title: No principal in request after Apache basic authentication (basic-auth) with mod_jk
body: <p><strong>Environment</strong></p>
  
  <p>Apache 2.2.13 connect to Tomcat 5.5 with mod_jk (ajp13). Apache requires basic-auth for "/" i.e. for all URLs it serves.</p>
  
  <p><strong>Problem</strong></p>
  
  <p>Once the request arrives at my app in Tomcat (it's a Servlet filter) <code>request.getUserPrincipal()</code> returns null. Apache, however, did authenticate the request. I did enter user/password in the browser's dialog.</p>
  
  <p>Any ideas?</p>