Appendix D. IP Addresses and Ranges Format

Table of Contents
IPv4 Addresses and Ranges
IPv6 Addresses and Ranges

IPv4 Addresses and Ranges

An IPv4 address is made of 4 numbers separated by dots as in aaa.bbb.ccc.ddd, each number ranges from 0 to 255.

An IPv4 address range must conform to one of the following forms:

Example D-1. CIDR Notation Example represents IPv4 addresses between and Actually, in binary is 11011100 01001110 10101000 00000000. So includes all the IPv4 addresses which 21 first bits are 11011100 01001110 10101. Therefore, it represents the range (in binary 11011100 01001110 10101000 00000000 - 11011100 01001110 10101111 11111111.)