Re: [gentoo-server] SMTP Woes

[Wendall Cada <wendallc@83864.com>]

On Fri, 30 Nov 2007 02:00:20 -0500
Randy Barlow <randy@electronsweatshop.com> wrote:

> I am getting a huge number of connections to my mail server (postfix)
> compared to usual.  I've seen as many as 50 connections open at one
> time.  The logs show that the connections are from several computers
> of varying IPs, and they are all trying to send mail to random
> mailboxes on my domain.  It's very annoying, and I have noticed that
> inbound mail seems to be lagging by several hours.  Is there
> something similar to denyhosts for spammers?  Any other suggestions?
> 

There are a variety of reasons this many incoming connections can be
generated. No amount of blacklist/greylist filtering will do anything
to prevent them from happening. If you block them at the firewall, they
will just keep retrying and you'll end up making the problem worse. You
need to give a 550 to every incoming connection, regardless. It sounds
like you are using a DB on the backend for user lookups. If so, there
are important optimizations that need to be made to make this issue a
moot point.

First, it would be nice to know what MTA you are using, and secondly if
you are using a database backend for lookups. With that information, I
could give some specific answers on how to better optimize your setup
for dealing with the garbage.

Wendall
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