Ip Location

Uniform allocation of IP across the network

IP Configuration by DHCP

When an IP-based local area network is installed, each computer must be configured with an IP address. If the computers need to access the Internet, they should also be configured with a gateway address and one or more DNS server addresses. As an alternative to manual configuration, Dynamic Host Configuration Protocol (DHCP) is a method by which each computer on the network can automatically obtain this configuration information. A device on the network may act as a DHCP server. The DHCP server stores a list or pool of IP addresses, along with other information (such as gateway and DNS addresses) that it may assign to the other devices on the network.

Internet Protocol (IP) Addresses

Because TCP/IP networks are interconnected across the world, each computer on the Internet must have a unique address (called an IP address) to make sure that transmitted data reaches the correct destination. Blocks of addresses are assigned to organizations by the Internet Assigned Numbers Authority (IANA). Individual users and small organizations may obtain their addresses either from the IANA or from an Internet service provider (ISP). The current Internet Protocol (IPv4) uses a 32-bit address structure. The address is usually written in dot notation (also called dotted-decimal notation), in which each group of eight bits is written in decimal form, separated by decimal points. For example, the following binary address:

11000011 00100010 00001100 00000111 is normally written as: 195.34.12.7. The latter version is easier to remember and easier to enter into your computer. In addition, the 32 bits of the address are subdivided into two parts. The first part of the address identifies the network, and the second part identifies the host node or station on the network. The dividing point may vary depending on the address range and the application. There are five standard classes of IP addresses. These address classes have different ways of determining the network and host sections of the address, allowing for different numbers of hosts on a network. Each address type begins with a unique bit pattern, which is used by the TCP/IP software to identify the address class. After the address class has been determined, the software can correctly identify the host section of the address. The figure below shows the three main address classes, including network and host sections of the address for each address type. The five address classes are:

• Class A - can have up to 16,777,214 hosts on a single network. They use an 8-bit network number and a 24-bit node number. Class A addresses are in this range: 1.x.x.x to 126.x.x.x.
• Class B - can have up to 65,354 hosts on a network. A Class B address uses a 16-bit network number and a 16-bit node number. Class B addresses are in this range: 128.1.x.x to 191.254.x.x.
• Class C - can have up to 254 hosts on a network. A Class C address uses a 24-bit network number and an 8-bit node number. Class C addresses are in this range: 192.0.1.x to 223.255.254.x.
• Class D - are used for multicasts (messages sent to many hosts). Class D addresses are in this range: 224.0.0.0 to 39.255.255.255.
• Class E - are for experimental use. This addressing structure allows IP addresses to uniquely identify each physical network and each node on each physical network. For each unique value of the network portion of the address, the base address of the range (host address of all zeros) is known as the network address and is not usually assigned to a host.

Also, the top address of the range (host address of all ones) is not assigned, but is used as the broadcast address for simultaneously sending a packet to all hosts with the same network address.