Skip to main content

Welcome to the new ICANN.org! Learn more, and send us your feedback. Dismiss

Discover ICANN

We bring together individuals, industry, non-commercial and government representatives to discuss, debate and develop policies about the technical coordination of the Internet's Domain Name System.

Get Started

News and Announcements

Apply Now for Key ICANN Leadership Positions

NomCom Announcement - Apply Now! 9 Leadership Roles Available

ICANN’s Nominating Committee is now accepting applications for leadership positions. Click the link above to learn about the 9 positions currently available and how to apply.

Five-Year Operating Plan

Strategy Chart with symbols and circles & text Five_Year Operating Plan

ICANN has introduced the addition of the Five-Year Operating Plan to its planning process, and is seeking public comment on the ICANN Draft Five-Year Operating Plan Version 1. Click above to learn more.

View all
Home groups
ICANN Groups

We depend on the support of many different types of groups and sub-structures: Advisory Commitees, Supporting Organizations, standingcommittees, working groups, review teams, task forces, and more.

Explore all Groups

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