A trivia question about domain names.

[Mark_Andrews at isc.org]

> 
> Once upon a time, RFC 1035 made domain names like:
> 
> 	beverly-hills.90210.com
> 
> illegal, because it disallowed domain name components that contained
> nothing but digit characters.
> 
> Somewhere along the line, that seems to have gotten changed, and now,
> domain name components can consist entirely of digit sequences.
> 
> Can anyone help me out and tell me which RFC, specifically, amended
> RFC 1035 so as to allow this?
> 
> 
	It was never illegal according to RFC 1035.

	Hostnames and mailnames (a subset of domainnames) are
	specified by RFC 952 & RFC 821 as modified by RFC 1123.
	Hostnames are not allowed to be all digits as it introduces
	confusion w.r.t. literal addresses.  This is enforced by
	not allocating all digit TLDs.

	Mark
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org