...IP ADDRESSING: An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there." The designers of the Internet Protocol defined an IP address as a 32-bit number[ and this system, known as Internet Protocol Version 4 (IPv4), is still in use today. However, due to the enormous growth of the Internet and the predicted depletion of available addresses, a new addressing system (IPv6), using 128 bits for the address, was developed in 1995, standardized as RFC 2460 in 1998, and its deployment has been ongoing since the mid-2000s. In the most widely installed level of the Internet Protocol (IP) today, an IP address is a 32-bit number that identifies each sender or receiver of information that is sent in packets across the Internet. When you request an HTML page or send e-mail, the Internet Protocol part of TCP/IP includes your IP address in the message (actually, in each of the packets if more than one is required) and sends it to the IP address that is obtained by looking up the domain name in the Uniform Resource Locator you requested or in the e-mail address you're sending a note to. At the other...
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...Configuring Network Address Translation: Getting Started Document ID: 13772 Contents Introduction Prerequisites Requirements Components Used Conventions Quick Start Steps for Configuring and Deploying NAT Defining NAT Inside and Outside Interfaces Example: Allowing Internal Users to Access the Internet Configuring NAT to Allow Internal Users to Access the Internet Configuring NAT to Allow Internal Users to Access the Internet Using Overloading Example: Allowing the Internet to Access Internal Devices Configuring NAT to Allow the Internet to Access Internal Devices Example: Redirecting TCP Traffic to Another TCP Port or Address Configuring NAT to Redirect TCP Traffic to Another TCP Port or Address Example: Using NAT During a Network Transition Configuring NAT for Use During a Network Transition Example: Using NAT in Overlapping Networks Difference between One−to−One Mapping and Many−to−Many Verifying NAT Operation Conclusion Related Information Introduction This document explains configuring Network Address Translation (NAT) on a Cisco router for use in common network scenarios. The target audience of this document is first time NAT users. Note: In this document, when the internet, or an internet device is referred to, it means a device on any external network. Prerequisites Requirements This document requires a basic knowledge of the terms used in connection with NAT. Some of the definitions can be found in NAT: Local and Global Definitions. Components Used The information in this...
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...Difference between static and dynamic IPs. When a device is assigned a static IP address, it does not change. The device always has the same IP address. Most devices use dynamic IP addresses, which are assigned by the network when they connect. About static IPs for small business Static IP addresses An Internet Protocol (IP) address is a unique number assigned to each computer on a network. An IP address identifies computers on the Internet. A computer on the Internet can have a static IP address, which means it stays the same over time, or a dynamic IP address, which means the address can change over time. When you might need static IPs You might need static IPs if one or more of these scenarios applies to you: • Maintain your own web server or other Internet server, such as an email server, that requires users to connect from the Internet. • Have external devices or services that must connect to your network via IP address (for example, 74.125.224.72) rather than by name (for example, google.com). • Use a VPN or other service to remotely connect to computers in your business. Well, the first thing I would ask you is what Class of address does 172 fall under? This is vital. (This would be a Class B address because their range is 128-191) Therefore, be definition, the network mask is 255.255.0.0, or /16... Now, with a given IP and mask of 172.25.102.41 /22 you can see that they are using 6 bits for subnetting. (/16 default, and now using /22). This is a mask of...
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...IP Addresses Classes and Special-Use IP Address Space The history behind IP address classes can be dated back to September of 1981. With the standardization of IP, each system connected to an IP-based internet required a unique 32-bit internet address value. The first part of the address identifies the network that the host is present in, while the second part identifies that particular host. While more and more host machines are established on a particular network comes the need to properly identify each of them. All host connected to a network share the same network number (which is the first part of the address value) but must have a unique host number (second part). The only way hosts can share the same host number is if they are on 2 different networks. As years past more and more networks were established throughout the entire world. To handle the flexibility of growing networks, internet designers decided that IP address space should be divided into three address classes: Class A, Class B, and Class C. These three classes are the more publicly available classes and are the most well known. There are also two more classes that are not publicly available: classes D and E. These 2 classes are more for experimental purpose and are not issued publicly. Classes are determined by the first few binary bits of a IP address. These bits known as high-order bits are read by IP software to determine the logical network and host addresses for a device. Each class designates what...
