Syntax
- Letters A to Z (upper or lower case), digits 0 to 9 and the hyphen, with no other symbol.
- 255 characters at most in total, and 63 characters at most between two dots.
- Directly under .ht: at least one letter or digit (a.ht, 2.ht). Under an extension: at least one character (a.perso.ht).
- The dot separates sub-domains.
Forbidden
- A name that starts or ends with a hyphen.
- Accented characters: only the letter is kept (ë becomes e, ñ becomes n).
Terms that cannot be registered
Some terms are not allocated without suitable supporting documents, whatever the extension. The same goes for their synonyms or terms with the same root. This covers terms:
- related to public order or morality;
- related to how the Internet works;
- names of international organisations and of countries or territories in ISO 3166-1;
- related to historical and cultural heritage;
- the term Haiti, names of territorial authorities, towns and communes, national heritage buildings, names of professions, public and private companies and regulated titles.
A name made of a forbidden fundamental term can be taken back by the Consortium, without compensation but with a migration period and technical help if requested (article 21).