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Registry and Registrar WHOIS Service Clarifications

ICANN announces clarifications to the WHOIS specifications in ICANN agreements.

To help support registry and registrar implementation and ease the path for compliance with the specifications, ICANN is announcing clarification to the Registration Data Directory Service (RDDS), which is commonly known as WHOIS. The clarifications are in response to input from both registries and registrars regarding the RDDS specification and intended to aid contracted parties in complying with Registry Agreements (RA) and Registrar Accreditation Agreements (RAAs).

The document, "Clarifications to the New gTLD Registry Agreement, Specification 4; and the 2013 Registrar Accreditation Agreement (RAA), Registration Data Directory Service (WHOIS) Specification" is published at

Most of the clarifications apply to both registries and registrars; however, the clarifications described in the second section only apply to registries, while the third section only applies to registrars. ICANN recognizes these clarifications may take some time to implement in active systems and is providing notice that it will begin enforcing compliance with these items as of 12 February 2015. One of the objectives of these clarifications is to retain the ability to easily parse the output. Interested users are encouraged to consider the clarifications when developing parsers for RDDS output.

There are 37 clarifications specified in the advisory, with some being required and others being optional. The document includes, but is not limited to, clarifications relating to formatting guidelines, field definitions, service level requirements, and pre-delegation testing specifications.

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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."