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ICANN Calls for Full DNSSEC Deployment, Promotes Community Collaboration to Protect the Internet

LOS ANGELES – 21 February 2019 – The Internet Corporation for Assigned Names and Numbers (ICANN) believes that there is an ongoing and significant risk to key parts of the Domain Name System (DNS) infrastructure. In the context of increasing...

Cyrus Namazi Appointed to Senior Vice President of ICANN's Global Domains Division

LOS ANGELES – 21 February 2019 – The Internet Corporation for Assigned Names and Numbers (ICANN) today announced that Cyrus Namazi has been appointed to the newly created position of Senior Vice President of the Global Domains Division (GDD), and...

Proposal for Hebrew Script Root Zone Label Generation Rules

Open Date: 20 February 2019 Close Date: 18 April 2019 Originating Organization: Global Domains Division Categories/Tags: Top-Level Domains Brief Overview: The Hebrew...

Application Deadline Extended for ICANN and PTI Leadership Positions

LOS ANGELES – 19 February 2019 – The Internet Corporation for Assigned Names and Numbers (ICANN) Nominating Committee (NomCom) has extended its application deadline for ICANN and PTI leadership positions. The new deadline is Friday, 22 March 2019...




Why You Should Join the ICANN Board

ICANN Board Members speak about serving on the ICANN Board.


SSAC Chair Rod Rasmussen on IDN Homographic Attacks

In an interview with ICANN’s Andrew McConachie, Security and Stability Advisory Committee (SSAC) Chair Rod Rasmussen discusses the use of Internationalized Domain Name (IDN) homographic attacks....

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EPDP Update

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Blog Posts

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Technical Study Group Advances Draft Model

Chair’s Blog: Wrapping up the Los Angeles Workshop

Second Security, Stability, and Resiliency (SSR2) Review Team Update


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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."