Anti-spam methods (was: Re: [SLL] this list losing mail?)

[Kurt Buff]

On 7/27/07, Glenn Stone <technoshaman at liawol.org> wrote:
> On Fri, Jul 27, 2007 at 10:19:21AM -0700, Dan Wilder wrote:
> >On Thu, Jul 26, 2007 at 02:15:59PM -0500, Jeremy C. Reed wrote:
> >> Why does the linux-list mail server lose mails instead of bouncing? Or are
> >> they waiting for moderation?
> >
> >Spamfiled on a false positive on the way thru mxlogic.net, the MX
> >provider?
> >
> >Bouncing suspected spams has never been The Way To Go ... too much
> >collateral damage.
>
> If you can bounce it during the session, it's fine... but, definitely,
> bouncing after QUIT using the info available in the headers... bad juju.
>
> Which is one reason I haven't implemented system-wide  content
> filtering... I haven't figured out a good way to link Bayesian filtering
> into the SMTP session with Postfix (there's some milter stuff out there, but
> I haven't been able to get it to work right yet), and frankly I'd rather
> just eyeball the 10% or so that gets through and maybe do some Bayesian in
> procmail than try to maintain something system-wide...

Maia Mailguard (http://maiamailguard.com) might be what you're looking
for. I've just implemented it for our company (around 280 people in
the US/UK/AU), and it works very well indeed, though it might be more
overhead than what you want if you run a lightweight environment.

I've set it so that it quarantines all mail it thinks is spam, and it
can be set up to send a reminder message with a list of quarantined
mails, so that they can be reviewed and rescued by the end-user, along
with training of ham/spam.

It's pretty dang sweet.

Kurt