host header redirect (?) and hide URI

If you want to mask if from the end user, you can just change the "Host" header value in the HTTP_REQUEST event.

 when HTTP_REQUEST { 
   if ( [HTTP::host] eq "www.trees.somedomain.com" ) { 
     HTTP::header replace "Host" "www.outdoor.somedomain.com" 
     HTTP::uri "/trees" 
   } 
 }

Now, keep in mind that this will direct ALL requests to domain "www.trees.somedomain.com" to the backend server in the form of "http://www.outdoor.somedomain.com/trees". You will likely need to modify this a bit if you want to retain any portion of the original Uri in the request.

Hope this helps...

-Joe