ietf-smtp
[Top] [All Lists]

Re: Strict RFC x821 Compliant: HELO/EHLO

2005-07-03 10:12:31

On Sun, Jul 03, 2005, Tony Finch wrote:

helo 65.10.44.25

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."

Ok, let's try this again: The statement was:

"This would be an illegal syntax per the ABNF:"

This statement is wrong. The parameter is _syntactically_ valid (as
I pointed out before by quoting the grammar).  Maybe it would be
useful to change the syntax to reflect that "the highest-level
component label will be alphabetic.". As long as that isn't the
case, the command above is correct according to the grammar given
in RFC 2821 (that's why my software doesn't reject it in contrast
to the _syntactically_ invalid MAIL command that triggered this
HELO/EHLO discussion).