How does CodeIgniter know a cookie holds valid session data?

Question

In CodeIgniter, session data are saved in a cookie by default. But there must be also a file on my server (named as the session ID) to verify that the data (in the cookie) i

Answer 1

Just tested this today with Firebug..

To follow up on Shanee's answer, in CodeIgniter's "application/config/config.php" file, if one sets:

$config['sess_use_database'] = TRUE;

then only the default CI session data: session_id, IP_address.., is stored as a browser cookie.

Any additional custom data provided by the set_userdata() function, such as usernames and passwords, are no longer part of the cookie but are instead stored in your database.