If you ever experience unexpected client SSH connections between your client workstation and Shaheen, you may want to investigate adding the following options to your local SSH config file (alternatively, they can invoked via ssh command line options):
ServerAliveInterval 120 For X11 timeout issues: ForwardX11Timeout 596h
These are simply guidelines that may help you with unexpected disconnects. There may be other network factors affecting connectivity between a workstation and a front-end node.