IDC, Inc. Domains

A domain name is the alphabetic equivalent of an address on the Internet. The name actually translates to a unique series of numbers (Internet Protocol Address).

Domain names are used instead of the IP primarily because people can more easily remember a word rather than a long set of numbers. The other reason is that a domain can be moved to a new server, that will have a new IP, but the name remains the same. The DNS (Domain Name System) server that translates domain names into the IP addresses.

Domain names have a least two parts that are separated by a dot. The part after the dot is called the TLD (Top Level Domain), which is used to broadly categorize the name to its purpose or type. The most common TLDs are .com (commercial), .org (organization), and .net (network). The part before the dot is called the SLD (Second Level Domain), which can contain up to 24 characters (letters, numbers, and dashes) and must be unique in its TLD.

The databases of domain records are maintained by InterNIC and other similar agencies around the world. The contents of the databases are accessed through a program called Whois that is offered through a number of gateways.