one of my sites has been getting visited by a specific ip address. this guy will go to my backlink, click on it, and come to my site. he has done this with several of my backlinks. he has also searched for a few keywords in google and come to my site. he was logged in, so the keywords are encrypted, but i am pretty sure they are my target keywords. this guy is doing extensive research on me. how do I stop him? if he comes to my site from that ip address, can i show "this site no longer exists" using htaccess?