However, to make tracing less obtrusive, you can disable pageOutput and then request tracing information using a special file called Trace.axd. This is a virtual file, which means you won’t find it in your website when you go looking for it. However, the ASP.NET run time knows it should provide you with tracing information when you request this special page. Although the file is virtual, you can still protect it using ASP.NET’s URL security by adding a // element to the main Web.config file as you’ve done with other file and folders.