Mailing List Message #14488
From: Max Lyth <>
Subject: Re: HOWTO add a Bayesian filter to SIMS
Date: Sat, 15 May 2004 19:42:51 +0100
To: SIMS Discussions <>
>> Despite the fact that the companies I service have migrated wholesale to OS
>> X I still find SIMS the easiest system to administrate but it's anti-spam
>> defences needed shoring up.
>> I therefore decided to look for a solution and found a free product called
>> ASSP that works very well with SIMS. I have written a description on how to
>> set this up which is a available at:
> Max, what effect does this have on SIMS' blacklists and RBLs? Are these
> rendered ineffective?
> Since ASSP acts as the SMTP proxy, sitting between the Internet and SIMS, and
> does the actual receiving of the email, I would expect that SIMS RBLs and
> blacklists would no longer be effective, if the ASSP setup is used. Mail
> 'coming in' to SIMS will be coming from, right?
> Then again, you call ASSP "a transparent SMTP proxy" which leads me to believe
> that maybe SIMS DOES still see the incoming IP address. Perhaps that's what
> "transparent" means... That, and you said in your write-up that: "not wanting
> to discard my beloved SIMS I decided to shore up the defenses with a Bayesian
> filter". Does ASSP 'shore up' (supplement) SIMS' defenses or replace them?
> Please clarify.

Warren, you are correct that using and SMTP proxy renders SIMS RBLs
ineffective but you are missing that ASSP supports RBLs itself. However I
should say that I never bothered to move my RBLs to ASSP as the Bayesian
filter and the collaborative adapting greylist work so well by themselves.

One problem with the ASSP solution is the name harvesting features of SIMS
works against you because if you have a lot of 404 user unknowns it is your
own proxy that get slowed. This has not been a problem so far for me but I
have suggested adding the feature to ASSP over on Sourceforge. If it is a
problem then you disable the SIMS anti harvesting features by editing the
resource, I'll consider adding this to the How-To.

Another potential problem is if you rely on POP before SMTP to temp white
list road warriors. You can use this if the users send direct to SIMS on
port 2525 but then you don't get the automatic WhiteList feature. On the
bright side SMTP-AUTH just works which is more than can be said for many of
the Exim-Postfix-Sendmail solutions out there.

Max Lyth
Technical Director
Automatic Software

18 Grove Mews, London W6 7HS, UK
Tel:+44 20 7354 7515          US Fax:(509) 277-5613
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