In order for the full resources of the Internet to be globally available for all users, service and application providers must make use of the complete range of top-level domains (TLDs).

A current list of all top-level domains that have been delegated within the authoritative root-server system is available here. This list is maintained by the IANA and provides a regularly-updated index of TLDs that currently exist in the root zone.

Rejection of some TLD strings due to outdated length parameters or other erroneous formatting criteria can be avoided by reliance on authoritative information. As described in Support of New Top-Level Domains by Internet Infrastructure Operators and Application Providers (2003), and Evaluation of New gTLDs (2004), several technical acceptance issues were associated with the gTLDs introduced in 2000-2001. This was particularly true for TLDs of more than 3 characters.

Cooperation among registry operators, ISPs, and others who deal with domain names on a regular basis is critical to ensuring the continued realization of the Internet's potential for commerce and communications. In October of 2004, ICANN opened a discussion forum on TLD acceptance issues to foster cooperation among the necessary parties. The archive of this discussion forum is available here. To join this discussion list, simply send a message to <majordomo@icann.org> with the words "subscribe tld-acceptance" in the body of the message.

To submit questions or contribute additional material that may be helpful in further work on this subject, please contact ICANN.