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 its top-level domain (TLD), and every TLD is managed by a single [[registry]

Overview from 1983 to 2021

Dates	TLDs	use	reason	significance
1983	.no	ccTLD	Norway	the first ccTLD
October 1984	introduced: .com, .net, .org	open	any person or entity is permitted to register	the original TLDs
October 1984	introduced: .edu, .gov, .mil	limited (sponsored)	for higher educational institutions, United States governmental entities and agencies, and divisions, services and agencies of the United States Department of Defense, respectively	the original TLDs
1985	.us, .uk .il	ccTLDs	USA, UK, Israel	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 8 ccTLDs
November 3, 1988	introduced: .int	limited (sponsored)	for organizations, offices, and programs endorsed by a treaty between two or more nations	in response to NATO request
1998				Domain deregulation; ICANN is formed to oversee Internet names and numbers
May 2000	.arpa	limited (sponsored)	all Internet infrastructure databases
November 16, 2000	approved: .aero, .biz, .coop, .info, .museum, .name, .pro	sponsored gTLDs
	Approved: .asia, .cat, .jobs, .mobi, .tel, .travel	sponsored gTLDs
April 2011	introduced: .xxx	sponsored gTLD		ICM Registry had been submitting this sTLD for pornographic sites since 2000
2012	introducted: .post	sponsored gTLD
		Community TLDs	for a defined community consisting of a restricted population
June 20, 2011				ICANN Board votes to dramatically increase the number of gTLDs from the 22 already in operation
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 new gTLD 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.

• ccTLDs with ASCII characters

TLDs with two ASCII characters have been established for over 250 countries and external territories.

• IDN ccTLDs

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