Internationalized domain name
An internationalized domain name (IDN) is an Internet domain name that contains at least one label displayed in software applications, in whole or in part, in non-Latin script or alphabet[a] or in the Latin alphabet-based characters with diacritics or ligatures.[b] These writing systems are encoded by computers in multibyte Unicode. Internationalized domain names are stored in the Domain Name System (DNS) as ASCII strings using Punycode transcription.
"IDNA" redirects here. For the city, see Idna.
The DNS, which performs a lookup service to translate mostly user-friendly names into network addresses for locating Internet resources, is restricted in practice[c] to the use of ASCII characters, a practical limitation that initially set the standard for acceptable domain names. The internationalization of domain names is a technical solution to translate names written in language-native scripts into an ASCII text representation that is compatible with the DNS. Internationalized domain names can only be used with applications that are specifically designed for such use; they require no changes in the infrastructure of the Internet.
IDN was originally proposed in December 1987 by Martin Dürst[1][2] and implemented in 1990 by Tan Juay Kwang and Leong Kok Yong under the guidance of Tan Tin Wee. After much debate and many competing proposals, a system called Internationalizing Domain Names in Applications (IDNA)[3] was adopted as a standard, and has been implemented in several top-level domains.
In IDNA, the term internationalized domain name means specifically any domain name consisting only of labels to which the IDNA ToASCII algorithm (see below) can be successfully applied. In March 2008, the IETF formed a new IDN working group to update[4] the current IDNA protocol. In April 2008, UN-ESCWA together with the Public Interest Registry (PIR) and Afilias launched the Arabic Script in IDNs Working Group (ASIWG), which comprised experts in DNS, ccTLD operators, business, academia, as well as members of regional and international organizations. Operated by Afilias's Ram Mohan, ASIWG aims to develop a unified IDN table for the Arabic script, and is an example of community collaboration that helps local and regional experts engage in global policy development, as well as technical standardization.[5]
In October 2009, the Internet Corporation for Assigned Names and Numbers (ICANN) approved the creation of internationalized country code top-level domains (IDN ccTLDs) in the Internet that use the IDNA standard for native language scripts.[6][7] In May 2010, the first IDN ccTLDs were installed in the DNS root zone.[8]
Top-level domain implementation[edit]
In 2009, ICANN decided to implement a new class of top-level domains, assignable to countries and independent regions, similar to the rules for country code top-level domains. However, the domain names may be any desirable string of characters, symbols, or glyphs in the language-specific, non-Latin alphabet or script of the applicant's language, within certain guidelines to assure sufficient visual uniqueness.
The process of installing IDN country code domains began with a long period of testing in a set of subdomains in the test top-level domain. Eleven domains used language-native scripts or alphabets, such as "δοκιμή",[19] meaning test in Greek.
These efforts culminated in the creation of the first internationalized country code top-level domains (IDN ccTLDs) for production use in 2010.
In the Domain Name System, these domains use an ASCII representation consisting of the prefix "xn--" followed by the Punycode translation of the Unicode representation of the language-specific alphabet or script glyphs. For example, the Cyrillic name of Russia's IDN ccTLD is "рф". In Punycode representation, this is "p1ai", and its DNS name is "xn--p1ai".
Non-IDNA or non-ICANN registries that support non-ASCII domain names[edit]
Other registries support non-ASCII domain names. The company ThaiURL.com in Thailand supports ".com" registrations via its own IDN encoding, ThaiURL. However, since most modern browsers only recognize IDNA/Punycode IDNs, ThaiURL-encoded domains must be typed in or linked to in their encoded form, and they will be displayed thus in the address bar. This limits their usefulness; however, they are still valid and universally accessible domains.
Several registries support Punycode emoji characters as emoji domains.
Top-level domains accepting IDN registration[edit]
Many top-level domains have started to accept internationalized domain name registrations at the second or lower levels. Afilias (.INFO) offered the first gTLD IDN second-level registrations in 2004 in the German language.[20]
DotAsia, the registrar for the TLD Asia, conducted a 70-day sunrise period starting May 11, 2011 for second-level domain registrations in the Chinese, Japanese and Korean scripts.[21]