How to use custom Errors page in Windows Authentication

Question

I am using asp.net 3.5 web.config to limit access and it works great.

Answer 1

You won't see it - custom error pages are served by the ASP.NET application, but Windows auth is served up by IIS itself.

Now you can set IIS to use different error pages. For IIS7 this needs a separate configuration section;

And you'll need to ensure the app pool user has access to that path.