On Tue, 27 Jan 2009, Paul Smith wrote:
S: 220-main.remotedns.co.uk ESMTP Exim 4.63 #1 Mon, 26 Jan 2009 18:25:48 +0000
S: 220-We do not authorize the use of this system to transport unsolicited,
S: 220 and/or bulk e-mail.
C: EHLO vpop3.company.co.uk
S: 250-main.remotedns.co.uk Hello vpop3.company.co.uk [IP address]
S: 250-SIZE 52428800
S: 250-AUTH PLAIN LOGIN
S: 250 HELP
S: 220 TLS go ahead
C: MAIL FROM:<user(_at_)company(_dot_)co(_dot_)uk>
S: 550 HELO required before MAIL
(It happens with a few domains, all of which seem to be using Exim (4.63
This is a common but (obviously) non-standard anti-spam check. Practically
the only software that doesn't issue HELO or EHLO is malware so the check
has a negligible false positive rate. (Malware doesn't use TLS either, so
your bug is triggering a slightly over-broad check.)
It certainly looks as if it has forgotten the fact of the EHLO command
once the STARTTLS has happened.
As it is required to do.
<fanf(_at_)exim(_dot_)org> <dot(_at_)dotat(_dot_)at> http://dotat.at/