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Top-Level Domain

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Revision as of 19:32, 6 February 2011 by Andrew (talk | contribs)

Acronym: Top Level Domain

The TLD is always the last part of a domain name, such as .com, .net, .us, etc.[1]

Each TLD is managed by a single Registry.

History[edit | edit source]

The need for a hierarchical DNS arose with the popularity of the Internet in academic spheres in the early 1980s. This eventually necessitated a de-centralized Internet. Communications between The Stanford Research Institute NIC and other institutions include plans to create a hierarchical DNS, found in [RFC 805], a group document from 1982. This document outlines many of the basics of the eventual DNS, including the need for TLDs to provide a fixed starting point for queries, and the need for SLDs to be unique. This, in turn, would necessitate the need for a registrar type of administration, and help the nascent IT community recognize that the distribution of responsibility for each domain to individual name servers would provide administrative advantages.<ref>Living Internet

Varieties of TLDs[edit | edit source]

There are different types of TLDs.

These TLDs operate in different manners, and can be categorized in some simple ways:

  • Operating Mode
    • Open - Operating and offering both registration and resolution services.
    • Closed - Not Accepting registrations, may be resolving evergreen/legacy/infrastructure subdomains.
  • Level of Restriction
    • Unrestricted - If there are no requirements that must be met in order to register a name under a TLD, that TLD is Unrestricted.
    • Restricted - Requiring Local Physical Address, Local Tax ID, or other specific criteria be met to qualify in order to provision a name.
    • Sponsored - A variation on Restricted, the applicant for a domain in an STLD must meet the requirements within that TLD (ie. .jobs would require that Human Resources be involved, .travel would require certain Travel criteria are met, etc).


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