SpamAssassin is an open-source mail filter that identifies spam emails using a wide range of heuristic tests. This guide explains how to install SpamAssassin on Ubuntu 20.04 LTS or 21.04.
Prerequisites
- Deploy an Ubuntu cloud server instance at Rcs.
- Install Postfix mail transfer agent.
- Create a sudo user.
- Verify the server has outbound port 25 open.
1. Install SpamAssassin
Connect to your server with SSH.
Install SpamAssassin.
$ sudo apt-get update $ sudo apt-get install spamassassin spamc -y
Add a SpamAssassin user and disable the login.
$ sudo adduser spamd --disabled-login
2. Configure SpamAssassin
Assign the spamd
user account to SpamAssassin and set the log and default home directories.
Edit the configuration settings.
$ sudo nano /etc/default/spamassassin
Find the line:
ENABLED=1
Uncomment it by removing
#
and change the value from1
to0
.ENABLED=0
Find the line:
OPTIONS="--create-prefs --max-children 5 --helper-home-dir"
Change it to include the SpamAssassin user account and log files directory.
OPTIONS="--create-prefs --max-children 5 --username spamd --helper-home-dir /home/spamd/ -s /home/spamd/spamd.log"
Find the line:
CRON=0
Change the value from
0
to1
.CRON=1
Save and close the file.
Make a backup of the SpamAssassin local configuration file.
$ sudo mv /etc/spamassassin/local.cf /etc/spamassassin/local.cf.bk
Create a new SpamAssassin local configuration file.
$ sudo nano /etc/spamassassin/local.cf
Paste the information below to the file.
rewrite_header Subject ***** SPAM _SCORE_ ***** report_safe 0 required_score 5.0 use_bayes 1 use_bayes_rules 1 bayes_auto_learn 1 skip_rbl_checks 0 use_razor2 0 use_dcc 0 use_pyzor 0 ifplugin Mail::SpamAssassin::Plugin::Shortcircuit endif
Save and close the file.
3. Configure Postfix
Edit your Postfix configuration file.
$ sudo nano /etc/postfix/master.cf
Locate these entries.
smtp inet n - y - - smtpd #smtp inet n - y - 1 postscreen #smtpd pass - - y - - smtpd #dnsblog unix - - y - 0 dnsblog #tlsproxy unix - - y - 0 tlsproxy submission inet n - y - - smtpd
Below the
smtp
configuration, add a SpamAssassin content filter.smtp inet n - y - - smtpd -o content_filter=spamassassin spamassassin unix - n n - - pipe user=spamd argv=/usr/bin/spamc -f -e /usr/sbin/sendmail -oi -f ${sender} ${recipient}
Save and close the file.
Restart Postfix and enable SpamAssassin to run at system startup.
$ sudo systemctl restart postfix.service $ sudo systemctl enable spamassassin.service $ sudo systemctl start spamassassin.service
More Information
To learn more about SpamAssassin, please see the official website.