> There are some domain name registries that prohibit certain combinations of > characters in the name spaces they administer. The administrator of the .us > ccTLD, for example, prohibits use of the seven "dirty words" described by > the US FCC and George Carlin. While this isn't a restriction on the set of > valid characters, it _is_ a restriction on how they may be combined. I read > Erik's note to mean that registries may well prohibit certain Unicode code > points or combinations of code points for various policy or legal reasons, > and I'd agree with that assessment. > > Please correct me if my interpretation is wrong, Erik.
Our interpretation is correct. The "dirty words" was one type of restriction I had in the back of my head. Another type of restriction is the one I've vaguely heard about .se (and I don't know the actual policy rules so I'll be vague) which is that in order to be able to register a name in .se there has to be a corresponding (approximate?) legal company name being registered with Patent och Registreringsverket in Sweden. Just like the "dirty words" this is not a limitation in code points but a restriction that applies to the whole label. Another type of restriction might appear with the introduction of IDN is a "go slow" approach for allowing Uncode code points. For instance, a ccTLD registry might initially limit the IDNs that can be registered to use LDH plus additional code points used in the language(s) in that country. I don't see how any of these would cause interoperability problems, even though users might be inconvinienced by not being able to register arbitrary names in arbitrary TLDs. Erik
