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Universal Acceptance of All TLDs – Prague Meeting

Universal acceptance of all top-level domains is an on-going initiative within ICANN. Our goal is to raise awareness among all Internet users about the diversity of domains on the Internet. In the 1980s and 1990s the number of top-level domains (TLDs) was small and they all shared the same basic format – two-character ASCII country code TLDs (ccTLDs) or a handful of three-character ASCII generic TLDs (gTLDs). This standard format led software vendors and web site developers to build their programs making specific assumptions about what was considered a valid TLD. As long as the software recognized the TLDs, people were able to use them. In the past decade newer ASCII gTLDs longer than three characters were introduced, plus new domains written in various non-Latin scripts — known as Internationalized domain names (IDNs) – were added. In the not so distant future we will be seeing even more TLDs, including IDN TLDs, thanks to the new gTLD program and IDN ccTLD Fast Track Process. This is why ICANN is committed to raising awareness among Internet software developers so they can build their software to ensure compatibility with all domains, rather than relying on outdated assumptions.

During the ICANN meeting in Costa Rica we held a roundtable discussion on TLD Acceptance. A panel of experts shared their experiences with the issue. We heard many suggestions on how to better guide our efforts in raising awareness of this initiative from the experts as well as from the community.

At the upcoming ICANN meeting in Prague we will not have a session specific to this topic. Instead we are reaching out to groups such as The At-Large Advisory Committee (ALAC), Country Code Names Supporting Organization (ccNSO) and others in order to schedule times to talk with them about the initiative and how they can help raise awareness.

If you have any questions about this effort or would like to schedule a time during the Prague meeting to learn more about the initiative and how you can help raise awareness, please contact ICANN staff at

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Domain Name System
Internationalized Domain Name ,IDN,"IDNs are domain names that include characters used in the local representation of languages that are not written with the twenty-six letters of the basic Latin alphabet ""a-z"". An IDN can contain Latin letters with diacritical marks, as required by many European languages, or may consist of characters from non-Latin scripts such as Arabic or Chinese. Many languages also use other types of digits than the European ""0-9"". The basic Latin alphabet together with the European-Arabic digits are, for the purpose of domain names, termed ""ASCII characters"" (ASCII = American Standard Code for Information Interchange). These are also included in the broader range of ""Unicode characters"" that provides the basis for IDNs. The ""hostname rule"" requires that all domain names of the type under consideration here are stored in the DNS using only the ASCII characters listed above, with the one further addition of the hyphen ""-"". The Unicode form of an IDN therefore requires special encoding before it is entered into the DNS. The following terminology is used when distinguishing between these forms: A domain name consists of a series of ""labels"" (separated by ""dots""). The ASCII form of an IDN label is termed an ""A-label"". All operations defined in the DNS protocol use A-labels exclusively. The Unicode form, which a user expects to be displayed, is termed a ""U-label"". The difference may be illustrated with the Hindi word for ""test"" — परीका — appearing here as a U-label would (in the Devanagari script). A special form of ""ASCII compatible encoding"" (abbreviated ACE) is applied to this to produce the corresponding A-label: xn--11b5bs1di. A domain name that only includes ASCII letters, digits, and hyphens is termed an ""LDH label"". Although the definitions of A-labels and LDH-labels overlap, a name consisting exclusively of LDH labels, such as"""" is not an IDN."