title: ASP.NET MVC eurl.axd errors
body: <p>Using the following steps:</p>
  
  <p>(I have checked <a href="https://stackoverflow.com/questions/2635320/asp-net-4-0-default-aspx-problem-on-iis6">this similar post</a>, which does not solve my problem.)</p>
  
  <ol>
  <li>Under Windows Server 2003/IIS6, I create a new site called "testapp"</li>
  <li>In VS2010, I create a new ASP.NET MVC 2 application.</li>
  <li><p>I add a view called "Info" with the following code:</p>
  
  <p></p>
  
  <pre><code>&lt;h2&gt;System&lt;/h2&gt;
  
  &lt;h3&gt;Request&lt;/h3&gt;
  
  &lt;%
      foreach (string key in Request.Headers)
      {
          Response.Write(string.Format("&lt;p&gt;{0}={1}&lt;/p&gt;"
                  , key
                  , Request.Headers[key])
                  );
      }
  
  
  %&gt;
  </code></pre>
  
  <p></p></li>
  </ol>
  
  <p>In addition to the standard headers I see this one:</p>
  
  <pre><code>   X-REWRITE-URL=/home/info/eurl.axd/e3299f29f8043d4f8a27e0f1d0c40971
  </code></pre>
  
  <p>I am using <a href="http://www.helicontech.com/isapi_rewrite/" rel="nofollow noreferrer">Helicon ISAPI Rewrite 3</a>, which is generating the "X-REWRITE-URL" header.</p>
  
  <p>My problem is this: where is the <code>/eurl.axd?....</code> coming from? I've seen <a href="http://www.asp.net/%28S%28ywiyuluxr3qb2dfva1z5lgeg%29%29/learn/whitepapers/aspnet4/breaking-changes#0.1__Toc256770153" rel="nofollow noreferrer">this article</a>, but since this is a blank app in a new folder with a new app pool, there are NO 2.0.* apps running within this web folder. There are no virtual folders pointing at another directory, etc. The site is configured for ASP.NET 4.0, which is registered correctly. </p>
  
  <p>The problem is that the eurl.axd is screwing with parameters in my MVC routes. </p>
  
  <p>The options in the "ASP.NET 4.0 Breaking Changes" article don't really work for me, because there aren't any 2.0 components in this app, and I need to use extensionless URLs. </p>
  
  <p><strong>Update</strong> I've just noticed that System.Web.MVC in the GAC is version 2.0.0.0. Should this have been updated to 4.0 with the installation of VS2010 and the 4.0 framework?</p>
  
  <p>I don't understand why I'm seeing this error with a default ASP.NET MVC 2 application. Help!!</p>
  
  <p><strong>Update 2/2011 - Resolved</strong></p>
  
  <p>Having finally tried disabling extensionless URLs via the registry hack, the problem disappeared. I find it counter-intuitive that disabling extensionless URLs makes extensionless URLs work (with the wildcard mapping in IIS6), but I'll take what I can get.</p>
  
  <p><strong>Update 12/2014</strong></p>
  
  <p>(Merry|Happy|Peaceful) (Christmas|Hanukkah|Kwanzaa|December).</p>
  
  <p>I forgot to mention that every other Windows update nuked the registry change. This appeared as weird problems where a request to <code>http://site.dom/bob</code> would fail, while <code>http://site.dom/bob/</code> would succeed. Have fun! (Notice the trailing slash.)</p>