title: httplistener doesn't work on port 80?
body: <p>The setting: Windows 7, IIS installed and running.</p>
  
  <p>The following piece of code:</p>
  
  <pre><code>HttpListener listener = new HttpListener();
  listener.Prefixes.Add("http://server.com:8080/path");
  listener.Start();
  </code></pre>
  
  <p>Works like charm - any request made against the server is received in my code.</p>
  
  <p>However, when I make the following change (moving to port 80) http.sys/IIS (not sure which) returns HTTP 503 errors:</p>
  
  <pre><code>listener.Prefixes.Add("http://server.com:80/path");
  </code></pre>
  
  <p>I've tried setting URLACLs, running this process as admin, etc., but nothing changes this behavior.</p>
  
  <p>Edit: to clear this out - there is not actual networking involved in this mess. All this is done locally on a single machine, for testing purposes (both server and client).</p>
  
  <p>Any ideas?</p>