IP address

An IP address is the 32-bit number uniquely identifying a on a network using Internet Protocol, as defined in STD 5, RFC 791. An IP address is normally displayed in dotted decimal notation, e.g. 128.121.4.5.

Description
The address can be split into a network number (or ) and a host number unique to each host on the network and sometimes also a.

The way the address is split depends on its "class", A, B or C (but see also CIDR). The class is determined by the high address bits:
 * Class A - high bit 0, 7-bit network number, 24-bit host number. n1.a.a.a 0 <= n1 <= 127
 * Class B - high 2 bits 10, 14-bit network number, 16-bit host number. n1.n2.a.a 128 <= n1 <= 191
 * Class C - high 3 bits 110, 21-bit network number, 8-bit host number. n1.n2.n3.a 192 <= n1 <= 223

DNS translates a node's fully qualified domain name to an Internet address which (ARP, or constant mapping) translates to an Ethernet address.