domain namesA domain name is an alias used by TCP/IP applications that identifies a group or organization connected to the Internet. A domain is an address that represents a group of Internet users, and the name is an alias given to that address to prevent having to remember clumsy groups of numbers. Names are typically easier to manage and provide more useful information than IP addresses. For example, my domain might be 205.231.222.35, but my domain name might be lanwrights.com. The extension portion of the domain name (.com) denotes that this domain name is a commercial entity.
Domain names need to be unique and must be registered with InterNIC. Typically, a local ISP can handle this for an individual, but organizations would typically file their own registration. Domain Name registration costs $100.00 and remain valid for a two year period. In addition to that charge, maintenance costs ($50.00/year) are assessed and service charges may be levied by ISP's to perform the registration on behalf of an organization. On-line searches can be performed through InterNIC's WHOIS to see if the proposed domain name is already in use.
Domain names follow a hierarchical structure with the top five world-wide levels consisting of "COM", "ORG", "NET", "EDU", "INT". The US has two additional levels: "MIL" and "GOV". In addition, country codes using two letter designations are included (i.e., US for United States).
RFCs relating to the Domain Name System are RFCs 1031 through 1035, RFC 1480, and RFC 1591.