On Mon, Sep 05, 2011 at 04:48:31PM +0100, Matt Harrison wrote:
> 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 :(

Well that one got through which is nice, and I just noticed that my servers time was
just over an hour off, even though ntp-client was running. Only noticed this thanks to
the threading in this list. My every day stuff doesn't get threaded (or posted back to
me) so I hadn't seen it before.

I've corrected the time and sent a couple of tests to previously not working addresses
and I'll see what happens.

Just a thought though, if for example, BT Internet was reject mail based on my clock
being so wrong, they'd do it for every customer...and they haven't. I don't know, I'm
out of ideas and pretty desperate now.

Thanks

Matt