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...User Guide YML864 Rev1 www.netcomm.com.a� ����4 ��e�� ����e 54Mbps Wireless Router 1 NB504 CoNteNts Package Contents .........................................................................................................................................4 Chapter 1: About this Guide ..........................................................................................................................5 1.1 Purposes ...........................................................................................................................................5 1.2 Conventions .......................................................................................................................................5 1.3 Overview of this User Guide ................................................................................................................5 Chapter 2: Introduction .................................................................................................................................6 2.1 Overview of the Router........................................................................................................................6 2.2 Features ............................................................................................................................................7 2.3 Panel Layout ......................................................................................................................................8 2.3.1 The Front...
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...____________________________ Build the OSI Model by providing the following information: Layer # | Layer Name | Function | | | | | | | | | | | | | | | | | | | | | | Internet Protocol The Internet Protocol (IP) is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. IP has the task of delivering packets from the source host to the destination host solely based on the IP addresses contained in the packet. IP defines packet structures that encapsulate the data to be delivered and defines the addressing used to identify the source and destination information. IP is a service in the connection-oriented Transmission Control Protocol (TCP) – thus it is often referred to as the TCP/IP Suite. Two versions of IP: IP Version | Number Format | # of Bits | Example | | | | | | | | | Subnets/Subnetting Subnetting is the practice of dividing a large network into two or more smaller networks (subnets) – this is typically done to improve manageability and performance. Subnet Methods | | | | | Classful: Classful subnetting is a method for allocating IP addresses using five classes of...
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...1. What is a byte? 8 bits 2. When using a truth table, 1 and 0 equal __False____. 3. What do parentheses do in mathematical equations? Indicate what operations do to first 4. What is a node on a network? Hardware connected to the network 5. Which physical topology has the inherent weakness of a single point of failure? Star 6. In a Web address, which part identifies the protocol being used? HTTP 7. What is basic to every networking standard? (Hint: relates to Documentation) Beyond the ideas in a standard, people must agree to a particular version of document 8. Why is the TCP/IP model divided into layers? The layers make TCP/IP easier for humans to understand what TCP/IP does. It also makes it easier to divide the work among different products. * - write protocols, - create standards, - how networks work 9. Which layer of the OSI model is responsible for encryption and compression? Presentation Layer 10. What does the following graphic illustrate? Simple Direct Current being used 11. What is a network encoding scheme? In networking, the encoding scheme defines the electrical equivalent: the electricity that means a 1 or a 0. *Interpreted between nodes 12. What causes full duplex to transmit and receive simultaneously? With full duplex, both endpoints can send at the same time, enabled because the endpoints use multiple wire pairs. Using multiple pairs allows multiple electrical circuits, so the encoders/decoders do not get confused. *for wires ...
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...lookup: a. Routing Table Format- A routing table is used by TCP/IP network routers to calculate the destinations of messages it is responsible for forwarding. The table is a small in-memory database managed by the router's built-in hardware and software. Each IP address identifies a remote router (or other network gateway) that the local router is configured to recognize. For each IP address, the routing table additionally stores a network mask and other data that specifies the destination IP address ranges that remote device will accept. Home network routers utilize a very small routing table because they simply forward all outbound traffic to the Internet Service Provider (ISP) gateway which takes care of all other routing steps. Home router tables typically contain ten or fewer entries. By comparison, the largest routers at the core of the Internet backbone must maintain the full Internet routing table that exceeds 100,000 entries and growing as the Internet expands. b. Routing Lookup Mechanism- c. Classful vs. Classless Routing- Classful Routing, which is sometimes called a classful network. If you are using a classful routing protocol then all of your networks are in different classes and are separated by a router. Remember that the useable IPv4 address ranges are divided into classes. Class A 1-126, Class B 128-191, and Class C 192-223. So when we talk about a classful routing protocol, it will only look at the IP address class and not the subnet mask. This is the problem;...
