For some reason I have a site I am hosting that has been under a vampire like attack for some time. We already banned the useragent and the user banned all the ips in htaccess. So each of the bots only get a 403 when they hit the site yet the user is using over 500gb bandwidth per week all from the 403 errors. How big is the 403 response? Also it seems to still cause heavy php resource usage, is it also invoked in php? Would having a custom error page help?