I've been getting a lot of referrer spam on my server to various domains. A lot of it is attacking multiple domains. I've been looking around for solutions and I'm not sure what way to go. Looks like I should probably edit an Apache file somewhere.

http://en.wikipedia.org/wiki/Referer_spam

Those look like good ideas^

Where does Plesk hide the main Apache file and not just the per-domain ones? Will it overwrite that file on an update? Is there a better way to go about this?