The Internet is growing. In the 1980s and 1990s, the number of top-level domains was small and the format of domain names was simple. All domains ended with one of a number of common endings like ".com" and ".net", or a two-letter country code like ".de" or ".uk". Times have changed. Since 2001, new types of domains have been introduced:
- ASCII TLDs of more than 3 letters long (think of ".info" or ".museum"); and
- since 2010, TLDs comprised of non-Latin characters (such as".中国" and".рф").
The ICANN Board's approval of the new gTLD program in 2011 will allow for hundreds of additional TLDs to be added. This means that the variety of domain names will expand even further.
However, the cooperation of software vendors, web site developers and others is required so that these new TLDs are available to all that would use them. In many cases, there is a sort of "check" imposed whenever you type a name into your browser. The purpose of the check is to screen invalid domain names before a DNS query is sent. Some of these checks still do not allow for all domains such as the newer ones that are four or more characters or are in languages other than those using Latin characters.
Those constraints imposed in software on what is allowed as a valid domain name (such as limiting domains to specific endings like ".com") are artificially constraining the growth and utility of the Internet. The Universal Acceptance effort aims to ensure those constraints are lifted:
- first, by recommending against software performing checks on domain name validity unless it is truly required, and
- second, that if checks need to be performed, it is done in a way that allows for all domains to function correctly, whether they were registered 20 years ago, or more recently.
Most software should not need to test whether a domain name is valid. The act of connecting to a domain name (in the case of a URL, for example), or sending an email (in the case of an email address) will automatically provide mechanisms of informing if the domain name is valid or not.
If there is a need to check domain validity, it is most desirable that the DNS protocol is used for that purpose. If, however, there is a specific requirement to only check the validity of the top-level domain, 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 ICANN's IANA function and provides a regularly-updated list 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.
Cooperation among registry operators, ISPs, software developers, vendors, 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.
This webpage will be updated to reflect progress on this topic. To submit questions or contribute additional material that may be helpful in further work on this, please email to: firstname.lastname@example.org
Releases Beta-3 Version of TLD Verification Code
22 March 2007
ICANN has issued today a new version of code intended to assist software developers and application providers whose work assists others in using the DNS.
Beta TLD Verification Tool
3 December 2006
Today ICANN released a beta version Top-Level Domain (TLD) Verification Tool. This verification tool has been developed in response to problems reported by gTLD registries and end-users of the non-acceptance of some existing TLDs. These problems occur in some current applications because: 1) they do not recognize any TLD of more than three characters; or, 2) they rely on legacy information where only com/net/org and a handful of ccTLDs are recognized as valid.
Area on Universal Acceptance of TLDs
20 March 2006
In order for the full resources of the Internet to be available to all users globally, service and application providers must make use of the complete range of top-level domains (TLDs). To promote accessibility of up-to-date TLD information, ICANN is making available a new page of resources related to this topic.
Acceptance of all gTLD Names
18 October 2004
- IANA List of Delegated Top-Level Domains
- IANA Reports
- ICP-3: A Unique, Authoritative Root for the DNS
- Keeping the Internet A Reliable Global Public Resource: Response to New.net Policy Paper
- RFC 3696
- TLD-Acceptance Discussion Forum
- TLD Verification Tool
- Why universal resolvability is important (a non-technical explanation)