[idn] Name forms in the requirements doc

[Paul Hoffman / IMC <phoffman@imc.org>]

The last paragraph of section 1.2 of the requirements document says:

>The form specified for most protocols using the DNS is a limited form of
>the master file format domain name. This limited form is defined in
>[RFC1034] Section 3.5 and [RFC1123]. In most implementations of
>applications today, domain names in the Internet have been limited to
>the much more restricted forms used, e.g., in email.   Those names are
>limited to the ASCII upper and lower-case characters (interpreted in a
>case-independent fashion), the digits, and the hyphen, with the further
>restrictions that a name may not consist entirely of digits and that a
>hyphen cannot occur at the beginning or end of a component or following
>another hyphen.

Where did the restrictions of "may not consist entirely of digits" 
and "a hyphen cannot occur...following another hyphen" come from? I 
cannot find those in 1034 or 1123.

--Paul Hoffman, Director
--Internet Mail Consortium