IP address
An Internet Protocol address (IP address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.
An IP address serves two principal functions: host or network interface identification and location addressing.
Classless Inter-Domain Routing
An IP address is part of a CIDR block, and is said to match the CIDR prefix if the initial "n" bits of the address and the CIDR prefix are the same. An IPv4 address is 32 bits so an "n"-bit CIDR prefix leaves 32 − "n" bits unmatched, meaning that 2 IPv4 addresses match a given "n"-bit CIDR prefix. Shorter CIDR prefixes match more addresses, while longer prefixes match fewer. An address can match multiple CIDR prefixes of different lengths.