[cd34]

the reason your earlier rules didn't work is that you were blocking the 'host' machine of domain.com from accessing your site. So, had their webserver tried to hit your server, they would have been blocked. This wasn't what you wanted.

In addition, by putting deny from domain.com in your .htaccess, you now forced apache to do a DNS lookup for EVERY request below that .htaccess -- that reverse dns lookup can really slow things down on a busy site.

The Rewrite Rules posted by xxxtreme look at the referrer as sent by the surfer's browser. I would suspect that is what you were really after.

if indeed it is a hitbot and not some form of hotlinking or unwanted traffic, your first rules would be correct, however, based on your test and stated results, I think you wanted to block the referrer, not the server.