How do I automatically sign out of Gmail but keep my two-factor authentication remembering my computer between browser sessions?

Question

I use Gmail's two-factor authentication (with Firefox). I would like it to remember certain trusted computers (across browser sessions) so that I don't have to use it every time I log into Gmail on those computers. As far as I can tell, this requires saving Gmail's cookies across browser sessions. But for security and privacy reasons, I would also like Gmail to automatically log out when I close my browser. As far as I can tell, this requires clearing Gmail's cookies between browser sessions.

Is there any way to either:

(a) clear Gmail's cookies between browser sessions but still get Gmail's 2FA to remember my computer, or
(b) save Gmail's cookies between browser sessions, but still get it to log out when I close my browser?

Answer 1

I'm afraid you can't have your cake and eat it too. How will Google know it's the same computer? Even if it is, how will they know it's you're user account? They can't rely on IP address, because those change. The only thing that's reasonable is cookies, since you're probably keeping the physical machine secure from bad actors. (And if you're not, you've got more problems than just giving away access to your email mailbox.)

So I'm afraid, no, there's no way to do what you want. You can either clear the cookies, or bypass 2FA on that computer at next login, but not both.