1. IPv4 addressing

Machines operating under the IP protocol have a 32-bit address. This address is often represented by a sequence of four numbers separated by dots; for example, 191.92.34.223.

The address is made up of two parts: a network identifier and an identifier for the machine within that network. The network identifier is preceded by a network class number. There are four address classes, each of which encodes a different number of networks and machines:

• class A – 128 networks (coded on 7 bits) and 16,777,216 hosts (coded on 24 bits);

• class B – 16,384 networks (14-bit coded) and 65,535 hosts (16-bit coded);

• class C – 2,097,152 networks (coded on 21 bits) and 256 hosts (coded on 8 bits);

• class D – group addresses (coded on 28...