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Single-Letter Domains

Open: 16 October 07
Closed: 15 November 07
Extended to
15 December 07

Explanation:ICANN is looking for ideas and suggestions on ways to allocate single-letter domains, such as,, or Currently, it is not possible to register single-letter domains in all 16 generic top-level domains, from .aero to .travel - a policy stretching back to pre-ICANN days.

However, a recent report [pdf] by a working group of the GNSO recommended that single-letter domains be made available now and into the future, with the proviso that an appropriate allocation method was devised. This forum is therefore asking the community for suggestions on what allocation methods it feels would be best. ICANN will synthesize responses and then present proposed methods for allocation for community consideration.

For more information and background, see the official announcement of this forum.

Staff member responsible: Patrick Jones

Announcement | Comments | Summary/analysis of comments

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."