I worked with a customer recently who needed to set up an HTTP redirection using the Error Pages in IIS 7.5. After setting up a custom error page with a static resource for an HTTP 401.1 error code, the redirection still showed the default IIS 401.1 page. We had to work to determine the cause of these IIS HTTP redirect problems in v7.5.
Why IIS HTTP Redirect Problems in v7 and v7.5?
We investigated a bit and noticed a subtle problem caused by how we accessed the site to test HTTP redirects. If you’re testing from a local client on the same web server, you need to ensure the Custom error pages option is enabled in the feature settings for Error Pages in IIS. From the Error Pages feature in IIS Manager, click Edit Feature Settings and make sure Custom error pages is checked if you are testing this from the web server itself. If you are testing remotely, you can leave Detailed errors for local requests and custom error pages for remote requests is checked.