[Dovecot] Dovecot and Bogofilter

Matthias Andree matthias.andree at gmx.de
Mon Nov 10 10:52:33 EET 2008

On Mon, 10 Nov 2008, Patrick Nagel wrote:

> Thorsten Vollmer wrote:
> > On Sun, 2008-11-09 at 22:39 +0100, Matthias-Christian Ott wrote:
> >> An other problem is that each mail needs to be initially classified and
> >> due to the fact that sieve is not able to execute external programmes,
> >> deliver has to do this task. I'm currently thinking of possibilities to
> >> implement this, so far I came up with the following:
> >>
> >>   1. Write a generic pipe plugin which can execute an arbitrary number of
> >>      programmes. The problem with this is that I'm not sure how to
> >>      integrate this is in Dovecot's configuration file. I thought of
> >>      something like this: pipe = prg1 | prg2
> > 
> > You do not need a plugin if you do the classification before the
> > delivery: MTA | classification | LDA
> With postfix, just add bogofilter as transport to master.cf and make it the
> 'mailbox_transport'.
> The problem with modifying the mail after reclassification persists, hope this
> can be solved. Then I could also finally move from
> postfix-procmail-bogofilter-cron-dovecot to
> postfix-deliver-antispam-bogofilter-dovecot. :)


it's not quite clear to me how this would work with bogofilter as a
mailbox_transport - bogofilter isn't designed to do final delivery.

It's also not quite clear to me why people would use procmail. Although
defended by its maintainers, it's an unusable and unconfigurable piece
of software from ancient past -- getting error handling right in
procmail is next to impossible, requires forfeiting :e rules and
bloating procmailrc with explicit error handling recipes.

If you want something and Dovecot's deliver doesn't fit your needs,
consider maildrop, <http://www.courier-mta.org/maildrop/>

Bogofilter has an "integrating-with-postfix" document in the doc/
directory that shows how to use Postfix's content_filter and does not
need procmail. Unfortunately, it does not show how to integrate updates;
there are several approaches to achieve that. One way is to use separate
mailboxes where users can send mail to and where they are picked up by
cron - best when using Dovecot is probably to make users move spam into
particular folders via IMAP.

I'm happy to update or add instructions to bogofilter, but may not have
the time to do sufficient R&D myself in the near future to obtain
relevant knowledge that I could document myself.

Matthias Andree

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