In article , Jeff Franks wrote:
Both of these are "blacklists" that many mailservers use to try to prevent
spamming.

I don't like blacklists for flat rejecting mail. I prefer to use a spam
scoring system - the one I use is called SpamAssassin, and I have it
installed on the mail server for everyone who uses my system to get
email. SpamAssassin assigns scores for each spam indicator - it uses a
combination of its own rules, a Baysean filter, the DCC and the Spamhaus RBL.
Matching a single rule - for example, if your IP address is in the SBL,
won't mean you get put in the spamtrap. For the rules-based filter, you
must match a few rules. SpamAssassin is very effective - much better
than using an RBL alone.

Here's a few stats for my personal email address for how many spam
emails I get per day:

Sat Nov 29 01:00:43 UTC 2003
101
Sun Nov 30 01:00:51 UTC 2003
102
Mon Dec 1 01:00:35 UTC 2003
114
Tue Dec 2 01:00:45 UTC 2003
115
Wed Dec 3 01:00:11 UTC 2003
131
Thu Dec 4 01:00:09 UTC 2003
117
Fri Dec 5 01:00:09 UTC 2003
98
Sat Dec 6 01:00:10 UTC 2003
94
Sun Dec 7 01:01:14 UTC 2003
105
Mon Dec 8 01:00:13 UTC 2003
103

I get perhaps 3 or 4 actual emails from real people per day (excluding
mailing lists). The scale of spam makes me wonder if email is really
worth it any more, since I get two orders of magnitude more spam than
ham. I have to waste time configuring SA, my server has to waste CPU
cycles and disk space.

Then there's worms/viruses. My mail server is configured to point-blank
reject *all* Windows executables. During the recent Swen scourge, at one
point Exim was rejecting several copies of the worm per minute. The
mailserver literally had to reject gigabytes of Swen. Swen must have
brought some smaller ISPs to their knees - I was just processing mail
for a handful of users - just imagine the traffic for a couple of
thousand users!

Unfortunately, the MAPS RBL is not a solution - it's like a blunderbuss
- it's fairly indiscriminate and inaccurate: many false positives and
fairly ineffective blocking. I won't even use the MAPS RBL as a rule for
SpamAssassin.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"