Top-Level Domain
The domain name system allows users to refer to websites and other Internet resources using names rather than the all-numeric IP addresses assigned to each computer on the Internet. Each domain name consists of a series of character strings separated by dots. The right-most string is the top-level domain (TLD). Every TLD is managed by a single registry.
A central part of IANA's function is to establish baseline standards for eligible TLDs. These standards are largely unchanged since the inception of ICANN, and are based on Jon Postel's RFC 1591.[1] A central value of the Internet, and organizations dedicated to its maintenance, is the stability and security of the root zone; as a result, the policies and principles memorialized in RFC 1591 are largely followed today.[2][3][4]
TLD Growth - Overview from 1983 to 2021
| Dates | TLDs | Use | Reason | Significance |
|---|---|---|---|---|
| 1983 | .no | country code TLD | Restricted to use by entities in Norway | The first ccTLD |
| October 1984 | .com, .net, .org | Open | Any person or entity is permitted to register a domain name using these TLDs | The first gTLDs |
| October 1984 | .edu, .gov, .mil | Limited; an entity has sponsored the operation of this TLD | For higher educational institutions, United States governmental entities and agencies, and divisions, services and agencies of the United States Department of Defense, respectively | The first gTLDs |
| 1985 | .us, .uk .il | ccTLDs | USA, UK, Israel | The second, third, and fourth ccTLDs |
| 1986 | .au, .de, .fi, .fr, .is, .kr, .nl, .se | ccTLDs | Australia, Denmark, Finland, France, Iceland, South Korea, Netherlands, Sweden | The next eight ccTLDs |
| November 3, 1988 | .int | Limited; sponsored | For organizations, offices, and programs endorsed by a treaty between two or more nations | In response to a request by NATO |
| 1998 | -- | -- | -- | Domain deregulation; ICANN is formed to oversee Internet names and numbers |
| May 2000 | .arpa | Limited; sponsored | All Internet infrastructure databases | one of the original TLDs, .arpa was re-designated at this time as an Address and Routing Parameter Area, critical to maintaining the stability of the Internet |
| November 16, 2000 | .aero, .biz, .coop, .info, .museum, .name, .pro | Sponsored gTLDs | ||
| 2005-2007 | .cat, .eu, .asia | Sponsored specifically for a cultural, ethnic, or regional group | Represents Catalan language and culture, the countries in the European Union, and the Asian continent, respectively | The first TLDs to denote geographical, geopolitical, ethnic, social, or cultural representation |
| .jobs, .mobi, .tel, .travel | limited to entities having something to do with the phrase comprising the TLD in question | |||
| April 2011 | .xxx | Sponsored gTLD | ICM Registry had submitted proposals for this sTLD for pornographic sites since 2000 | |
| June 20, 2011 | ICANN Board votes to dramatically increase the number of gTLDs from the 22 already in operation | |||
| January 12, 2012 | community or standard | applicant decides if the nTLD is for a defined community consisting of a restricted population; the distinction between sponsored/unsponsored TLDs is deemed irrelevant to this round of nTLDs | The application window for All New gTLD Applications opens | |
| June 13, 2012 | -- | -- | -- | Reveal Day: 1,930 applications for new gTLDs submitted; 751 of which were contest |
| July 15, 2013 | .сайт, .онлайн, .شبكة, .游戏 | -- | -- | First four IDN nTLD aggreements signed |
| November 9, 2014 | -- | -- | -- | 400th gTLD was delegated |
| 20 May 2017 | ccTLDs | -- | -- | 255 ccTLDs delegated |
| June 2020 | IDN ccTLDs | -- | -- | 61 IDN ccTLDs approved |
| March 2021 | -- | -- | -- | IANA lists 1589 TLDs (1503 in use, 67 not assigned/revoked, 8 retired, 11 test domains) |
Varieties of TLDs
There are different types of TLDs.
gTLDs
- brand TLDs - corporations use their corporate name as their website's top-level identifier instead of .com or .biz domain space
- community TLDs relate to local events, gatherings, or organizations.
- geoTLDs represent geographical or regional areas that are not countries with three or more ASCII characters.
- hSTLDs
- nTLDs - domains that were introduced beginning in October 2013
- sTLDs - has a sponsor for a specific purpose, such as to represent a specific ethnic community, professional group, or geographical location.
ccTLDs
Country-code TLDs are delegated to a designated ccTLD registry, which is operated by a ccTLD Manager, according to local policies that are adapted to meet the economic, cultural, linguistic, and legal circumstances of the country or territory involved.
- TLDs with two ASCII characters have been established for over 250 countries and external territories.
- TLDs with non-ASCII characters designated for a country or geographic region.
Operating Mode
TLDs operate in different manners but can be categorized in some simple ways:
- 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 to qualify.
Reserved Names
- country code top-level domains
- related to ICANN
- related to IANA functions
- names of countries and territories
- names of international and intergovernmental organizations
- names that a registry operator uses to operate the gTLD
- ↑ IANA.org - Root Zone Management
- ↑ See, for example, the Internet Society's IANA Timeline, covering the development of the RFC in 1994, and the subsequent "New Registries and the Delegation of International Top Level Domains," drafted by Postel in 1996.
- ↑ IETF.org - RFC 1591
- ↑ IETF.org - IANA-ITLD-Admin-01