4-C: RAZOR
apt-get install razor
#Added the following to spamassassin's local.cf file:
echo "razor_config /etc/razor/razor-agent.conf" >> /etc/mail/spamassassin/local.cf
#Then execute the following two commands:
razor-admin -d -home=/etc/razor -create
razor-admin -d -home=/etc/razor -register
#You can check the logs on /var/log/spamd/current for razor errors. Sometimes there are directory issues that can be easily corrected by symbolic links.