My clients are reporting quite a bit of spam and of course they don't want to spend the small fee we charge for a spam firewall from barracuda. So I have started enabling "spamassain" in cpanel and users are reporting over 50% of the spam gone. I find it hard to believe. But I can't find any good docs on it. Anyone care to share? Thanks
I don't know about cpanel, but Spamassassin is widely used and extremely good. It incorporates several different methods and systems to determine if an email is spam. I assume CPanel is just enabling Spamassassin that comes with fedora or whatever you are running. It's really not related to CPanel, just that CPanel can enable it, afaik. Here for info : http://spamassassin.apache.org/
Spamassassin will check it's host sender which those RBL database like spamcop.net to check whether their IP address is listed, if it is listed, it will not deliver the mail.