title: RewriteCond to change displayed host, but not server
body: <p>Typing out the title to this leads me to believe this might not be possible due to security concerns, but I will ask anyway.  I have shortcode support running on my server, lets call it <code>xx.yy</code></p>
  
  <p>I want it so when a user sends a request to <code>xx.yy</code>, it just changes the displayed host to another valid domain running on the same box.</p>
  
  <p>I have this so far (lets the server know to accept requests from <code>xx.yy</code>):</p>
  
  <pre><code>RewriteCond %{HTTP_HOST}   ^.*xx.yy [NC]
  RewriteRule ^/(.*)$ http://127.0.0.1:&lt;PORT_OMITTED&gt;%{REQUEST_URI} [P,QSA,L]
  
  RewriteCond %{HTTP_HOST}   ^.*mysite.com [NC]
  RewriteRule ^/(.*)$ http://127.0.0.1:&lt;PORT_OMITTED&gt;%{REQUEST_URI} [P,QSA,L]
  </code></pre>
  
  <p>It works, and it directs the traffic into my app, but the url says <code>http://xx.yy</code> when I would rather it say <code>http://mysite.com</code></p>
  
  <p>I know i could redirect to <code>http://mysite.com</code> instead of <code>127.0.0.1</code>, but I have 4 parallel boxes of <code>mysite.com</code> and going back out to DNS to maybe go to another box seems like a waste when I am already here.  Also, I am not sure how POST requests would work like that.</p>
  
  <p>What can I do?</p>