[plug] Preferred mail scanning system?

[Craig Ringer]

Hi folks

I'm in the process of upgrading our frightening hacked-up used-to-be-RH8
core server to Debian (live, thanks to the wonders of LVM2 and
debootstrap). This will be a slow, one-by-one service migration from the
main host to the debian chroot.

It's times like this that I remember why I like using Linux so much,
despite the problems - the fact that this is _possible_ is impossibly
cool. I migrating a live, running server so that effectively some
services run on one OS and one on another (though they share a kernel).

One of the services I'm going to migrate is mail. While our current
sendmail + SpamAssassin + ClamAV + MimeDefang setup works well, I'm not
overly happy with sendmail, nor the flexibility of MimeDefang or it's
monsterous memory use. I'm seeking a more flexible, lighter-weight
solution that:

	- can quarantine attachments with select file extensions
	- can quarantine attachments with select MIME types
	- doesn't send out "virus detected" mail
	- can pass messages on to a virus scanner then a spam filter
	- can quarantine messages _before_ passing to the virus scanner

The main names I hear coming up are amavisd-new, amavis-ng, mailscanner,
and of course MimeDefang. I was hoping folks here could offer some
opinions on experiences with the various ones they've used.

I'm looking to minimise the number of processes that must be started for
each mail delivery, so I'm really looking for something that talks LMTP
or plugs straight in to postfix. Final delivery to Cyrus will need to
happen over LTMP, so things that call out to procmail etc are no good to
me. Support for bypassing SpamAssassin for some senders would be a
bonus. Alternative, more efficient spam filter recommendations will also
be welcomed.

So ... any suggestions? Recommendations or horror stories?

Once I've decided on what I'm going to use and have it all set up I'll
let you folks know how it goes and how it all fits together.

--
Craig Ringer