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...12/7/2014 IP Spoofing Cisco Systems The Internet Protocol Journal, Volume 10, No. 4 IP Spoofing HOME ABOUT CISCO PUBLICATIONS AND MERCHANDISE THE INTERNET PROTOCOL JOURNAL ISSUES VOLUME 10, NUMBER 4, DECEMBER 2007 Book Review Call for Papers Download PDF Fragments From the Editor IP Spoofing Looking Toward the Future Remembering Itojun Security Standards Layers above IP use the source address in an incoming packet to identify the sender. To communicate with the sender, the receiving station sends a reply by using the source address in the datagram. Because IP makes no effort to validate whether the source address in the packet generated by a node is actually the source address of the node, you can spoof the source address and the receiver will think the packet is coming from that spoofed address. Many programs for preparing spoofed IP datagrams are available for free on the Internet; for example, hping lets you prepare spoofed IP datagrams with just a oneline command, and you can send them to almost anybody in the world. You can spoof at various network layers; for example, you can use Address Resolution Protocol (ARP) spoofing to divert the traffic intended for one station to someone else. The Simple Mail Transfer Protocol (SMTP) is also a target for spoofing; because SMTP does not verify the sender's address, you can send any email to anybody pretending to be someone else. This article focuses on the various types of attacks that involve IP spoofing on networks...
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...SUBNETTING MADE EASY [pic] [pic] IP Classes The class system has become "old" in the ever demanding Internet paradigm, it has been (partially) replaced by CIDR system, which allows more efficient and practical allocation of IP addresses for the need of smaller networks. Nevertheless, it is important to know and understand what class system is and how it works, which has been the backbone of the IP. IP addresses have been classified into 5 classes and special purpose addresses, depending upon the value in the first octet. Viz- • Class A - This is a class for very large networks, such as IBM which holds IP addresses in the range - 9.0.0.0 - 9.255.255.255. (almost 16,777,216 IP addresses). First Octet - - The first octet is between 1 to 126. (Starts with binary bit - 0). Network Address - The n/w address is denoted by first 8 bits or first octet. Host/Node Address - Host address is denoted by last 24 bits or last 3 octets. This Network-Host IP configuration for class A can be shown as - network.host.host.host and each can have 1 to 3 decimals. Thus forming 126 network addresses (27 - 1) and each of them capable of having 16,777,214 (224 -2) host addresses. • Class B - This is a class for medium-sized networks. First Octet - - The first octet is between 128 to 191. (Starts with binary bits - 10). Network Address - The n/w address is denoted by first 16 bits or first 2 octets. Host/Node Address...
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...when the domain controller receives a query with the name of the computer. This guide explains how to set up DNS on a simple network that consists of a single domain. Contents Step-by-Step Guide for DNS in Small Networks 5 Planning DNS 6 Understanding the DNS namespace 6 Designing a DNS namespace 8 Creating an Internet DNS domain name 9 Creating internal DNS domain names 9 Creating DNS computer names 9 Installing and Configuring AD DS and DNS 11 Configuring Client Settings 19 Advanced DNS Configuration 27 Adding resource records 28 Automatically removing outdated resource records 29 Troubleshooting DNS 31 Step-by-Step Guide for DNS in Small Networks Domain Name System (DNS) is a system for naming computers and network services that maps those names to network addresses and organizes them into a hierarchy of domains. DNS naming is used on TCP/IP networks, such as the Internet and most corporate networks, to locate computers and services by using user-friendly names. When a user enters the DNS name of a computer in an application, DNS can look up the name and provide other information that is associated with the computer, such as its IP address or services that it provides for the network. This process is called name resolution. Name systems, such as DNS, make it easier to use network resources by providing users with a way...
