CIDR (Classless Inter-Domain Routing)

CIDR notation is a compact representation of an IP address and its associated routing prefix. represents the IPv4 address and its associated routing prefix, or equivalently, its subnet mask, which has 24 leading 1-bits.

The number of addresses of a subnet may be calculated as 2address length − prefix length, where address length is 128 for IPv6 and 32 for IPv4. For example, in IPv4, the prefix length /29 gives: 232 − 29 = 23 = 8 addresses.


Igor Springer

I build web apps. From time to time I put my thoughts on paper. I hope that some of them will be valuable for you. To teach is to learn twice.