>I am looking into integrating a spam filter with Exim. I was
>mainly looking at Spam Assassin,
Existing techniques for this are usually combined with virus
scanning. I know of the following that can be used with exim. All
combine virus scanning with spam detection. I suspect (3) may be
the only approach that can just run spam detection.
(1) amavisd-new, available from:
http://www.ijs.si/software/amavisd/
(The amavis project is based at:
http://www.amavis.org/
and is just concerned with virus detection.)
(2) MailScanner from:
http://www.sng.ecs.soton.ac.uk/mailscanner/
(3) Tom Kistner's exiscan from:
http://duncanthrax.net/exiscan/
Of the above I expect that MailScanner will make the most efficient
use of CPU power etc.
Tom Kistner's exiscan uses exim4's local_scan facility and can
reject suspect email during the SMTP transacation. I personally
like this approach; it gets rid of suspect mail at the earliest
opportunity. Note it rejects the suspect email while the SMTP
connection is still open. Thus the sending MTA is responsible for
generating the error message. The receiving MTA won't have to care
if the envelope sender is forged -- this happens a lot with viruses
sent by email -- and so run the risk of sending a virus warning
message to the wrong person.
> but a colleague gave me a magazine article which mentioned
>Bogofilter (http://www.tuxedo.org/~esr/bogofilter/). I was
>wondering if anybody on the list has used or tried this software
>with Exim. If so, do you know how well it compares with others,
Bogofilter is bayesian mail filtering software. For further
information you might like to look at Paul Graham's article:
http://www.paulgraham.com/spam.html
Other bayesian mail filtering software can be found at:
http://sourceforge.net/projects/bmf
I've certainly not used bmf. However there is a port of this
software in the latest OpenBSD ports tree. And I've seen comments
from one OpenBSD user that he's happy with using bmf. As usual,
your mileage may vary...
