how to avoid page caching on authentication? And CI session or PHP's $_SESSION ?

[eluser]Michael Wales[/eluser]
The first step in troubleshooting this would be to log a timestamp, user's IP address and their session ID. Then you will be able to confirm whether CI is issuing a unique certificate to each of these users or they are both using the same session. This "shouldn't" happen, since some info is stored in a cookie on the user's machine - but I have ran into scenarios where this did occur.

Have two users from the company access your application and look to see if you are getting log entries for each of them, if not - enterprise caching is the culprit.