Tue, Jun 15, 2004 at 15:06:15, DavidB wrote about "FW: [Exim] AOL - SPF - and EXIM":
> Only if you accept the HELO command in the first place, It says nothing
> about rejecting the HELO command because of verification failures.
> Please note that both the 2821 "Standards Track", and the official
> 1123 specificatons only say that the server must not refuse to accept
> a message if verificaition fails, neither say that the connection
> can not be terminated, nor do either say that the HELO/EHLO
> command must be considered acceptable when verification fails.
More detailed, it prohibits only one kind of rejection policy: correspondence
of $sender_helo_name and $sender_host_address. But this says nothing for
another kind of checks.
We don't accept bare IP addresses (in standard four-octet text form)
and this gives noticeable percent of rejections of spamming hosts.
Another group of checks gives formal and quick check for undoubtedly
invalid helo name (one that is invalid regardless of sender host multihoming,
multiple mail domains, etc.)
> <RFC 2821 "Standards Track">
> 4.1.4 Order of Commands
> If the EHLO command is not acceptable to the SMTP server, 501, 500,
> or 502 failure replies MUST be returned as appropriate. The SMTP
> server MUST stay in the same state after transmitting these replies
> that it was in before the EHLO was received.
Whether does this prohibit connection termination on inacceptable HELO/EHLO?
-netch-
