Ethernet device not managed

Question

I am using Ubuntu 16.10 and recently I have not been able to connect to internet using Ethernet. The network manager shows device not managed. The WiFi network is working fine.

I've tried the solution from this questionn Ubuntu 16.04 Ethernet issues with no use.

My /etc/network/interfaces file:

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

My /etc/NetworkManager/NetworkManager.conf file:

[main]
plugins=ifupdown,keyfile,ofono
dns=dnsmasq

[ifupdown]
managed=true

Output of nmcli d:

DEVICE  TYPE      STATE      CONNECTION 
wlp2s0  wifi      connected  eduroam    
enp8s0  ethernet  unmanaged  --         
lo      loopback  unmanaged  --   

Answer 1

The following bug in Ubuntu 16.10 might be related: network-manager does not manage ethernet and bluetooth interfaces when Ubuntu 16.10 is installed using chroot/netboot method

First try running the following command:

sudo nmcli dev set enp8s0 managed yes

If you get the error message:

Error: Device 'enp8s0' not found.

Try running the command below:

ip link show

and look for a device name similar to enp8s0 and substitute it in the original command.

---

If the that didn't solve the problem, try running the following (backup orig file, and create 0 bytes file instead)

sudo mv /etc/NetworkManager/conf.d/10-globally-managed-devices.conf  /etc/NetworkManager/conf.d/10-globally-managed-devices.conf_orig
sudo touch /etc/NetworkManager/conf.d/10-globally-managed-devices.conf  

@datka reported a different location for The file 10-globally-managed-devices.conf so the commands should be:

sudo mv /usr/lib/NetworkManager/conf.d/10-globally-managed-devices.conf  /usr/lib/NetworkManager/conf.d/10-globally-managed-devices.conf_orig
sudo touch /usr/lib/NetworkManager/conf.d/10-globally-managed-devices.conf

The reboot, or restart the Network Manager service:

sudo systemctl restart NetworkManager

or the old way:

sudo service network-manager restart

Answer 2

In my case the 10-globally-managed-devices.conf just doesn't exist (from 16.04->16.10). All that is needed is to create it:

sudo touch /etc/NetworkManager/conf.d/10-globally-managed-devices.conf

Followed by a restart:

sudo service network-manager restart

Answer 3

While the advice to create an empty /etc/NetworkManager/conf.d/10-globally-managed-devices.conf file worked for me, I found another way to fix this.

Calling nmcli, I noticed that my ethernet device isn't classified as one of the types (wifi, wwan) that are excluded from the unmanaged-devices clause, in contrast to the WiFi device, but as ethernet:

$ sudo nmcli 
enp0s31f6: verbunden to Kabelgebundene Verbindung 1
        "Intel Ethernet Connection I219-V"
        ethernet (e1000e), 54:E1:AD:FC:E1:22, hw, mtu 1500
        ^^^^^^^^
        [...]

wlp5s0: nicht verfügbar
        "Intel Wireless 8260 (Dual Band Wireless-AC 8260)"
        wifi (iwlwifi), 28:C6:3F:CD:A1:9F, hw, mtu 1500
        ^^^^
        [...]

Adding that type to the exceptions in /usr/lib/NetworkManager/conf.d/10-globally-managed-devices.conf did work for me:

unmanaged-devices=*,except:type:wifi,except:type:wwan,except:type:ethernet
                                                     ^^^^^^^^^^^^^^^^^^^^^

Strangely enough, the original setting worked for me for more than 6 months, until I decided to clean out the packages installed on my system. However I can't tell if it was the device type or the file contents that have changed with that.

Answer 4

Setting unmanaged-devices=none in {BASE}usr/lib/NetworkManager/conf.d/10-globally-managed-devices.conf worked for me in getting NetworkManager to manage the ethernet port, though I don't know if that messes anything else up. :^)

This was for a Ubuntu 16.10 hybrid USB build.

Answer 5

Please be mindful that you may need to change the netplan renderer to NetworkManager.

In /etc/netplan/01-netcfg.yaml, or /etc/netplan/50-cloud-init.yaml, or (in my case) /etc/netplan/00-installer-config.yaml (it may be a different name but it should be the only file located in that directory) add renderer: NetworkManager after network:.

it should look something like this:

network:
  version: 2
  renderer: NetworkManager
  ethernets:
    enp0s3:
      dhcp4: yes

Please also be mindful that if you wish to add the exceptions tag to /usr/lib/NetworkManager/conf.d/10-globally-managed-devices.conf make sure that you add a plugin tag such as [keyfile] to the top of the file as per what plugins you have listed in /etc/NetworkManager/NetworkManager.conf [main] plugins=ifupdown,**keyfile**

Hope I could help, I'm running Ubuntu 20.04 and this had me scratching my head for a while.