[Lias] Re: Spam filters

[Craig Ringer]

On Tue, 2005-04-26 at 13:40 +1000, Paul Gear wrote:
> John Glennie wrote:
> > Hi Paul
> >  
> > Do you know if there is a Linux 'free' spam filter??
> >  
> > We are getting increasing amounts of spam and I would like to test
> > something before spending money on Windows based commercial solutions.
> 
> I highly recommend the combination of postfix, amavisd-new,
> spamassassin, and clamav.

I can second that. I've had very good results with the virus filtering
side. Spam filtering has been nowhere near as good - I bounce a lot
outright, but after that it's been ~50% hits. My spam filters are
*extremely* conservative and entirely omit keyword filtering, however -
operating a newspaper's network, one can't afford to block anything on
keywords.

It should be easy to knock out about 90% using a few regexp matches in
postfix alone, if you can afford to do "dumb" content filtering.

Load hasn't been a significant issue, though the server only processes a
couple of thousand messages a day (and it's a *big* server). Most
suspect mail is rejected by the initial mail gateway anyway - without
that I expect I'd be seeing ~10 times the current traffic levels, almost
all spam.

-- 
Craig Ringer