Deploying ASP.net MVC to IIS 6 still returns 404

This morning I was checking my deployment instructions for an ASP.net MVC application, ideally this would be automated but that is my next task.

I was following Option 1 Steve Sanderson wrote on his blog, where you use Wildcard mapping for aspnet_isapi.dll. After setting up this while card mapping, you should be able to use the same pretty URLs without any modifications or additional mappings.

Unfortunately I didn’t read the post correctly and forgot to untick ‘Verify that file exists’,

As a result, I kept receiving 404 error messages – yet I knew that the path was correct.

It took me a while to figure out that I had forgot to untick the verify that file exists box.  Once the box had been set correctly, my content was serving again.

This raised an interesting question – why does ‘Verify that file exists’ need to be unticked? The executable is a ‘Win32 DLL (ISAPI extension)’, but not sure why this needs to be unticked – answers on a postcard (or a comment)!