title: .NET HttpListener Prefix issue with anything other than localhost
body: <p>I'm trying to use C# and <code>HttpListener</code> with a prefix of anything other than localhost and it fails (i.e. if I give it <code>server1</code>, i.e.</p>
  
  <p><code>http://localhost:1234</code>  works, but</p>
  
  <p><code>http://server1:1234</code>  fails</p>
  
  <p>The code is...</p>
  
  <pre><code>HttpListener listener = new HttpListener();
  String prefix = @"http://server1:1234";
  listener.Prefixes.Add(prefix);
  listener.Start();
  </code></pre>
  
  <p>The failure occurs on <code>listener.Start()</code> with an exception of <code>Access is denied.</code>.</p>