This domain is therefore almost exclusively used by American colleges 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. edu TLD is limited to specific higher educational institutions such as, but not limited to, trade schools and universities. However, a few grandfathered domains do not meet these criteria. int TLD is strictly limited to organizations, offices, and programs endorsed by a treaty between two or more nations. 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. 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. It was originally administered by the United States Department of Defense. Domain name registrations may be successfully challenged if the holder cannot prove an outside relation justifying reservation of the name, to prevent ' squatting'.

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. DNSSEC: presence of DS records for Domain Name System Security Extensions.

IDN: support for internationalized domain names (IDN).

Seven generic top-level domains were created early in the development of the Internet, and predate the creation of ICANN in 1998.

generic-restricted top-level domains (grTLD).

IANA distinguishes the following groups of top-level domains:

Qq international online