Is there a way to check if a user already has a valid session on a different machine?
What I want to do is when a user logs in, destroy an other sessions which they
This may not be the best answer, but first thing that came to my mind was lowering the timeout on the session.
In app->config->session.php there's a setting for both lifetime and expire_on_close (browser).
I'd try looking into that for now, and see if someone else comes up with something better.