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Frequently Asked Questions

What can we do for you?

Information on IDNs

When will my ß-domain be ready for use?

All ß-domains can be used immediately after registration. They are covered by the output of the DENIC information services in realtime.

Please note our information on how some web browsers treat domains containing the letter "ß".

Can I register an ß-domain with DENICdirect?

Yes, you may also register an ß-domain with DENICdirect.

Since November 2010 the letter "ß" is incorporated as a valid character in the Annex of the DENIC Domain Guidelines. Consequently, anybody can register ß-domains in accordance with the standard registration procedure.

How can I query an ß-domain?

Like all other domains, you can query ß-domains via DENIC's regular information services.

You can use the domain query service (web-whois) on DENIC's website or the command-line-based public-whois for this purpose.

I already hold a .de domain in which an umlaut has been replaced by the two-letter equivalent (along the lines of for mü Is DENIC going to g

No. There would no factual reason to do so either, since and mü are two completely different domains. It is just like, which has nothing to do with baü, or and pö, which are not the same either. Why then should the holder of be given any precedence over Germany’s myriad of other Müllers? Such a procedure would go against the clear principle that DENIC has established that a domain goes to whoever applies to register it first – i.e. first come, first served, with no exceptions.

In this context, we should like to remind you of the clear rule that it is domain applicants themselves who are responsible for ensuring that they do not infringe any rights of others and that they expressly confirm this in applying to register a domain. You’ll find more details about this in DENIC’s Domain Guidelines and in its Domain Terms and Conditions.

Which characters are permitted in .de domains?

Besides the ASCII characters (the 26 Latin letters, the ten numerals and the hyphen) you may use some other characters for IDNs under .de. These include the German umlauts ä, ö and ü as well as the letter eszett ("ß") and letters with accents and other diacritics. We have compiled a list with the new additional characters valid for IDNs under .de in a table for you.

You might wonder why these particular 93 characters have been chosen and not others. There are several reasons:

  • DENIC supports all characters included in the Unicode Latin-1 Supplement and Latin Extended-A blocks which are marked as "PROTOCOL VALID" in the RFC 5892 (The Unicode Code Points and Internationalized Domain Names for Applications).
  • DENIC is an open registry free from any form of discrimination. In Germany, there is no meaningful way of drawing a line between the various character sets, since the written German language now includes characters that originated in the languages of the northern, southern and eastern parts of Europe. The sensible and appropriate solution for us therefore seemed to be to adopt two blocks that cover the necessary European character set for those languages that are based on the Latin alphabet, including some additional characters.
  • The most frequently used new characters of these character sets can be entered via standard German keyboards without requiring any additional equipment or outlay.

I want to see what characters will be possible in IDNs. Is there anywhere I can look them up?

Yes. Just call the table DENIC has compiled for you. It contains a list of all the admissible characters, plus their corresponding numbers (in both decimal and hexadecimal) in the Unicode table, along with their official designations in both English and German. This table can also be used by your computer’s copy function. Simply mark a letter in the table and then paste it either to your browser or DENIC's whois search.

What are the rules for the minimum and maximum lengths of character strings in IDN domains?

A .de domain must consist of at least one character, but its maximum length must not exceed 63 characters. In the case of IDNs, the question immediately arises as to whether these length constraints refer to the IDN itself (such as straß or its transposition as an ASCII character string (

For technical reasons, the maximum length of 63 characters applies to the ASCII character string, whereas the minimum length of three characters applies to the IDN.

Are IDNs permitted as host names for name servers and NSentries?

No. These entries are loaded directly into the name server and are not transposed first. The situation for host names for name servers and NS entries remains precisely what it has been so far: the only permitted designations are those that are comprised solely of the basic ASCII character set. It is thus possible to enter the punycode value (such as as the host name in the name-server entries but not the corresponding IDN (such as dns.straß

This arrangement has one big advantage in that hosts with Japanese, Chinese, Cyrillic, etc. names can also act as name servers too and there are no limitations to a particular character set. It is true that such host names cannot be registered under .de, but other registries are free to choose what letters and other characters they want to permit and, of course, their decisions are guided by the needs of the internet users they cater for.

What is Unicode?

Computers can only work with numbers. So letters of the alphabet and other characters have to be assigned to numbers before computers can process and store them. Before Unicode was developed there used to be hundreds of different coding systems, and not one of them was complete. Even just concentrating on one language (such as German) there was not a single system that really contained all the letters of the alphabet, punctuation marks and technical symbols in common use. The situation was rendered even more unsatisfactory in that it was not possible to use these various coding system side-by-side at the same time, since the various numbers were assigned to different characters. All this changed with the advent of Unicode, which now ensures unique assignments of characters to numbers, no matter what hardware and software is used. Texts that use Unicode can be exchanged throughout the world without problems or loss of information.

The original definition of Unicode and its further development is in the hands of the Unicode-Consortium, a non-profit body, whose purpose is to normalize and standardize the representation of text data in the computer field. The consortium's members include many companies and institutions from the IT sector.

What does "punycode" mean?

Punycode is a rule that describes how Unicode characters are assigned uniquely to ASCII character strings. You will find a technical definition of this rule in RFC3492 (Punycode: A Bootstring Encoding of Unicode for Internationalized Domain Names in Applications).

In an extremely simplified form, the following is what happens in this transposition:

The previously normalized IDN has the prefix "xn--" placed in front of it. All non-ASCII characters are taken out. The punycode algorithm determines what these characters were and where they stood and adds this coded information to the end of the string that is left. To give an example: "zää" is encoded as "".

Why is an "ß"-domain (such as "straß") not always resolved properly?

If a domain with the letter "ß" in its name is resolved correctly, for instance by a web browser, depends on the fact if the web browser that is used supports the new IDN standard that has come into effect in August 2010.

As long as there are some vendors who have not yet updated their browsers and/or users who apply older browser versions which still automatically convert the "ß" into "ss", failures may occur. Such browsers will resolve the entry "straß" to the domain "".

We have set up a list of IDN capable software for you.