Dirk große Osterhues

*[MTA]: Mail Transfer Agent
This article describes the configuration of the spam scanner called spamassassin in conjunction with the MTA called Exim 4 in Ubuntu Linux (as of writing Ubuntu 11.10 is the most recent). Assuming an otherwise working Exim 4 setup, this document describes just the essential steps to a working spamscanner.

First, the necessary packages need to be installed:

aptitude install exim4-daemon-heavy sa-exim spamassassin

In /etc/default/spamassassin set the following lines:

ENABLED=1
CRON=1

The first option lets the spamassassin daemon start on boot. The second one defines that spamassassin's rules become updated each night using a cron job.

In order to check if the first steps went ok, it's time to start spamassassin the very first time:

service spamassassin start

To check if spamassassin runs smoothly on it's dedicated port, this command helps:

lsof -i :783

Now in /etc/exim4/exim4.conf.template, insert the following lines in MAIN CONFIGURATION SETTINGS:

local_scan_path = /usr/lib/exim4/local_scan/sa-exim.so

To enable Exim's spamassassin connector, the file /etc/exim4/sa-exim.conf has to be modified. Comment the following line in that file:

# SAEximRunCond: 0

In default setups, debugging is enabled. That will lead to huge log files. So for production use, changing the following line to zero is advised:

SAEximDebug: 0

The updated file /etc/exim4/exim4.conf.template becomes active by running the following line:

update-exim4.conf && service exim4 restart

For a basic protection, the MTA is now good to go.