When you have a CLI session, that session remains open as long as there is activity. If you leave the session idle, the connection eventually times out and you must reconnect. The default timeout is five (5) minutes. You can set the timeout and other session-specific options using the line-vty command. For information about using this command, see the ProxySG Command Line Interface guide.
Here is an example of how to view your current line-vty configuration and how to change your CLI to two hours (120 minutes):
Enter configuration commands, one per line. End with CTRL-Z.
Line timeout: 5 minutes
Line width: 90 characters
Screen length: 35 lines
Telnet transparent: no
#(config line-vty)timeout 120