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Syntax and Operability Accuracy of WHOIS Data in gTLDs Presented in Second Cycle of Phase 2 of the Accuracy Reporting System

ICANN today published the Phase 2 Cycle 2 report of the WHOIS Accuracy Reporting System (ARS), which acts as a follow-on to the Phase 2 Cycle 1 report [PDF, 1.7 MB] published in December 2015. During Cycle 2, ICANN again measured both the syntax and operability accuracy of WHOIS records in gTLDs as compared to the requirements of the 2009 and 2013 Registrar Accreditation Agreements (RAAs). The Cycle 2 report discusses the leading types of nonconformances, trends and comparisons of WHOIS accuracy across ICANN regions, RAA versions and gTLD types.

Read the Phase 2 Report [PDF, 2.6 MB].

ICANN developed accuracy tests to answer questions about the syntax (format and content) and operability (e.g., does an email sent to the email address provided in the WHOIS record go through?) of a sample of WHOIS records. Then, using statistical methods, syntax and operability accuracy estimates with a 95 percent confidence interval were provided for the population of domains in gTLDs as a whole, as well as for several subgroups of interest. The analysis found that 99% percent of records had at least one method of contact that met all syntax and operability requirements of the 2009 RAA, which implies that nearly all records contain information that can be used to establish contact.

In terms of operability accuracy, the Cycle 2 report shows that approximately 91 percent of email addresses, 76 percent of telephone numbers and 98 percent of postal addresses were operable. See Table 1 below for more information.

Table 1: Overall gTLD Operability Accuracy by Contact Mode (95 percent confidence interval)

  Email Telephone Postal Address All 3 Accurate
All 3 Contacts (Registrant, Technical, Administrative) Accurate 91.4% ± 0.5% 76.0% ± 0.8% 97.7% ± 0.3% 70.2% ± 0.8%

In terms of syntax accuracy, the Cycle 2 report shows that approximately 99 percent of email addresses, 85 percent of telephone numbers and 77 percent of postal addresses were found to meet all the requirements of the 2009 RAA. Table 2 below provides more information.

Table 2: Overall gTLD Syntax Accuracy to 2009 RAA Requirements by Contact Mode (95 percent confidence interval)

  Email Telephone Postal Address All 3 Accurate
All 3 Contacts (Registrant, Technical, Administrative) Accurate 99.2% ± 0.2% 85.3% ± 0.6% 77.3% ± 0.7% 67.2% ± 0.8%

Finally, the Cycle 2 report shows how the accuracy rates break down by ICANN region. Figure 1 below provides more information.

Figure 1: Overall gTLD Syntax and Operability Accuracy by ICANN Region

Figure 1: Overall gTLD Syntax and Operability Accuracy by ICANN Region

Next Steps for Cycle 2

ICANN will host a webinar on 16 June 2016 at 14:30 UTC to provide insight into the methodology and findings of the WHOIS ARS Cycle 2 report.

View webinar details.

The results of Cycle 2 have been provided to ICANN's Contractual Compliance team, which will assess the types of errors found and follow up with registrars on potentially inaccurate records. If WHOIS inaccuracy and/or format complaints are created from the WHOIS ARS data, ICANN Contractual Compliance will issue tickets in accordance with the Contractual Compliance Approach and Process [PDF, 292 KB]. Compliance provides updates on a quarterly basis, which include updates on WHOIS ARS tickets and can be found here.

Next Steps for the WHOIS ARS

As Phase 2 is completed cyclically every six months, ICANN will begin work on Cycle 3 in July 2016. Testing is expected to be complete by October 2016 and a report on Phase 2 Cycle 3 is targeted for early December 2016. Cycle 4 will then begin in January 2017.


ICANN reviews the WHOIS Program every three years as part of its Affirmation of Commitments (AoC). On 8 November 2012, the ICANN board approved a series of improvements to the manner in which ICANN carries out its oversight of the WHOIS Program based on recommendations made by the 2012 WHOIS Review Team. As part of these improvements, ICANN committed to proactively identifying potentially inaccurate gTLD WHOIS contact data and forwarding these records to registrars for investigation and follow-up. To accomplish these tasks, ICANN initiated the development of the WHOIS Accuracy Reporting System. Throughout the development ICANN has consulted and collaborated with the community.

The ARS is intended to lead to improvements over time in the accuracy of WHOIS data, which will be examined in subsequent ARS reports.


ICANN's mission is to help ensure a stable, secure and unified global Internet. To reach another person on the Internet, you have to type an address into your computer - a name or a number. That address has to be unique so computers know where to find each other. ICANN helps coordinate and support these unique identifiers across the world. ICANN was formed in 1998 as a not-for-profit public-benefit corporation and a community with participants from all over the world. ICANN and its community help keep the Internet secure, stable and interoperable. It also promotes competition and develops policy for the top-level of the Internet's naming system and facilitates the use of other unique Internet identifiers. For more information please visit:

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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."