ASP.NET/IIS: 404 for all file types

Question

I set up 404 handler page in web.config, but it works ONLY when extension of URL is .aspx (or other which is handled by ASP.NET). I know I can setup static HTML page in webs

Answer 1

The web.config can only set up errors pages for pages controlled by it's web site. If you have any other pages outside the purview of the ASP.Net application, then you set up handling for them in IIS. There's an option in there for configuring the 404 page where you can point it to your custom page.