I’ll give an example of installing and configuring Spamassassin to filter spam.
In Ubuntu Server, I switched to the root user and installed Spamassassin:
sudo -i
apt-get install spamassassin spamc
During installation, the user “debian-spamd” was automatically created.
In the file /etc/default/spamassassin, specify:
ENABLED=0
#OPTIONS="--create-prefs --max-children 5 --helper-home-dir"
OPTIONS="--create-prefs --max-children 5 --helper-home-dir --username debian-spamd -s /var/log/spamd.log"
CRON=1
In the file /etc/spamassassin/local.cf, specify:
rewrite_header Subject *****SPAM*****
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_pyzor 0
In the file /etc/postfix/master.cf we find the line:
smtp inet n - y - - smtpd
And under it, add a line through the space:
-o content_filter=spamassassin
And also add at the end of the file (before the last two lines and add spaces):
spamassassin unix - n n - - pipe
user=debian-spamd argv=/usr/bin/spamc -f -e
/usr/sbin/sendmail -oi -f ${sender} ${recipient}
Check the configuration of Postfix and restart it to apply the changes:
postfix check
systemctl status postfix.service
systemctl restart postfix.service
We activate spamassassin autostart when the operating system starts and start it:
systemctl status spamassassin.service
systemctl is-enabled spamassassin.service
systemctl enable spamassassin.service
systemctl restart spamassassin.service
See also my articles:
Installing and Configuring Postfix
How to configure SPF records
How to remove an IP address from email blacklists