’s directed by other computers, like websites, printers, or files....
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...As far as the issue at hand there might be an issue with some of the hosts not being authorized through DHCP in the active directory. You can do this by going into the device and going to the console tree, click DHCP; on the Action menu, click Manage authorized servers (the Manage Authorized Servers dialog box appears); Click Authorize; when prompted, type the name or IP address of the DHCP server to be authorized, and then click OK. This can be done on the devices that are not receiving the new address and DHCP will automatically configure the rest. In the command line, type in ipconfig / all to allocate if the devices that are not working have any IP address at all and see if DHCP is enabled. This will tell you if the device is using DHCP. Since the DHCP server was changed, a DHCP server can only service requests for a scope that has a network ID that is the same as the network ID of its IP address. You have to make sure that the DHCP server IP address falls in the same network range as the scope it is servicing. For example your IP address range is 192.168.0.200 through 192.168.0.225, a server with an IP address in the 192.168.0.0 network cannot assign addresses from scope 10.0.0.0. Using ipconfig in the command line will tell what IP address is being used. If it is not the same on the devices that are working then that is where the problem is. Also, the computers not working could use a simple re-boot and maybe the addresses will be automatically assigned or going...
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