How to set up anti-spam policy for debian mail server

This article introduces how to deploy a powerful anti-spam system on Debian mail server, mainly using Postgrey graylist mechanism and SpamAssassin spam filter.

1. Use Postgrey to build a gray list

1. Install Postgrey: Use the following command to install the Postgrey package:

   sudo apt-get update && sudo apt-get -y install postgrey

2. Configure Postgrey: Edit /etc/default/postgrey file, modify POSTGREY_OPTS parameter, and set the delay time (units in seconds, such as 60 seconds):

   sudo nano /etc/default/postgrey

   Set POSTGREY_OPTS to:

   <code>POSTGREY_OPTS="-inet=127.0.0.1:10023 -delay=60"</code>

   Save and start the Postgrey service:

   sudo systemctl start postgrey

3. Integrate Postgrey to Postfix: Edit Postfix main configuration file /etc/postfix/main.cf and add the following line to the smtpd_recipient_restrictions parameter:

   <code>smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination, check_policy_service inet:127.0.0.1:10023</code>

   Save and reload Postfix configuration:

   sudo postfix reload

2. Use SpamAssassin to filter spam

1. Install SpamAssassin: Use the following command to install SpamAssassin:

   sudo apt-get update && sudo apt-get -y install spamassassin

2. Configure SpamAssassin: Modify /etc/spamassassin/local.cf file as needed. For example, enable HTML mail verification:

   <code>enable_html_validation</code>

3. Integrate SpamAssassin to Postfix: Edit /etc/postfix/main.cf file and add the following line:

   <code>content_filter = spamassassin</code>

   Save and reload Postfix configuration:

   sudo postfix reload

3. Other anti-spam strategies

In addition to the above methods, you can also consider:

• Blacklist/Whitelist: Configure blacklist and whitelist in /etc/postfix/main.cf to block or allow mail for specific IPs or domains respectively.
• Mail content filtering: Use more advanced mail server management tools to set filtering rules based on email subject or content.

Through the above steps, you can establish a multi-level anti-spam defense system on the Debian mail server. Please adjust the parameters according to actual conditions and regularly monitor the mail server log to ensure policy effectiveness.

The above is the detailed content of How to set up anti-spam policy for debian mail server. For more information, please follow other related articles on the PHP Chinese website!