Yesterday I setup some software which tracks all http requests across our network of websites. After analyzing the first day of traffic we found nearly a dozen IP's that were flat out harvesting our data. It's pretty obvious when one ip browses 300 pages in a matter of 1 hour lol. I did do a reverse lookup on these and the majority were from Singapore, China, etc so they weren't search engine bots.
Does anyone know a service or website that maintains a list of bad IP's that should be blocked?
Yes there is a list of IPs which is dynamic. So there is no download for that list. But you can query it via DNS.
Have a look at the Http:BL of projecthoneypot.org: http://www.projecthoneypot.org/httpbl_api.php