A configuration was introduced ( from the holy powers ) which happens
to cause our server to backskatter and I am trying to fix the problem on
our end ASAP.
1. We relay to an offsite mail server for a few of our users (
contracted mail hosting )
2. This is M$exchange, and they have rules which reject mail that we
forward causing us to possibly backskatter. argh!
EX:
<r...@theholycat.com>: Sender address rejected: Domain not found (in
reply to RCPT TO command))
So I tried to use HELO checks and sender restrictions which works for
some but still lets many go through.
Using:
smtpd_sender_restrictions =
hash:/etc/postfix/access,permit_mynetworks,reject_unknown_sender_domain
Since reject_unknown_sender_domain finds a valid MX, this gets through.
So I am interested to know which settings I can implement that will
block these without forwarding since the MSexchange server seems to have
rules to catch them.
Also it appears that some of these connections don't use helo and it
this is important information to help with this, I will provide those.
Can anyone offer suggestions?
Thanks,
Randy Ramsdell
