Rewrite URL

And the error you are getting is because you changed the host header but did not modify the request URI to remove the "directory1" portion. Also be aware that you have to reverse this whole process if the server sends redirects which are very common. For example, if you got the URI http://server1.company.de/directory2/ to successfully map to http://server12.company.de/directory/ try going to the same URI without the trailing slash. The server will send the browser a redirect to http://server12.company.de/directory/ which you then have to modify back to http://server1.company.de/directory2/ in the headers on the way back to the client.