On 10/12/2013 09:26 AM, Stan Hoeppner wrote:
> These two rules are adding 4.0 pts [...]
> Content analysis details:   (4.8 points, 4.2 required)
>  pts rule name              description
> ---- ---------------------------------------------------------------------
>  2.8 FSL_HELO_BARE_IP_2     FSL_HELO_BARE_IP_2
>  1.2 RCVD_NUMERIC_HELO      Received: contains an IP address used for HELO
>  0.8 BAYES_50               BODY: Bayes spam probability is 40 to 60%
>                             [score: 0.5314]

The others have addressed the "two rules" you mentioned, so I'll leave
that alone in this email.

There's more here than that:  If you're using Bayes, you have to train
it.  Right now, it's hurting you:  Those 0.8 points should be some
negative value, perhaps -1.9 or -0.5 (the default scores for BAYES_00
and BAYES_05), which would then have made that message score 2.1 or 3.5,
both of which are below your 4.2 threshold (which is already too low!).

On that threshold:  there are better ways to nail more spam than
lowering the threshold.  SpamAssassin is highly tuned for 5.0 and while
it's safe to bump that threshold up (more conservative, e.g. I block at
8.0 and flag at 5.0), it is not as safe to pull it down.

Better way #1: plugins.  Razor2, Pyzor, DCC.  Decently drop-in (though
DCC isn't as easy as it once was).

Better way #2: Bayes.  Set it up to facilitate better training.  Create
"learn-spam" and "learn-nonspam" folders for each user and run cron jobs
that run sa-learn (or better, spamassassin -r so you can learn and
report them) and then empty the folders.  Once you can trust Bayes, you
can increase the magnitude of its scores.  Do this slowly and carefully.

Better way #3: AWL.  This is now disabled by default, in part due to
misunderstandings (it is horribly named; it's as much a black list as it
is a white list, and it's not as "persistent" as its storage model
purports).  This nudges a sender's mail towards its previous average
score.  Set it up site-wide, /not/ per-user, and start it with a low
factor (say 0.1) until you can trust it, slowly increasing it up to 0.5
(you can go higher, but I wouldn't go too much higher; I use 0.333). 
Keep in mind that AWL doesn't clean up after itself the way Bayes does,
so the DB will grow over time.  There are limited guides online for how
to prune it.

> Received: from bendel.debian.org (bendel.debian.org [82.195.75.100])
>       by greer.hardwarefreak.com (Postfix) with ESMTP id C95BD6C0CE
>       for <s...@hardwarefreak.com>; Sat, 12 Oct 2013 10:23:37 -0500 (CDT)
> [...]
> X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on bendel.debian.org
> X-Spam-Level:
> X-Spam-Status: No, score=-9.6 required=4.0 tests=FOURLA,FREEMAIL_FROM,
>       LDOSUBSCRIBER,LDO_WHITELIST,RCVD_NUMERIC_HELO,T_RP_MATCHES_RCVD,
>       T_TO_NO_BRKTS_FREEMAIL autolearn=unavailable version=3.3.2
> [...]
> X-Amavis-Spam-Status: No, score=-5.735 tagged_above=-10000 required=5.3
>       tests=[BAYES_00=-2, FOURLA=0.1, FREEMAIL_FROM=0.001, LDO_WHITELIST=-5,
>       RCVD_IN_DNSWL_NONE=-0.0001, RCVD_NUMERIC_HELO=1.164,
>       T_RP_MATCHES_RCVD=-0.01, T_TO_NO_BRKTS_FREEMAIL=0.01] autolearn=ham

Another option is to trust Debian's SA instance.  You can add
82.195.75.100 to trusted_networks in your local.cf.  Be careful, this
would mean inheriting some of Debian's false negatives.

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