Re: [FWP] Recursion, anyone?

["Abigail" <abigail@foad.org>]

On Wed, Apr 11, 2001 at 11:17:45PM +0100, Ian Phillipps wrote:
> On Wed, 11 Apr 2001 at 17:46:46 -0300, Filipe Brandenburger wrote:
> 
> > I am now thinking about the rules for generating the names.
> > Anyone knows what they are? I know that numbers are allowed
> > at the beginning of a domain name, but I don't know if - is.
> > I also don't know if two -'s in a row (--) are allowed.
> 
> >From RFC 1034:
> 
> <domain> ::= <subdomain> | " "
> <subdomain> ::= <label> | <subdomain> "." <label>
> <label> ::= <letter> [ [ <ldh-str> ] <let-dig> ]
> <ldh-str> ::= <let-dig-hyp> | <let-dig-hyp> <ldh-str>
> <let-dig-hyp> ::= <let-dig> | "-"
> <let-dig> ::= <letter> | <digit>
> <letter> ::= any one of the 52 alphabetic characters A through Z in
>     upper case and a through z in lower case
> <digit> ::= any one of the ten digits 0 through 9
> 
> So, the answer that 'A--' is legal.

Eh, no. While the above grammar makes it legal to have two dashes in
a row, it's *not* legal for a label to end with a dash.

'A--A' is legal, 'A--' isn't.

> And www.f--k.com exists, and for sale...

I don't accept that as a proof that it is allowed by an RFC... ;-)



Abigail

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