Spamassassin spam filter

Spamassassin version

Tested with Spamassassin 3.0.4.

Introduction

These instructions are adapted from this article. The result is that all mail will be filtered through Spamassassin, which adds a header like this to any messages it thinks are probably spam:

X-Spam-Flag: YES

Other programs can then treat those messages specially; see StandardSympa.

This requires Postfix set up as in StandardPostfix, and StandardPerlModules.

Installing Spamassassin

Install /usr/local/configure-wrappers/configure-spamassassin (make it world-executable).

Download the latest Spamassassin tarball. Compile and install:

tar zxf Mail-SpamAssassin-x.y.tar.gz
cd Mail-SpamAssassin-x.y
/usr/local/configure-wrappers/configure-spamassassin
make
sudo make install

In /etc/profile:

• Add /usr/local/spamassassin/bin to LOCAL_PATH.
• Add /usr/local/spamassassin/man to LOCAL_MANPATH.
• Add /usr/local/spamassassin//share/perl/5.8.4 to PERL5LIB.

Install:

• /etc/init.d/spamassassin (make it world-executable)
• /usr/local/spamassassin/etc/mail/spamassassin/local.cf

Make startup links to the init script:

sudo update-rc.d spamassassin defaults

Postfix filtering

Create a mail-filter user:

sudo adduser --system --group --home /var/spool/filter filter

Install:

• /usr/local/bin/filter.sh
• /etc/postfix/master.cf

Set the ownership and permissions of filter.sh:

sudo chown root:filter /usr/local/bin/filter.sh
sudo chmod 755 /usr/local/bin/filter.sh

Tell Postfix to reload its configuration:

sudo postfix reload

Note that the filter user will have its own Spamassassin configuration file in /var/spool/filter/.spamassassin/user_prefs. You can edit site-wide preferences in this file, or in /usr/local/spamassassin/etc/mail/spamassassin/local.cf. See the Spamassassin documentation for details of what you can put in these files.

Start Spamassassin

sudo /etc/init.d/spamassassin start

Procmail filtering

If you use Procmail to filter your email, put this in your ~/.procmailrc:

:0:
* ^X-Spam-Flag: YES
$HOME/Maildir/.Spam/

Upgrading

tar zxf Mail-SpamAssassin-x.y.tar.gz
cd Mail-SpamAssassin-x.y
/usr/local/configure-wrappers/configure-spamassassin
make
sudo /etc/init.d/spamassassin stop
sudo make install
sudo /etc/init.d/spamassassin start