14

After one of Ubuntu updates I got my Ethernet connection unmanaged and not working when OS is loaded.

I tried different solutions, posted in internet:
No wired connection - Wired unmanaged ubuntu 18.04
https://superuser.com/questions/1429490/unmanaged-network-manager-in-ubuntu
https://forum.linuxconfig.org/t/wired-unmanaged-ubuntu-desktop-issue/1574
network manager says "device not managed"
Ethernet device not managed

Neither ow them worked.

Also I tried to activate connection using nmtui tool, but I got following error:

││ Could not activate connection:       │  │  
││ Connection 'Wired connection 1' is   │  │  
││ not available on device eth0 because │  │ 
││ device is strictly unmanaged         │  │

To provide more context, here is the relevant system configuration information:

~$ cat /etc/NetworkManager/NetworkManager.conf
[main]
plugins=ifupdown,keyfile

[ifupdown]
managed=true


[device]
wifi.scan-rand-mac-address=no


[logging]
level=TRACE


~$ cat /etc/network/interfaces


interfaces(5) file used by ifup(8) and ifdown(8)


auto lo
iface lo inet loopback


~$ cat /etc/NetworkManager/conf.d/10-globally-managed-devices.conf 
[keyfile]
unmanaged-devices=none


~$ cat /usr/lib/NetworkManager/conf.d/10-globally-managed-devices.conf 
[keyfile]
unmanaged-devices=*,except:type:wifi,except:type:gsm,except:type:cdma


~$ cat /etc/netplan/.yaml
cat: '/etc/netplan/.yaml': No such file or directory


~$ sudo lshw -C network
  -network DISABLED

       description: Ethernet interface
       product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:02:00.0
       logical name: eth1
       version: 06
       serial: 50:e5:49:3c:26:4e
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical
       configuration: broadcast=yes driver=r8169 latency=0 link=no multicast=yes
       resources: irq:17 ioport:de00(size=256) memory:fbdff000-fbdfffff memory:fbdf8000-fbdfbfff
  -network DISABLED
       description: Ethernet interface
       product: IC Plus IP100A Integrated 10/100 Ethernet MAC + PHY
       vendor: Sundance Technology Inc / IC Plus Corp
       physical id: 1
       bus info: pci@0000:04:01.0
       logical name: eth0
       version: 31
       serial: c0:4a:00:01:19:7f
       width: 32 bits
       clock: 33MHz
       capabilities: pm bus_master cap_list rom ethernet physical
       configuration: broadcast=yes driver=sundance latency=64 maxlatency=10 mingnt=10 multicast=yes
       resources: irq:19 ioport:ef00(size=128) memory:fbcff000-fbcff1ff memory:fbc00000-fbc0ffff

Please note both Ethernet adapters are shown as network DISABLED in lshw output.

Ubuntu version (desktop)

NAME="Ubuntu"  
VERSION="20.04.1 LTS (Focal Fossa)"

Also I tried to load previous version of the kernel. Internet worked well there. But after I ran apt upgrade and rebooted machine - internet became broken there too.

So, for now I completely have no idea what to look further. Any ideas and suggestions are very welcome.

PS:
I got internet connection working by manual run operation sudo dhclient. After that my Ethernet adapter became IP address and internet started working.
Also it causes that both my Ethernet adapters are not DISABLED anymore in lshw command output.

But the device is still unmanaged. No internet icon in the GUI. No settings available in GUI for wired connection.

So the question is still open:
How can I get my wired connection managed back?

Alexander Stepaniuk
  • 241

2 Answers2

14

Create a file in /etc/netplan:

sudo -H gedit /etc/netplan/networkmanager.yaml

or

sudo pico /etc/netplan/networkmanager.yaml

Place this content in that file, keeping the exact same indentation, spacing, and no tabs:

network:
  version: 2
  renderer: NetworkManager

Then, in terminal:

sudo netplan generate

sudo netplan apply


reboot

Then use the NetworkManager GUI tools to configure your "Wired Connection".

Update #1:

When booted to a Ubuntu Live DVD/USB, ethernet works fine. Will need to reinstall Ubuntu.

heynnema
  • 73,649
13

I found this post, and tried many of the same things without any luck. What was successful for me:

nmcli n on

Now the previously managed devices are managed again.

Daniel Lawson
  • 231