source: npl/mailserver/dspam/dspam-3.10.2/doc/qmail.txt

$Id: qmail.txt,v 1.1 2005/03/11 21:16:03 jonz Exp $

QMAIL and VPOPMAIL INTEGRATION

qmail is designed with a modular system architecture, so there are a couple
of places to add dspam to such a system.  VPopmail extends the base qmail 
delivery process to handle virtual domains and users, which can reside in 
several different user databases.  Whether you want to add dspam at the
virtual domain level or user level largely determines the best way to add
it to your system.

USER-LEVEL INTEGRATION

If you are only configuring dspam for a small percentage of your users,
this is the best method. Configure dspam to use a standalone local delivery
agent like safecat (if you already use procmail or maildrop as an LDA, you
should call dspam from those tools directly). 

First, create a small script called maildir_mod in /usr/local/bin...

  #!/bin/sh
  VPOPDOMAINS="/home/vpopmail/domains"
  if [[ "$2" = "-d" ]]; then
      user=`eval echo $3 | cut -f 1 -d "@"`
      domain=`eval echo $3 | cut -f 2 -d "@"`
      cd $VPOPDOMAINS/"$domain"/"$user"
  fi
  /usr/local/bin/safecat "$1"/tmp "$1"/new 1>/dev/null

  NOTE: Be sure to configure VPOPDOMAINS to point to the path for your virtual
        domain directories

Now configure DSPAM:

./configure \
  --with-dspam-owner=vpopmail \
  --with-dspam-group=vchkpw \
  --with-delivery-agent="/usr/local/bin/maildir_mod Maildir -d %u" \
  # Your arguments

Next, create a .qmail file in the directory for the user with a line to
call dspam, like this:

 | /usr/local/bin/dspam --deliver=innocent --user $EXT@$USER

The two environment variables $EXT and $USER are created by the qmail-local 
program which begins the local delivery process.

DOMAIN-LEVEL INTEGRATION

If you're adding dspam for all users in a domain, you can add dspam
directly inline with the vpopmail LDA: vdelivermail.  In this mode, you don't
need to configure dspam to use a custom LDA, nor do you need to add a .qmail 
file for all users. Instead, you replace the existing line to the 
.qmail-default file at the virtual domain level, like this:

 | /usr/local/bin/dspam  --deliver=innocent --user $EXT@$USER  --stdout | /home/vpopmail/bin/vdelivermail '' bounce-no-mailbox

In essence, you just add the call to dspam (with the appropiate options
including --stdout) to the front of the existing line which vadddomain
creates when you add a domain.