IP Address Classes

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Introduction

IP addresses are divided into address classes that broadly allocate groups of IP addresses, so that an address that begins with the byte 191, for example, belongs to a class B network. CIDR is no addressing problems such as class B exhaustion by grouping contiguous class C addresses into a single network allocation.

IP Address Classes

IP Address Classes
Class	Address Range	Allocation
Class A	1-126.xx.xx.xx	16 million host network
Class B	128-191.xx.xx.xx	65536 host network
Class C	192-223.xx.xx.xx	256 host network
Class D	224-239.xx.xx.xx	multicast
Class E	240-255.xx.xx.xx	reserved