Deterring Fraudulent Use
I'm interested in reducing fraudulent and malicious use of our servers. What policies have you all seen to be most effective at reducing malicious activity, while supporting and improving service for legitimate users.
I've had wannabe clients be so fucking brazen as to ask me if I had any email lists I'd sell them with their server! (Instant block) But is there an intelligence sharing organization perhaps, that other providers can feed in to in order to keep spammers/flooders off our networks?