Internationalized domain name
As internationalized domain names (English internationalized domain names, IDN), colloquially umlaut domain or special characters domain, domain names are called, contain the special characters, diacritics or letters from other alphabets other than the Latin alphabet. Such characters Name System were originally not foreseen in the domain and have been made possible by the Internet standard retrospectively Internationalizing Domain Names in Applications ( IDNA ).
Basically almost all Unicode characters are allowed in IDNs. Each award for domains regulates individually but which characters it allows for domain registrations.
- 2.1 Generic top -level domains 2.1.1. Com and. Net
- 2.1.2. Info
- 2.1.3. Org
- 2.2.2. Ch and. Li
- 2.2.3. De
Operation
Unicode domain names to ASCII compatible encodings (English ASCII -compatible encoding; ACE) converted. The conversion is done on the client (eg the browser or mail program ) so that the server infrastructure need not be adjusted. Instead of Unicode strings, the user can also directly enter the ACE string in the client. So even clients without IDN ability to work with internationalized domain names, provided that the user knows the ACE string. However, this is cumbersome, since one of the Unicode domain names can not be read easily as a user of an ACE string.
In the original method IDNA2003 (RFC 3490) the domain names were first normalized by the Nameprep process. Normalization was to replace all uppercase letters in lowercase and exchange equivalent characters. For example, "ß" was considered equivalent to "ss " is specified, so that the domain name "street" and " road " were identical. With the new version IDNA2008, which is partially become known as IDNAbis and was developed from 2008 to 2010 (RFC 5890, RFC 5891, RFC 5892, RFC 5893, RFC 5894 ), normalization is no longer part of IDNA, but is in the responsibility of the user interface. Although IDNA2008 writes no normalization before more, but recommends a general algorithm, in which the conversion from upper case to lower case and a few other rules are also provided. In. De it's since November 16, 2010 ( for holders of a domain with "ss" before it) possible to register separate domains with "ß".
Following the normalization of the non-ASCII characters are removed from the name and added to the end of the name, any derivative ASCII string, in which the position and type of Unicode character is encoded using Punycode. To distinguish an IDN of an ASCII domain names, the Punycode string starts with the xn - prefix. The unusual string xn - was chosen because it practically does not occur in real words or proper names and conflicts with ASCII domains are therefore extremely unlikely.
Incompatibilities of IDNA2003 and IDNA2008
The Unicode Technical Standard 46 describes measures that the incompatibilities between IDNA2003 and IDNA2008 to be minimized in practice to facilitate the transition from IDNA2003 on IDNA2008. But even three years after launch is the browser support for IDNA2008 still poor ( see also section support in the browser): Since IDNA2003 "ß" to " ss" mandatory converts, the new " beta " domains therefore are often not callable or refer to the previous " ss" domains. As long as "ß " domain and "ss" domain belonging to the same range, the user usually does not know anything; however, if the "ß " domain and "ss" domain belonging to different offers, sometimes this leads to confusion.
Moreover allowed IDNA2008 about 8,000 Unicode characters no longer that were still valid after IDNA2003 components of domain names so that previously valid domain names that contain these characters on IDNA2008 be invalid when upgrading from IDNA2003.
Example domains
Dömäin.example → xn - dmin - moa0i.example äaaa.example → xn - aaa pla.example aäaa.example → xn - aaa qla.example aaäa.example → xn - aaa rla.example aaaä.example → xn - aaa sla.example déjà.vu.example → xn - dj- kia8a.vu.example efraín.example → xn - Efran - 2sa.example ñandú.example → xn - and- 6ma2c.example foo.âbcdéf.example → foo.xn - BCDF 9na9b.example موقع وزارة -. الاتصالات مصر → xn -. 4gbrim.xn ---- ymcbaaajlc6dj7bxne2c.xn - wgbh1c - ☃ example → xn -. N3h.example ( allowed by IDNA2003, but prohibited by IDNA2008 ) fußball.example → xn - fuball - cta.example ( will fussball.example mandatory under IDNA2003, but not after IDNA2008 ) A Whois query of the form whois-h whois.denic.de --- C ISO -8859-1 example.com or whois-h --- C whois.denic.de UTF -8 example.com to Unicode - based systems provides for registered domains including the spelling in Punycode.
Fonts
Since May 2010, there are IDN top- level domains, and thus complete domains from non- Latin characters. For example, there is the top-level domain مصر, which is the Arabic word for Egypt ( Misr ). ; the website of the Egyptian Ministry of Communications and Information Technology is over the existing solely of Arabic character domain http:// موقع وزارة -. . الاتصالات مصر / reach. The domain name is to be read according to the Arabic from right to left.
The following top- level domains is listed for some, that non-ASCII characters are allowed in the IDN domains:
Generic top -level domains
. com and. net
. info
. org
Country-specific top- level domains
. ch and. li
. de
The proportion of IDNs to all registered domains under. De is around four percent.
Support in the browser
Support for internationalized domain names is common in current browsers, at least according IDNA2003. On the other hand is supported IDNA2008 in 2013 from almost any browser.
Some IDNA2003 -enabled browser:
- Chrome
- Firefox 0.8
- Konqueror from KDE 3.2 with GNU IDN Library
- Internet Explorer version 7.0
- Mozilla Application Suite version 1.4
- Netscape Navigator version 7.1
- Opera version 7.11 or
- Safari version 1.2 ( v125 )
- SeaMonkey version 1.0