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Successful Evaluations of .test IDN TLDs

In October 2006, ICANN engaged Autonomica AB of Stockholm, Sweden, to develop, conduct, and report on the results of laboratory testing of internationalized top-level domains in a setting corresponding to the public root. On 7 March 2007 the result of the laboratory tests were reported successfully. The laboratory technical test was one of the prerequisites to eventual insert internationalized top level labels in the root zone, which subsequently were done and the associated test facility was launched.

Following the project plan, Autonomica then conducted a replication of the laboratory test, live in the DNS. Quoting from their report:

"Autonomica AB has, under a contract with ICANN, investigated whether the addition of top level domains containing encoded internationalized characters (so called IDNs) to the public root zone for testing purposes has any impact on the iterative mode resolvers used to look up the information. No impact at all could be detected. All involved systems behaved exactly as expected."

Therefore, the Automomica test raised no issue regarding the ability of root-severs and iterative mode resolvers to handle IDN TLD queries.

Details of the test result can be found here [PDF, 129K].

For any questions or request for additional details of the test design and result please contact Tina Dam at

For further information around ICANN's IDN Program please visit

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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."