title: Some application alias names result in Error401.2: Unauthorised message on IIS
body: <p>I am experiencing a weird issue with application alias naming conventions in IIS</p>
  
  <p>I have an asp.net application deployed to a folder on my server "c:\sites\Demo52"</p>
  
  <p>In IIS under Default Web Site I add an application setting the alias to "Demo" and the physical path to point to my application at "c:\sites\Demo52".
  The application pool is set to DefaultAppPool  (.NET V4 Integrated)</p>
  
  <p>When I then browse the application I receive "Error message 401.2.: Unauthorized: Logon failed due to server configuration."</p>
  
  <p>Now, if I remove the application and start again, this time using an alias of "Aemo", when I browse the application it works perfectly.</p>
  
  <p>On further investigation it appears that some alias names do not work...
  Demo, Pemo, Remo</p>
  
  <p>and some do for example.
  Aemo, Bemo, Cemo, Eemo, Femo, Gemo, etc. to the end of the alphabet. </p>
  
  <p>In fact, it appears that Alias' starting with the letter D, P or R all fail.
  So, while "DickDastadly" fails miserably,  "CaptainCaveman" is just fine. </p>
  
  <p>Further to this, in our application's Web.config we have</p>
  
  <pre><code>&lt;authentication mode="None"&gt;
  </code></pre>
  
  <p>since we perform our own authentication.</p>
  
  <p>Setting</p>
  
  <pre><code>&lt;authentication mode="Forms"&gt;
  </code></pre>
  
  <p>resolves the 401 error for all alias names, however, we are then not necessarily performing our own authentication as we'd like and I can see nothing in our code that would even care about a sites alias.</p>
  
  <p>So, I'm wondering if anyone has experienced anything similar or has any views on how to mitigate this issue.</p>