What methods are available for dealing with spam on a shared webserver? It's a CPanel server and I'm bashing my head against trying to prevent people from being able to get an account, then start sending spam.
So far, I've tried using the built in hourly limit to emails (didn't work, set the limit to 20, sent myself 25 emails using mail(), and all went through), and that's really it.
Is there any clean solution to this? I haven't been able to find one online.