Network disconnected after a few hours

Hello, experts there

I have a new precision 5820 Tower PC delivered from DELL with Ubuntu 16.04 TLS OS installed two days ago.

I have an issue with this PC while remotely login and DELL support team think it is Ubuntu related.

here is what happens:

After less than two hours of login from reboot, the network connection to the PC is automatically cut off.
I went to the Lab where the PC is, touching keyboard or moving mouse will wake up the screen, on Ubuntu login screen, click on top-right , from network/connection information, shows no IP.
if I then first click “Disconnect” and later “my machine name” from network menu, the network will come back.

I have set

  1. the “Deep Sleep Control =Disabled” from BIOS /Power Management
  2. “don’t suspend “ from Ubuntu System Setting /power option
  3. also followed https://askubuntu.com/questions/452908/how-to-disable-suspend-in-14-04
    Create a new file
    sudo -H gedit /etc/polkit-1/localauthority/50-local.d/com.ubuntu.disable-suspend.pkla
    with the following contents:
    [
    [Disable suspend (upower)]
    Identity=unix-user:*
    Action=org.freedesktop.upower.suspend
    ResultActive=no
    ResultInactive=no
    ResultAny=no

[Disable suspend (logind)]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend
ResultActive=no
ResultInactive=no
ResultAny=no

[Disable suspend when others are logged in (logind)]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend-multiple-sessions
ResultActive=no
ResultInactive=no
ResultAny=no
]

This is weird. This PC is required to be able to work remotely.

Have I missed any setting? Do you have any suggestion?

Look forward to hearing from you soon

Cheers

Xiaofeng

I’ve moved this to the https://community.ubuntu.com/c/support-help-requests category because this site isn’t designed to take tech support questions. Sorry. I’d recommend using one of the official support channels listed on the https://community.ubuntu.com/t/finding-help/712 page.