title: IIS7 Custom Error URL Redirects Not Working with non-physical files
body: <p>So here's the issue.  We run Sitecore, which does URL rewriting, and allows for something like example.com/Folder/Page.aspx to be a proper URL.</p>
  
  <p>Now, "Folder" doesn't actually exist on the file system, and neither does "Page.aspx".  But those URL's work, because ASP.NET does what it's supposed to.</p>
  
  <p>Okay, so now say I try to go to a web page that doesn't exist like example.com/idontexist.html.  This doesn't exist in on the file system, and doesn't use ASP.NET to resolve the file, so then we get a IIS7 404 Error.  </p>
  
  <p>Now, I want to change the 404 Error Page to a Custom Error Page, by using a URL.  Say, the URL is example.com/ErrorPage.aspx.  This page is actually, not a physical page, but an item in Sitecore.</p>
  
  <p>In the Custom Error configuration in IIS Manager, I am trying to change the 404 Error to point to a "URL Redirect" and I'm using "/ErrorPage.aspx" as the URL redirect.  When I try to then go to a URL that doesn't exist, IIS7 blows up with an error saying that it can't find /ErrorPage.aspx.</p>
  
  <p>In IIS6, this isn't an issue, and everything works fine.  But on IIS7, I redirect to a URL that isn't physically on the server.  </p>
  
  <p>Help! </p>