Thus spake Markus Illenseer
>  I like the idea which I have seen on my provider's list: A wrapper around
> sendmail which is able to protect you with one or two rules w/o the need
> to programm sendmail with its small abilities.
> 
>  More: http://www.obtuse.com/ follow smtpd.

I have been using this for a month now and it is great.  I use it with
smail rather than sendmail but it works the same way.  It has the added
advantage that the smtp daemon runs as a normal user rather than as root
so there is added safety as well.

I added a new option to it (I sent it back but I don't know when it
was/will be incorporated) that allow you to test out your rules before
committing them.  Very useful for making sure that you don't make a
mistake in the rule set.

The page http://www.druid.net/spam.html explains my spam blocking policy
to my users and talks about the mechanism.

-- 
D'Arcy J.M. Cain <darcy@{druid|vex}.net>   |  Democracy is three wolves
http://www.druid.net/darcy/                |  and a sheep voting on         
+1 416 424 2871     (DoD#0082)    (eNTP)   |  what's for dinner.