title: ProxyPreserveHost seems to do little for me
body: <p>I see many on the web referring to the use of <code>ProxyPreserveHost On</code> to make sure that a proxied backend receives the original caller's host name. I am using this to tighten my web application's security (Java, Tomcat) whereas it would also be nice if my logs would show where users are actually at. My Tomcat logs now show this &ndash; pretty useless:</p>
  
  <pre><code>127.0.0.1 - - [17/Mar/2013:06:32:13 +0100] "GET /webapp/frontend/app/partials/welcome.html HTTP/1.1" 200 54
  </code></pre>
  
  <p>This is my configuration that does clearly not work as expected:</p>
  
  <p>"/etc/apache2/sites-enabled/000-default"</p>
  
  <pre><code>&lt;VirtualHost *:80&gt;
  ProxyPreserveHost On
  ProxyPass /webapp http://localhost:8080/webapp
  ProxyPassReverse /webapp http://localhost:8080/webapp
  RewriteEngine On
  RewriteRule ^/$            /webapp/frontend/app/ [proxy]
  RewriteRule ^/webapp/$     /webapp/frontend/app/ [redirect]
  RewriteRule ^/webapp/app/$ /webapp/frontend/app/ [redirect]
  </code></pre>
  
  <p>(from here on default stuff that was in the <code>000-default</code>)</p>
  
  <p>Enabled modules:</p>
  
  <pre><code>sudo a2enmod proxy
  sudo a2enmod proxy_http
  sudo a2enmod rewrite
  </code></pre>
  
  <p>This is Ubuntu 12.10 running Apache HTTPD 2.2.22.</p>
  
  <p>Your help would be much appreciated.</p>