This list of Internet top-level domain (TLD) extensions contains top-level domains, which are those domains in the DNS root zone of the Domain Name System of the Internet. The official list of all top-level domains is maintained by the Internet Assigned Numbers Authority (IANA) at the Root Zone Database.[1][2] IANA also oversees the approval process for new proposed top-level domains. As of April 2018, the root domain contains 1543 top-level domains,[3] while a few have been retired and are no longer functional. Original top-level domains Seven generic top-level domains were created early in the development of the Internet, and predate the creation of ICANN in 1998. Name: DNS names Entity: intended use Notes: general remarks IDN: support for internationalized domain names (IDN) DNSSEC: presence of DS records for Domain Name System Security Extensions Name Entity Administrator[5] Notes IDN DNSSEC .com commercial Verisign This is an open TLD; any person or entity is permitted to register. Though originally intended for use by for-profit business entities, for a number of reasons it became the "main" TLD for domain names and is currently used by all types of entities including nonprofits, schools, and private individuals. Domain name registrations may be successfully challenged if the holder cannot prove an outside relation justifying reservation of the name[citation needed], to prevent "squatting". It was originally administered by the United States Department of Defense. Yes Yes .org organization Public Interest Registry This is an open TLD; any person or entity is permitted to register. Originally intended for use by non-profit organizations, and still primarily used by some. Yes Yes .net network Verisign This is an open TLD; any person or entity is permitted to register. Originally intended for use by domains pointing to a distributed network of computers, or "umbrella" sites that act as the portal to a set of smaller websites. Yes Yes .int international organizations Internet Assigned Numbers Authority The .int TLD is strictly limited to organizations, offices, and programs endorsed by a treaty between two or more nations. However, a few grandfathered domains do not meet these criteria. No Yes .edu education Educause (via Verisign) The .edu TLD is limited to specific higher educational institutions such as, but not limited to, trade schools and universities. In the U.S., its use was restricted in 2001 to post-secondary institutions accredited by an agency on the list of nationally recognized accrediting agencies. This domain is therefore almost exclusively used by American colleges and universities. Some institutions, such as the Exploratorium, that do not meet the current registration criteria have grandfathered domain names. No Yes .gov U.S. national and state government agencies General Services Administration (via Verisign) The .gov TLD is limited to United States governmental entities and agencies as well as qualifying state, county and local municipal government agencies. No Yes .mil U.S. military United States Department of Defense The .mil TLD is limited to use by the United States military. No Yes Infrastructure top-level domain Infrastructure Entity Notes IDN DNSSEC .arpa "Address and Routing Parameter Area" Originally assigned to the Advanced Research Projects Agency in the early days on the Internet, .arpa is now exclusively used as an Internet infrastructure TLD. No Yes Country code top-level domains As of May 20, 2017, there were 255 Country code top-level domains. (For comparison, at the same time the United Nations comprised 193 countries.) Table legend Name DNS name of the two-letter country-code top-level domain. They follow ISO 3166-1 alpha-2, with some exceptions. Entity Country, dependency, or region Explanation Explanation of the code when it is not self-evident from the English name of the country. These are usually domains that arise from native name of the country (e.g. .de for Deutschland, German name for Germany). Notes General remarks IDN Support for internationalized domain names (IDN) DNSSEC Presence of DS records for Domain Name System Security Extensions SLD Allows second-level domain registration (restrictions may apply) IPv6 Registry fully supports IPv6 access A Name Entity Explanation Notes IDN DNSSEC SLD

• published: 05 Jul 2018
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