问题
I have a custom error page that should display for HTTP 404 errors. It does not and I am having difficulty figuring out why.
My web.config is set
<customErrors mode="On" />
Fiddler shows a 401.2, followed by a 404 for a single POST. Both errors should be custom. The 401.2 is working because I see it in fiddler. The 404 happens immediately after so all I see in the browser is the generic 404 error. I should see my custom 404 page.
Why won't my custom HTTP 404 page showup?
回答1:
What's the URL you are testing with? If it's not a file type handled by ASP.NET (e.g. /foo/bar.txt) then you won't see the ASP.NET defined 404 handler.
-Oisin
回答2:
If you're looking for what the 404.x codes mean here's this
HTTP 404.x-File or Directory Not Found
- None - File or directory not found.
- 1 - Web site not accessible on the requested port.
- 2 - Web service extension lockdown policy prevents this request.
- 3 - MIME map policy prevents this request.
Seems to be an IIS specific code, not sure if IIS sends these details with the response
来源：https://stackoverflow.com/questions/5748304/iis6-why-wont-my-custom-error-page-display