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Report a name collision

A name collision occurs when an attempt to resolve a name used in a private name space (e.g. under a non-delegated Top-Level Domain, or a short, unqualified name) results in a query to the public Domain Name System (DNS). When the administrative boundaries of private and public namespaces overlap, name resolution may yield unintended or harmful results.

Name collisions are not new. The introduction of any new Domain Name into the DNS, whether a generic TLD, country code TLD or Second-Level Domain name (SLD) creates the potential for name collision. A secure, stable and resilient Internet is ICANN's number one priority. Therefore, we've made a commitment to the Internet community to launch a substantial effort to mitigate and manage collision occurrence.

If your system is suffering demonstrably severe harm as a consequence of name collision, please fill in the form below to report the incident.

ICANN will initiate an emergency response for name collision reports only where there is a reasonable belief that the name collision presents a clear and present danger to human life.

The emergency response could include temporarily removing the effected SLD or the entire TLD from the DNS. ICANN will serve as the initial reporting point, and if necessary will coordinate with registry operators to ensure that the report is acted upon in an expedited manner. ICANN's contracted Registry Operators are required to act on requests from ICANN within 2 hours of receipt of the request from ICANN.

If you believe your name collision meets the criteria above (i.e. your system is suffering demonstrably severe harm as a consequence of name collision or you have a reasonable belief that the name collision presents a clear and present danger to human life), please use the form below to submit your report to ICANN.

After submitting the report, please review the Guide to Name Collision Identification and Mitigation for IT Professionals [PDF, 476 KB] for more information.

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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."