Knowledge base → Installing and configuring the SpamAssasin anti-spam filter and grouping messages into the Spam folder for Postfix Ubuntu service

Setting up the spamassassin anti-spam service on the Ubuntu\Debian mail server for the Postfix service and moving emails to the Spam folder. This configuration allows you to make working with mail comfortable by training the filter and automatically moving messages.

This guide assumes that you have already configured the mail server itself and that you need to configure the spam filter. More information about setting up a mail server can be found here:

• Linux Debian 12 corporate mail server with pre-configured services
  
  

You can also order a VPS with a pre-configured operating system and get a ready-made corporate mail server for the price of a VPS server.

1. Install the service spamassassin

apt-get install spamassassin spamc
adduser spamd --disabled-login

2. Let's set up the service

vi /etc/default/spamassassin

Find the line:

OPTIONS="--create-prefs --max-children 5 --helper-home-dir"

and replace with:

OPTIONS="--create-prefs --max-children 5 --username spamd --helper-home-dir /home/spamd/ -s /home/spamd/spamd.log"

At the very end of the file, include cron:

CRON=1

Let's save the file. (:wq)

3. Filter setting:

mv /etc/spamassassin/local.cf /etc/spamassassin/local.cf.bk

vi /etc/spamassassin/local.cf

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_pyzor 0
ifplugin Mail::SpamAssassin::Plugin::Shortcircuit
endif

Let's save the file.

4. Configuring the Postfix Service

Find the smtp line and add the configuration below:

vi /etc/postfix/master.cf

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 the file and restart the services

systemctl restart postfix.service
systemctl enable spamassassin.service
systemctl start spamassassin.service

Let's check the operation of the service by sending a letter containing this text to the mailbox:

XJS*C4JDBQADN1.NSBN3*2IDNEN*GTUBE-STANDARD-ANTI-UBE-TEST-EMAIL*C.34X

5. Set up moving spam emails to the Spam folder.

Install and configure the Sieve service

apt-get install dovecot-sieve dovecot-managesieved

vi /etc/dovecot/conf.d/90-sieve.conf

sieve = /etc/dovecot/dovecot.sieve

Let's save the file.

Let's create a file:

vi /etc/dovecot/dovecot.sieve

require "fileinto";
if header :contains "SPAM" "YES" {
fileinto "Junk";
}
if header :contains "X-Spam-Flag" "YES" {
fileinto "Junk";
}

Let's save the file.

Add the configuration to the end of the file:

vi /etc/dovecot/dovecot.conf

service stats {
unix_listener stats-reader {
user = vmail
group = vmail
mode = 0660
}
unix_listener stats-writer {
user = vmail
group = vmail
mode = 0660
}
}

Let's save the file.

Let's add the configuration to the file so that the line looks like this:

vi /etc/dovecot/conf.d/15-lda.conf

protocol lda {
mail_plugins = $mail_plugins sieve
}

Let's add the configuration to the file so that the line looks like this:

vi /etc/dovecot/conf.d/10-director.conf

protocol lmtp {
mail_plugins = $mail_plugins sieve
}

Let's restart the services:

systemctl start spamassassin.service 
systemctl restart postfix.service

Now all emails marked as spam will appear in the Spam folder.