The addresses are called IP numbers. An IP number has four 'digits', with each digit represented by a number from 0 to 255. The smallest IP number is 0.0.0.0 The largest one is 255.255.255.255 The computer that this document was written on has an IP number of 134.68.140.61 These numbers are used very much like a zip code to help a packet of information find its way to the proper destination.