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. An IP address can be set manually or assigned through a DHCP server.

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.