I have been having this issue with one of my client's installation for past two weeks. For some reason, the server shuts down automatically. I went through the log file (message) and the last message which is displayed before system goes down is: v2 kernel: e1000: eth0: e1000_watchdog_task: NIC Link is Down the problem started to happen about two weeks ago. There was nothing changed or updated on this system so it is quite puzzling for me. I haven't been able to figure out why this happening. Since yesterday afternoon, the system restarted three times at night. Does anyone have any idea why this is happening?