Domain Name System (DNS) definitions

Domain Name

The name referring to an entity on the Internet. It normally consists of a sequence of labels separated by periods (dots), e.g., www.k-state.edu and zaurak.cis.k-state.edu. It is a hierarchical naming system - for example, the top-level domain ".edu" refers to all higher education institutions in the United States. "k-state.edu" refers to everything at K-State. "cis.k-state.edu" identifies everything in the Computing and Information Sciences department, and "zaurak.cis.k-state.edu" refers to a specific computer in that department. All domain names must be unique.

Domain Name System (DNS)

People like to use names when referring to a site on the Internet, like www.k-state.edu to refer to the K-State web server, while machines prefer to work with numbers, like 129.130.12.27 (aka, the "IP address"). DNS is a distributed database that stores information about entities on the Internet that are referenced by their domain name. Its most common use is to simply translate the domain name into its corresponding IP address which the network devices use to deliver the information over the Internet.

Domain Registrar

A company authorized to accept registrations for new domain names, guaranteeing they are unique and made known to the DNS servers on the Internet. Registrars generally only register "second-level domains", which are names with only two parts like "k-state.edu, "microsoft.com", and "k-state.org".

Top-Level Domain (TLD)

The right-most label in a domain name. The primary TLDs in the U.S. are:

• .com for commercial, for-profit entities
• .org for miscellaneous, usually non-profit, organizations
• .net for network infrastructure machines and service providers
• .edu for degree-granting institutions (only one, or in rare cases two, are allowed per institution)
• .gov for U.S. federal government agencies (limited purposes)
• .mil for U.S. military (limited purposes)
• .int for organizations established by internal treaties between governments (limited purposes)
• .coop for cooperatives
• .info an unrestricted top-level domain for businesses, marketers, trademark owners, individuals, organizations
• .museum for museum, museums associations, and museum professionals
• .pro for accountants, lawyers, physicians, and other professionals

Each country also has its own TLD, such as .us for the United States, .uk for the United Kingdom, or .fr for France.

See the complete list of top-level domains from the Internet Assigned Numbers Authority (IANA).