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New Report Presents Syntax and Operability Accuracy of WHOIS Data in gTLDs

LOS ANGELES – 19 December 2017 – Today, the Internet Corporation for Assigned Names and Numbers (ICANN) published the WHOIS Accuracy Reporting System (ARS) Phase 2 Cycle 5 Report. This is a follow-up to previous ARS Reports which have been published semi-annually since December 2015.

Read the Report.

The report explores both the syntax and operability accuracy of WHOIS records in generic top-level domains (gTLDs) as compared to the requirements of the 2009 and 2013 Registrar Accreditation Agreements (RAAs). It also examines the leading types of nonconformance, trends, and comparisons of WHOIS accuracy across gTLD types, ICANN regions, and RAA versions.

The ICANN org 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 were provided for the population of domains in gTLDs as a whole, as well as for several subgroups of interest.

Key Findings

The analysis found that:

  • Nearly all WHOIS records contain information that can be used to establish immediate contact: In 98 percent of records, at least one email or phone number meets all operability requirements of the 2009 RAA.
  • Approximately 94 percent of email addresses, 67 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 Three Accurate
All Three Contacts (Registrant, Technical, Administrative) Accurate 93.8% ± 0.4% 66.9% ± 0.8% 98.4% ± 0.3% 63.4% ± 0.9%
  • In terms of syntax accuracy, approximately 99 percent of email addresses, 90 percent of telephone numbers, and 89 percent of postal addresses were found to meet all the requirements of the 2009 RAA (see Table 2 below for more information).

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

  Email Telephone Postal Address All Three Accurate
All Three Contacts (Registrant, Technical, Administrative) Accurate 99.6% ± 0.1% 90.2% ± 0.5% 88.9% ± 0.6% 81.5% ± 0.8%

The report also shows a breakdown of accuracy rates by ICANN region (see Figure 1 below for more information).

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

Overall gTLD Syntax and Operability Accuracy by ICANN Region

Next Steps

Results included in the report 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. In response to ICANN community requests, the ICANN org now publishes additional metrics on the WHOIS ARS Contractual Compliance Metrics page here.

The ICANN org will begin work on the next WHOIS ARS report in January 2018, with a targeted publication date of June 2018.

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About ICANN

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 – into your computer or other device. That address must 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 with a community of participants from all over the world.


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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""icann.org"" is not an IDN."