How can I configure SpamAssassin to use a custom DNS resolver?

Question

How can I configure SpamAssassin to use a custom DNS resolver?

Answer

This can be done by creating a custom configuration file for SpamAssassin where a custom dns_server directive is added. This allows SpamAssassin to use a different DNS resolver then the configured system level resolvers.

1. Access the server's command line as the root user via SSH or Terminal in WHM.

2. Create a customization file, in this example we will use as resolv.cf, in the /etc/mail/spamassassin folder:

   # touch /etc/mail/spamassassin/resolv.cf

3. Add the desired dns_server configuration to the file using your preferred text editor.

   CONFIG_TEXT: dns_server 4.2.2.1

4. Check the rule syntax for errors.

   # /usr/local/cpanel/3rdparty/bin/spamassassin --lint

5. Restart the spamd service to apply the change:

   # /usr/local/cpanel/scripts/restartsrv_spamd