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.
Varieties of TLDs
There are different types of TLDs.
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.
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 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).