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Anyone can point their domain to any IP address they want.  I've found at least two domains (same owner) with two totally unrelated domains (to each other and to us) that are currently pointing their domains to our  IP address.  The IP address is on our dedicated server (we control the entire physical server) and is exclusive to only that one domain (so it isn't a virtual hosting misconfiguration issue) This has caused Google to index their two domains with duplicate content from our site (found by searching for site:www.theirdomain.com)  Their site does not come up in the first 50 results though for any of the keywords we come up for so Google obviously knows THEY are the dupe content, not us (our site has been around for 12 years - much longer than them.) Their registration is private and we have not been able to contact these people.  I'm not sure if this is just a mistake on the DNS for the two domains or it is someone doing this intentionally to try to harm our ranking.  It has been going on for a while, so it is most likely not a mistake for two live sites as they would have noticed long ago they were pointing to the wrong IP. I can think of a variety of actions to take but I can find no information anywhere regarding what Google officially recommends doing in this situation, assuming you can't get a response.  Here's my ideas. a) Approach it as a Digital Copyright Violation and go through the lengthy process of having their site taken down.  Pro: Eliminates the issue.  Con: Sort of a pain and we could be leaving possibly some link juice on the table? b) Modify .htaccess to do a 301 redirect from any URL not using our domain, to our domain.  This means Google is going to see several domains all pointing to the same IP and all except our domain, 301 redirecting to our domain.  Not sure if THAT will harm (or help) us?  Would we not receive link juice then from any site out there that was linking to these other domains?  Con: Google will see the context of the backlinks and their link text will not be related at all to our site.  In addition, if any of these other domains pointing to our IP have backlinks from 'bad neighborhoods' I assume it could hurt us? c) Modify .htaccess to do a 404 File Not Found or 403 forbidden error? I posted in other forums and have gotten suggestions that are all over the map.  In many cases the posters don't even understand what I'm talking about - thinking they are just normal backlinks. Argh! So I'm taking this to "The Experts" on SEOMoz.