There are some really nice modules to add on to IIS7. One of the them URL Rewrite. You can also set up a Reverse Proxying rule. This basically allows you to re-route any traffic that might be specified in DNS to a different server. In this particular scenario, the DNS rules couldn’t be changed because they weren’t owned. However, because there is control over the destination server, I can re-route incoming traffic to a different server.
Double-click on URL Rewrite on the website that is accepting the incoming traffic. Then “Add Rule”. Select “Reverse Proxy” rule.
Now you can specify the new destination for all request. You can be a little more specific about links with regular expressions if necessary.
Now you can test your theory by opening your web browser and pointing to the original domain name. You can even rewrite links in the response.