Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

Sendmail As Spam Filter

0 views
Skip to first unread message

Ken - Tech

unread,
Nov 11, 2003, 8:51:26 AM11/11/03
to

Somewhat of a newbie to Linux & Sendmail. What I would like to do is setup
a linux/sendmail box to act as a spam filter for e-mail coming into my
office . This box would either be a pop/smtp server for the office or
operate as an e-mail forwarder, filtering spam first, to an MS Exchange
server.

Any comments on filters built into sendmail and/or other filter add-ons for
linux/sendmail would be greatly appreciated.

Thank you - Ken


Alexander Dalloz

unread,
Nov 11, 2003, 10:39:12 AM11/11/03
to

I can recommend Mimedefang in conjunction with SpamAssassin. Milter-sender
works fine too for me. You will find many comments in this group's
archive. For a specific application please go to it's project page.

Alexander


--
Alexander Dalloz | Enger, Germany
PGP key valid: made 13.07.1999
PGP fingerprint: 2307 88FD 2D41 038E 7416 14CD E197 6E88 ED69 5653

Alicia

unread,
Nov 11, 2003, 1:14:39 PM11/11/03
to
The problem with content filtering, like Perl based SpamAssassin, is
the overhead for large domains, false positives, and they can be
tricky for non-local mailboxes (such as forwarding messages to another
mail server).

You should also consider using SpamHaus & SpamCop (abuse.net) RBL's
(Realtime BlackLists). On their own, they block over 90% of the
incoming spam to my sendmail server, and if you wish, you can also
combine them with content filters like SpamAssasin. So far, we
haven't has a false positive.

While on this topic, does any know of any other effective RBL's that
is worth adding to sendmail, and does not produce false postives?
What about a large database of known dialup & broadband ISP network
blocks, so that their virus infected computers don't relay spam?

Alicia.

PS. Below is an excert at the bottom of my sendmail.cf file showing
the portion that implements the spamhaus & spamcop RBL's.
Don't forget to put [TABS] between the left & right columns!

######################################################################
Scheck_mail
# DNS based IP address spam list sbl.spamhaus.org
R$* $: $&{client_addr}
R::ffff:$-.$-.$-.$- $: <?> $(host $4.$3.$2.$1.sbl.spamhaus.org. $:
OK $)
R$-.$-.$-.$- $: <?> $(host $4.$3.$2.$1.sbl.spamhaus.org. $:
OK $)
R<?>OK $: OKSOFAR
R<?>$+ $#error $@ 5.7.1 $: "Spam blocked see:
http://spamhaus.org/ and
http://www.abuse.net/sbl.phtml?IP="$&{client_addr}
# DNS based IP address spam list bl.spamcop.net
R$* $: $&{client_addr}
R::ffff:$-.$-.$-.$- $: <?> $(host $4.$3.$2.$1.bl.spamcop.net. $:
OK $)
R$-.$-.$-.$- $: <?> $(host $4.$3.$2.$1.bl.spamcop.net. $:
OK $)
R<?>OK $: OKSOFAR
R<?>$+ $#error $@ 5.7.1 $: "Spam blocked see:
http://spamcop.net/bl.shtml?"$&{client_addr}
######################################################################

0 new messages