Elmah and 404s under IIS6

Question

Just wondering if it's possible to get Elmah to log 404s that aren't picked up by the ASP.NET framework - i.e. the 404s that IIS spots and replies to.

Presumably this would involve some kind of entry in IIS -> web site properties -> Custom Errors tab.

Can't find any reference on how to do this.

Answer 1

Non-ASP.NET mapped extensions (e.g. static content, classic ASP, etc) will never hit the ASP.NET request pipeline so ELMAH will never know about 404 Not Found's generated by IIS6. You'd need to create a wild card extension mapping to aspnet_isapi.dll for this to be possible (or just specific extensions).