I have an ASP.NET / ASP site which has been running for more than 15 years. If there is an unhandled exception, I made the system send me an email with the error details, using the Global.asax Application_Error method. Mainly, I get emails with errors "The file _____.aspx does not exist". Now, the filenames and their folders once really existed, but don't any more. I've search through all my codebase for the link to this file. I searched google with the "link:"-prefix, but I can't find any traces of which pages link to these nonexisting files.
I looked at HttpContext.Current.Request.UrlReferrer in the Globals.asax Application_Error method, trying to see where the nonexisting files are reffered, but it is always blank.
I'm thinking maybe to make a file there, with the correct name, and read the Browser history, but this is not possible? With the History object, I can only go back and forward.
My last solution would be to display a web page, and just ask the person browsing, how he got to this page.
Any other methods I can use to track this down?