IP Addresses (and misaddresses)
Putting the litigious confusion of domain names, trademarks and copyright behind us, we will now turn our attention to IP addressing.
On an isolated network, ie. an office LAN, IP addresses can be assigned randomly on the condition that each IP address remains unique. Once you go to the outside world through the Internet things start to get complicated. When connecting such a private network to the outside world you must use registered IP addresses, referred to as called Internet Addresses, to avoid duplication with everyone else that is already on line.
Basically an IP address is an identifier for a computer or device on a TCP/IP network and these networks route traffic on the basis of the IP address of the destination. IP addresses are based on a 32-bit numeric address written as four numbers separated by periods where each number can be zero to 255. For example, 10.100.101.201 could be a valid IP address.
Obviously its easier for us to remember decimals than binaries, but the binary representation of the IP address is important as it determines which class of network the IP address belongs to. An IP address has two parts, one identifying the network and one identifying the node, or host. The Class of the address determines which part belongs to the network address and which part belongs to the node address. All nodes on a given network share the same network prefix but must have a unique host number.
Class A networks have a binary address starting with zero, so the decimal number can be anywhere from 1 to 126. The first eight bits identify the network and the remaining 24 bits indicate the host within the network. An example of a Class A IP address is 188.8.131.52, where 101 identifies the network and 138.223.201 identifies the host on that network.
Class B networks have a binary addresses starting with 10, so the decimal number can be anywhere from 128 to 191. (127 is reserved). The first 16 bits identify the network and the remaining 16 bits indicate the host within the network. An example of a Class B IP address is 184.108.40.206 where 151.138 identifies the network and 223.201 identifies the host on that network.
Class C networks have a binary addresses starting with 110, therefore the decimal number can be anywhere from 192 to 223. The first 24 bits identify the network and the remaining eight bits indicate the host within the network. An example of a Class C IP address is 220.127.116.11 where 201.138.223 identifies the network and 101 identifies the host on that network.
Class D networks have a binary addresses starting with 1110, therefore the decimal number can be anywhere from 224 to 239. Class D networks are used to support multicasting.
Class E networks have a binary addresses starting with 1111, therefore the decimal number can be anywhere from 240 to 255. Class E networks are used for experimentation and have not been documented or utilised in a standard way.
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