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...which includes the async serial ports which are usually used with the dial up modems and synchronous telecom services. Using Ethernet, only on synchronous links, it will be able to use 100BASE-TX 4B/5B or 1000BASE- X 8B/10B encoding for making an Ethernet-like serial implication. And the result of this will be less efficient too. Point-to point protocol is a commonly used data link protocol for establishing direct connection. The connection authentication, encryption, transcription and compression are provided in by the PPP. The PPP is used in many types of networks like phone line, cellular telephone, serial cable, specialized radio links and fiber optical links. The PPP which is used over the Internet access is called broadband. The most commonly used forms of PPP by the Internet service providers are...
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...IP Addresses Classes and Special-Use IP Address Space The A, B, C IP address classes were first introduced in the 1970s as the original routing scheme to organize IP addresses into manageable, recognizable chunks. They were designed to signify different sizes of networks. Class A was for large networks that didn’t need many networks but instead needed a lot of hosts. Class B was medium sized with more networks but less hosts. Class C was for small organizations that needed many networks but few hosts. This system worked well until the 1990s when, due to demand, a classless system was developed called the CIDR (classless inter domain routing) system. CIDR allows for a more flexible allocation and customization of a network’s routing system. The address spaces are as follows: Class A’s first octet ranges from 1 to 126 Class B’s first octet ranges from 128 to 191 Class C’s first octet ranges from 192 to 223 Class D’s first octet ranges from 226 to 239 and are multicast addresses comprised of either pull or push types. A first octet that starts with 127, 224 and 225 are reserved for government use and testing. RFC 1918 IP address ranges are private and can be used within any network to subnet or expand their network. They will never go over the internet and are automatically dropped by any router connected to the internet. They are as follows: Class A = 10.0.0.1 through 10.255.255.254 Class B = 172.16.0.1 through 172.31.255.254 Class C = 192.168.0.1 through 192.168...
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...------------------------------------------------- Department of Electrical, Computer & Communications Engineering ------------------------------------------------- MSc Project Final Project Report ------------------------------------------------- Title: Secured infrastructure development for educational university using servers, firewalls and biometric devices ------------------------------------------------- ------------------------------------------------- ------------------------------------------------- Author: Azhar ur Rehman ------------------------------------------------- ------------------------------------------------- Academic Session: 2008-2009 ------------------------------------------------- Supervisor: Mr.Manoj Pongubhati Course Title: Msc computer systems and networking Mode of Study: Full Time ACKNOWLEDGEMENT First and foremost I would like to dedicate my thesis to my parents and want to thank Prof. Mr. Manoj pongubhati, my research dissertation supervisor, for giving me an opportunity to work on the dissertation of my interest and encouraging me throughout my work. His support and patience helped me overcome many difficult times during my dissertation research. I am also deeply grateful to Mr Ali Ahmed, a good friend and guardian who is working as an Assistant Manager with Dynamic Associates Info Pvt Ltd was actively involved with my research. The day I started working under the professional guidance of Dynamic...
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...automatically provides an Internet Protocol (IP) host with its IP address and other configurations information such as the subnet mask and default gateway. RFCs 2131 and 2132 define DHCP as an Internet Engineering Task Force (IETF) standard based on Bootstrap Protocol (BOOTP), a protocol which DHCP shares many operation details. DHCP allows hosts to obtain required TCP/IP configuration information from a DHCP server. Dynamically Host Configuration Protocol (DHCP) provides four key benefits to managing and maintaining a TCP/IP networks. Those four terms are centralized administration of IP configuration, Dynamic Host Configuration, Seamless IP host configuration, and Flexibility and Scalability. DHCP has reliable IP address configuration, which minimizes configuration errors caused by manual IP address configuration, such as address conflicts caused by the assignment of an IP address to more than one computer at the same time. DHCP also benefits in reducing network administration. DHCP reduce the network administration by using centralized and automated TCP/IP configuration. It has the ability to define the TCP/IP configurations from a central location and the ability to assign a full range of additional TCP/P configuration values by means of DHCP options. DHCP is safe and reliable configuration, and also reduces configuration management. Dynamic Host Configuration Protocol (DHCP) has some advantages over a statically assigning the client with an IP address. One advantage...
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