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Implementation Project Status

Updated 7 May 2019

Implementation of Policy Recommendation 1 of the Thick WHOIS Policy Development Process Final Report [PDF, 1.2 MB] includes two outcomes: the "Transition from Thin to Thick for .COM, .NET, and .JOBS" and the "Consistent Labeling and Display of WHOIS Outputs for all gTLDs":

"The provision of thick WHOIS services, with a consistent labeling and display as per the model outlined in specification 3 of the 2013 [Registrar Accreditation Agreement], should become a requirement for all gTLD registries, both existing and future."

The policies require all gTLD registrations to be "thick," with a consistent labeling and display of WHOIS outputs. Those gTLD registry operators currently providing thin WHOIS services – .COM, .NET and .JOBS – must submit all new domain name registrations as Thick WHOIS. These registries must also migrate all data required for Thick WHOIS services for existing domain names.

Transition from Thin to Thick for .COM, .NET and .JOBS

Thick WHOIS Implementation Project Status: Analyze and Design

Consistent Labeling and Display of WHOIS output for all gTLDs

Thick WHOIS Implementation Project Status: Support and Review


  • Board Approval of Policy Recommendations: February 2014
  • Implementation completion for the CL&D Policy: August 2017
  • Implementation completion for the Transition Policy: November 2020


ICANN specifies Registration Data Directory Service (RDDS) requirements through the Registry Agreement (RA) and the Registrar Accreditation Agreement (RAA). Registries meet their obligations using different service models, which are commonly referred to as "thin" and "thick" RDDS registries. This distinction is based on how two distinct sets of RDDS data are managed. "Thin" data is associated with the domain name, and "thick" data is associated with the registrant and contacts of the domain name.

  • Thin RDDS registries only maintain and provide the information associated with the domain name while registrars maintain and provide information associated with the registrant and contacts of the domain.
  • Thick RDDS registries maintain and provide both sets of data.
  • At the time of implementation of this Consensus Policy, only .COM, .NET and .JOBS were thin RDDS Registries

In line with section 7.2 of the Final Report [PDF, 1.2 MB], ICANN and the Thick WHOIS Implementation Review Team identified two outcomes for the Thick WHOIS Policy recommendations and agreed that their implementation could be split into two tracks:

  • Consistent Labeling and Display of WHOIS output for all gTLDs
  • Transition from thin to thick for .COM, .NET and .JOBS


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."