From woeber@cc.univie.ac.at Fri Oct 10 13:51:53 1997

Thanks to all who answered me. I am still confused, because the RFCs seem to be somewhat in contradiction with each other. The RFC1912 says: (Labels were initially restricted in [RFC 1035] to start with a letter, and some older hosts still reportedly have problems with the relaxation in [RFC 1123].) Note there are some Internet hostnames which violate this rule (411.org, 1776.com). On the other hand RFC1123 says: If a dotted-decimal number can be entered without such identifying delimiters, then a full syntactic check must be made, because a segment of a host domain name is now allowed to begin with a digit and could legally be entirely numeric (see Section 6.1.2.4). However, a valid host name can never have the dotted-decimal form #.#.#.#, since at least the highest-level component label will be alphabetic. This is in my view in contradiction with the last sentence quoted by me from RFC1912... [ More than that, RFC2181, which obsolates RFC1123, basically says that the DNS should be able to handle any binary string as a domain name (with the length limitations that apply). However, it emphasizes that the applications may impose restrictions on this... I am curious when will *.com be registered? :)) ] Janos