[CentOS] CentOS mailserver and spam filter setup ideas & preferences

Thu Dec 1 05:40:20 UTC 2005
Les Mikesell <lesmikesell at gmail.com>

On Wed, 2005-11-30 at 22:38, Gavin Carr wrote:
> > 
> > Yes, it is so far wrong and has licensing that prevents others from
> > fixing it that there is a project to completely replace the front
> > end component: http://smtpd.develooper.com/.
> 
> Hmmm, that's not quite how it happened. qpsmtpd was written by people who
> _like_ qmail but wanted to be able to do some funky things at smtp time
> that were never going to work shoehorned into qmail-smtpd. But I second
> the recommendation.

In code with more reasonable licensing, they could have reused
the existing code, adding what they wanted and fixing the
broken parts. Since it's qmail, they had to replace an
entire component.

> qpsmtpd also has a vanilla smtp-forward mode so you use it in front
> of any standard mta. The nice thing qpsmtpd brings to the table (as
> opposed to things like amavisd, MailScanner, etc.) is the ability to 
> identify and refuse spam at smtp time, often even before the mail data
> itself has been received, which translates to much lower load. Why
> accept spam at all to just bounce later?

Sendmail has that ability when you add suitable processing through
the milter interface.  The milter(s) run concurrently and can
respond at each phase of the smtp conversation so you can
reject based on content.  MimeDefang is a particularly handy
milter because it lets you control all of the things you might
want to do (spamassassin, virus scan, network checks, etc.)
in one place with a small snippet of perl, and it doesn't
affect anything sendmail already handles. For example,
why waste the CPU on the spamassassin scan if your access
rules already block the sender?

And if the original poster is still reading, there are
commercial versions (Canit and Canit Pro) that have
additional features like a web interface for individual
users to control their spam handling.
http://www.mimedefang.org
http://www.roaringpenguin.com/

-- 
  Les Mikesell
    lesmikesell at gmail.com