Every computer must have a unique number in order to work properly in a network or on the Internet. This number is called address because it makes possible for a computer to be found by other computers – ( like the human addresses! ) – and to establish a communication with them.
So we have IP address: Internet Protocol address. This number is in the form of XXX . XXX . XXX . XXX where XXX is an integer number between 0 and 255. ( DOTTED QUAD: four group of decimal numbers separated by a dot ). Computers don’t understand our decimal system but only electrical signals like on – off, so we must use the binary system (base 2 not base 10) where a number is composed by a series of 0 and 1. Example: 7 is represented by 00000111. Every binary cypher, that is 1 or 0, is a bit and 8 bits makes one byte. So 255 is,in binary,11111111. Since every group of the IP address is formed by 8 bits and there are four groups (or four bytes ), we say that an IP address is 32 bits long ( 8 x 4 = 32 ). Example 192.0.2.79 , in binary, looks like this: 11000000000000000000001001001111 Since there are 2 cyphers – 0 and 1 – it is possible to have 4.294.967.296 ( 2^32 ) of different combinations of addresses.
