Dotteddecimal

Dotteddecimal is a textual representation of an IPv4 address in which four decimal octets are separated by periods. Each octet is a base-10 number from 0 to 255, corresponding to one 8-bit byte of the 32-bit address. For example, 192.168.0.1 encodes a 32-bit value whose bytes are 192, 168, 0, and 1. Dotteddecimal is widely used for human readability and configuration of networking devices, such as routers, switches, computers, and servers. In addition to addresses, subnet masks and broadcast addresses are commonly written in dotteddecimal form (for example 255.255.255.0 or 255.255.254.0).

Operationally, dotteddecimal addresses are tied to binary representations. To convert, each decimal octet is translated to its 8-bit binary equivalent, and the four octets are concatenated to form the 32-bit address. The format is specific to IPv4; IPv6 uses colon-separated hexadecimal notation rather than decimal dotted notation.

Caveats include potential confusion from leading zeros, where some implementations may interpret 010 as octal rather than decimal. Leading zeros are often discouraged or disallowed in configuration tools. Dotteddecimal provides readability but is not scalable for future addressing schemes, hence IPv6 uses a different representation. In subnetting, a dotteddecimal address may be paired with a prefix length, such as 192.0.2.0/24, to denote a network. The dotteddecimal address itself does not specify a network boundary; the prefix length does.

See also: IPv4, subnet mask, CIDR notation, IP address.