cPanel - howto prevent spam

[Le1]

Hello,
I'm using cPanel, and try everything that found on web to prevent spam from my server, but we are often in some DNSBL lists like barracude etc.

I changed many parameters from WHM, but as I know that limits are only for exim.
How can I detect and prevent those spammers who are sending spam from php scripts?
I'm using spamguard on another mail server, but there is a postfix. Does cPanel have some analog of spamguard ?

Thanks...