HTTP Request Throttle

I made a variation of this rule for rate limiting individual IP addresses and UserAgents, not to specific URIs but to all virtual servers covered by the rule, testing for x-forwarded-for, etc.. My tests performed very well so we tried it during a load test. The static variables needed to be tuned quite a bit, I don't recall what the final values were and I no longer have access to the production rule but I can get it if anyone is interested. We used it last night in production and it was very effective against rule breaking bots that are causing performance impact.