title: Authentication Subversion write-through proxy
body: <p>Since version 1.5 Subversion supports to have a local caching-proxy for the main Master-repository. </p>
  
  <p>I got the slave synced and the master replaying the commits to the slave. 
  Everything works fine so far, but now I am wondering how to do the authentication (working with <a href="http://blogs.open.collab.net/svn/2007/10/yesterday-at-th.html" rel="noreferrer">this</a> guide).</p>
  
  <p>When both, the master and the slave, have authentication set, the slave asks for username/password on reads, but both ask on writes.</p>
  
  <p>What is the way to also get authentication transparent to the user of the slave (meaning requiring only 1 authentication independent if it is read or write)?</p>
  
  <p>I am testing with:</p>
  
  <ul>
  <li>Apache/2.2.3, Subversion 1.4.2 on the slave (Debian)</li>
  <li>Apache/2.2.8, Subversion 1.5.1 (Ubuntu)</li>
  </ul>