I'm late, but for this there are companies that sit in the middle and block crawlers, spambots and known-malicious addresses. Here's one I use: http://www.incap

I'm late, but for this there are companies that sit in the middle and block crawlers, spambots and known-malicious addresses. Here's one I use: http://www.incapsula.com/ http://www.incapsula.com/ So far I've been happy with it!