IDNA (Internationalizing Domain Names in Applications) is an Internet standard, in order to illustrate Domains, which non ASCII - letters contain, as valid ASCII stringers in the Domain Name System. One calls such Domainnamen IDN (Internationalized Domain Name), in the German linguistic area triviallyalso Umlautdomain.

University code - Domains are converted by means of the procedures Nameprep and Punycode to ASCII stringers, which as ACE - stringer (A SCII C ompatible E ncoding) to be designated. The transformation takes place with the Client (z. B. the Browser or Mailprogramm), so that the servers - infrastructure does not changewill must. Instead of the university code stringers the user in the Client can enter also directly the ACE stringers. So also Clients without IDN ability with international Domains can work, if the user knows the ACE stringer. Since this is however pedantic, it is recommended only if the software not IDN suitedis.

In principle all university code characters are permissible in IDNs. “Ss” as identical to “ss” one defined and with the normalization into ss one converts, so that for example “Pleisse” is identical with “Pleisse”. Each assignment place for Domains regulates separately, which indications it of oftheir assigned (Sub -) Domains permits. Since that 1. March 2004 know beside the 37 common indications (26 letters of latin of alphabet, 10 numbers and the minus sign) of German (.de) Second level Domains 92 and of Swiss (.ch) and of Liechtenstein (.li) Domains 31further indications to be used. Since that 31. 34 further indications are permitted March to 2004 for Austrian Domains (.at). Afilias, responsibly for .info - Domains, permits only the indications A, o and u.

Table of contents

processing of the university code stringer

first a Unicode Domain by Nameprep one normalizes, i.e. capital letters are converted to small letters and as equivalent defined indications into the standard format in the ASCII-Code (like that ss too ss equivalent is, it becomes thus from road road).

In the connectionto the normalization by means of Punycode the non--ASCII letters are removed from the name and added at the end of the name an ASCII stringer derived from in which the position and kind of the university code character are coded. In order to differentiate a IDN from a ASCII Domainnamen to, the Punycode stringer begins with thatplaced in front Prefix xn--.

character sets

.de Domains

à á â ã A å ā ă ą æ ç ć ĉ ċ č ď đ è é ê ë ē ĕ ė ę ě ŋ ð ĝ ğ ġ ģ ĥ ħ ì íî ï ĩ ī ĭ į ı ĵ ķ ĸ ĺ ļ ľ ł ñ ń ņ ň ò ó ô õ o ø ō ŏ ő œ ŕ ŗ ř ś ŝ ş š ţ ť ŧ þ ù ú û u ũ ūŭ ů ű ų ŵ ý ÿ ŷ ź ż ž

.com -, .net - Domains

à á â ã A å ā ă ą æ ç ć ĉ ċ č ď đ è é ê ë ē ĕ ė ę ě ŋ ð ĝ ğ ġ ģĥ ħ ì í î ï ĩ ī ĭ į ı ĵ ķ ĸ ĺ ļ ľ ł ñ ń ņ ň ò ó ô õ o ø ō ŏ ő œ ŕ ŗ ř ś ŝ ş š ţ ť ŧ þ ù úû u ũ ū ŭ ů ű ų ŵ ý ÿ ŷ ź ż ž

.info - Domains

A o u

.at Domains

à á â ã A å æ ç è é ê ë ð ì í î ï ñ ò ó ô õ o ø oeš þ ù ú û u ý ÿ ž

.ch Domains

à á â ã A å æ ç è é ê ë ð ì í î ï ñ ò ó ô õ o ø þ ù ú û u ý ÿ

.org - Domains

Ao u

example Domainnamen

  • www.dö →
  • www.kühe like ä →
  • www.ä →
  • www.aä →
  • www.aaä.de →
  • déjà.vu →
  • foo.âbcdé →

WHOIS - inquiry of the form WHOIS - an h -- - C ISO-8859-1 and/or. WHOIS - h -- - CUTF-8 on university code - supplies with to based systems with registered Domains and. A. the way of writing in Punycode.


around IDN to use to be able, must be able a Browser, which is also a Client, of it, that in the URL - line entered internationalDomainnamen (z. B. to convert with umlauts) into a ACE stringer.

List of IDN able Browser:

  • SeaMonkey starting from version 1.0, Mozilla starting from version 1.4, Netscape navigator starting from version 7.1
  • Firefox starting from version 0.8
  • Konqueror starting from KDE 3,2 with GNU IDN LIBRARY
  • Opera starting from version 7.11
  • safari starting from version 1.2(v125)
  • Microsoft Internet Explorer can be made due to the installation of the Plugins i-nav by VeriSign (see Web on the left of) IDN able starting from version 5.0. With the Internet Explorer 6 however occasionally incorrect operational sequence arise despite the Plugins. Microsoft announced however officially that the IE offVersion 7 IDNA will support. An alternative too i-nav offers the RFC-conformal Plugin Quero Toolbar (see Web on the left of), which is equipped with IDN Phishing protective mechanisms also.

Web on the left of


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