[ Debug cookie use by a web site used for session maintenance ]

I have been trying to debug cookie use on a web site (projecteuler.net). As far as I can tell, this site uses cookies from four domains: projecteuler.net, google.com and mathjax.org. However, if even if I whitelist cookies from all three of these domains (in Firefox) I still lose my session and get logged out. However, if I set "allow all cookies" in Firefox, the session is preserved.

What could be happening here? Is the site setting a cookie then immediately deleting it or something?

Answer 1

I have discovered the problem. In Firefox, if you enter a domain for whitelisting, it automatically prepends an http:// at the front. It does not generically whitelist the domain. If the site uses a secure protocol then you may have to add whitelist entries specifically for that protocol, thus https://projecteuler.net or whatever, using the "https" explicitly.