[gentoo-user] disappearing mail

[Matt Harrison]

I've got an odd problem and I really can't work out what is causing it. I have two
gentoo mailservers under my control, one is working fine (it seems) but the other is
just not getting mail out. I'm not even sure if this will be delivered until I see it
come back through the list.

According to my logs, the mails are being accepted without issue by the receiving MX,
but that is the last that will be seen of them. It's not happening for every mail, but
a lot. Recipients can be on BT Internet, gmail, or other (apparently) unrelated
providers.

All outgoing mail from this server is DKIM signed, in plaintext only. I've checked and
the IP of the server doesn't seem to be on any blacklists. There is correct reverse
dns for the server as well. I've owned the IP for around 7-8 years now and there's
never been a problem like this.

I've been scratching my head over this for a while now but haven't made any progress,
in fact it seems to be getting worse. A few days ago I found a free service
(unfortunately forgotten the name now) which will recieve an email from you and reply
with a complete breakdown of apparent authenticity, signing, spam score etc etc. It
was absolutely perfect for my test.

Both servers are running the current stable postfix and amavisd/clamav/spamassassin.

It looks to my uneducated brain that servers are accepting my mail and then silently
dropping it without telling me why. Some of the intended recipients have checked their
various spam folders and such but nothing shows up there either.

If anyone can shed some light on this I would be incredibly grateful, I'm having to
send quotes out through the post at the moment just to be sure they arrive :(

Many thanks

Matt