Chapter 3. IP

Addressing

IPv4 addresses

IPv4 addresses consist of 32 bits. These 32 bits are divided into four sections of 8 bits, each called an octet. Addresses are typically represented in dotted-decimal notation. For example:

10.200.34.201

Subnet masks identify which portion of the address identifies a particular network and which portion identifies a host on the network.

The address classes defined for public and private networks consist of the following subnet masks:

Class A 255.0.0.0 (8 bits)

Class B 255.255.0.0 (16 bits)

Class C 255.255.255.0 (24 bits)

Class A addresses begin with 0 and have a first octet in decimal of 1 to 127. Class B addresses begin with 10 and range from 128 to 191. Class C addresses begin with 110 and range from ...

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