Referred URL displaying null (Java, JSP)

Question

The page in question is a JSP page.

The page is on the web server which is being hit by external users using unconventional means. I don't know what is the previous page from which they are navigating away. I figured I can print out the header referred URL and their login credentials to track it down. Sometimes, there was a value for the referred URL (i.e. search engine query). Other times, it was null. I changed the name of the page, but there are still times where the the login and referred URL are null.

Why is the referred URL null? How can track down where the users were before they hit the page?

Thank you very much for any help. I appreciate it.

Answer 1

If the user stored the URL in favourite and accessed the page with it then the referrer header would not be set. And there might be some browsers not setting the referrer header for some secure reasons out there, so you can't really depend on the referrer header to tell you where the users were all the time.