You mean other than that it's a tool used to launch DDoS attacks? Joke aside, Host: is optional in HTTP/1.0 (it's mandatory in HTTP/1.1). I would not be surpr

You mean other than that it's a tool used to launch DDoS attacks? Joke aside, Host: is optional in HTTP/1.0 (it's mandatory in HTTP/1.1). I would not be surprised if blocking on this cut out some set of proxies and spiders out there as well (whether these are customers you can't afford to block is another question).