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Re: Strict RFC x821 Compliant: HELO/EHLO

2005-07-03 09:55:06

From: "Tony Finch" <dot(_at_)dotat(_dot_)at>

This would be an illegal syntax per the ABNF:

How do you know it's not a domain? Do you perform a DNS lookup?

See the discussion in RFC 1123 section 2.1: "a valid host name can never
have the dotted-decimal form #.#.#.#, since at least the highest-level
component label will be alphabetic."

Right, the TLD (the far right .#) can not be alphanumeric. (Probably it can
also be said it is known to not exist for registered top-level domains in

I do a inet_addr() conversion and if this comes back as INADDR_NONE (-1),
then you know its not a valid dotted-decimal format.

Hector Santos, Santronics Software, Inc.