Use tthis method to test if the SpamHaus RBL checker works as expected.

 printf '%s\n' 'Received: from test.example (test.example [8.8.8.8]) by mx.example.com with ESMTP; Sun, 14 Sep 2026 11:00:00 +0200' 'From: test@example.com' 'To: test@example.com' 'Subject: ZEN test' '' 'Test' | spamassassin -D 2>&1 | grep -iE 'checking RBL zen'

If your RBL chain is working you see an output similar to this:

Use these simple verification tests to validate the spam checker works

Pass a spam email to SpamAssassin directly

$ spamc < spam_email.txt

The email should look like this:

./configure --enable-256-color --enable-xft \
--enable-font-styles --enable-transparency \
--enable-xim --enable-mousewheel --enable-text-blink \
--with-x --enable-perl --enable-combining \
--disable-pixbuf --disable-startup-notification \
--disable-next-scroll --disable-xterm-scroll \
--disable-rxvt-scroll --with-term=rxvt

dd bs=4M if=bootable.iso of=/dev/sdX conv=fdatasync status=progress oflag=sync

Replace X with your usb drive letter.