You can define session lifetime settings for logging on to the appliance operating system. Session lifetime settings prevent administrators from keeping sessions open indefinitely, which leaves the sessions vulnerable to unauthorized access.
These settings apply to operating system access with an SSH client, the VMware vSphere Client, the Hyper-V System Center Virtual Machine Manager Console, or the Hyper-V Manager.
In the Operations Console, click Administration > Operating System Access.
Under Session Lifetime Settings, select Time out idle sessions,and enter the time out duration, if you want to time out sessions after a period of inactivity.