Hi, long story short, there is a bug in recent Seamonkey builds that emits an empty hostname in EHLO on Windows platforms with IPv6, see https://bugzilla.mozilla.org/show_bug.cgi?id=858540
This is extremely hard to debug when a user complains, because while Postfix rejects it with 501 EHLO 501 Syntax: EHLO hostname it does not log anything at all in the default loglevel Dec 11 15:24:32 lxmhs65 postfix-mailout/smtpd[44180]: connect from lxbsc02.ipv6.lrz.de[2001:4ca0:0:f000:221:9bff:fe80:d1cd] Dec 11 15:24:53 lxmhs65 postfix-mailout/smtpd[44180]: disconnect from lxbsc02.ipv6.lrz.de[2001:4ca0:0:f000:221:9bff:fe80:d1cd] Increasing the loglevel for all clients just to be able to search for it when an incident comes in would be a bit excessive. I could also not find a way to disable that check. Questions: a) Would it be possible to get a log message when EHLO is rejected (or other syntax errors occur)? b) is there a way to log all SMTP I/O (minus STARTTLS exchange and DATA of course) commands in verbatim (what we get with debug_peer_level = 2, but that's already way too much as it also emits hundreds of debug lines for map lookups)? We're using postfix-2.10.1 Bernhard
