We are noticing that a significant amount of web traffic is from content scrapers (determined due to their crawling pattern). They are useless visitors to us but consume a lot of our resources (bandwidth, cpu). Is there any application/firewall to detect content scrapers and block them?
Excluding Search engine crawlers, they are not useless.
Note: I prefer to use existing solutions. It believe this is a common problem and there should be an existing solution.