Throttling data miners(leechers)

[Jayesh A Lalwani]

So, we have this yellow pages search website, that is basically open access. There is no login/password security, and we don;t want to force our users to register on the site to use it. Basically, any person that needs information should be able to go in and find a business

What we don't want is automated scripts trawling our website and leeching data out of it. Granted, we can't stop everyone, but we want to place limits on how many requests users can place on the website. So, even if a leecher wants to extract data out of us, the leecher should be well behaved and not overwhelm the system with requests

So, my question is can I use apache to throttle the number of requests from the same IP address? I know I can do it in my servlet, but I would rather do it before the request comes to the servlet. I know I can use apache to block IP addresses all together, but is throttling possible?