[K12OSN] OT: just reduced spam by 95% with Free Software

[Vince Callaway]

On Sun, 2007-01-28 at 12:46 -0800, Huck wrote:
> where does 'postmaster' mail get sent? I'm inundated with spam from such.

Pretty common spam trick.

I have postmaster, abuse and root are sent to my mailbox.  I don't do a
catchall mailbox.

One simple thing that will greatly reduce spam is to use the realtime
blacklist that blocks mail from China and Korea.  About 90% of the spam
originates from there.

This is the listing from my blacklists file for qmail:
-r dnsbl.tqmcube.com -r dnsbl.sorbs.net -r sbl-xbl.spamhaus.org -r
bl.spamcop.net -r cbl.abuseat.org -r dnsbl-1.uceprotect.net -r
dnsbl-2.uceprotect.net -r dnsbl-3.uceprotect.net -r combined.njabl.org

tqmcube.com catches the bulk of the spammers.  That is why it is listed
first in my file.  This might be too many to check on a heavily loaded
mailserver.  If I were to limit myself it would be the first two in the
list.

Anything that gets through the blacklists gets checked with
spamassassin.  I use the rulesets from saupdates.openprotect.com and
check for updates nightly.

My server is also setup to do spf checking.

This mail project got started because spammers where using
totalsense.com in their return addresses.  Guess they took a liking to
it.  I was getting hundreds of bounce messages to non-existent mail
addresses.  Convinced me real quick not to do a catch-all mailbox.
Implementing SPF reduced that by about 2/3 at first.  Now I don't see
any.