NetworkManager doesn't show ethernet connection

Question

So after upgrading from Ubuntu 16.04 to 16.10 I noticed that my eth0 device had disappeared. My machine also doesn't connect to the network by default, and the connection is not shown in gnome's NetworkManager.

dmesg output reveals that the device has been renamed:

[    1.109498] igb 0000:26:00.0 enp38s0: renamed from eth0

and I can get the connection working by running ifconfig enp38s0 0.0.0.0 0.0.0.0 && dhclient.

From here, how do I

• persist this so the connection is established automatically
• get the device to show in NetworkManager

Already had a look in /etc/network/interfaces and neither eth0 nor enp38s0 are listed there.

Solution 1

So I desperately tried to find the config issues in /etc/NetworkManager/ but didn't realise that /usr/lib/NetworkManager exists as well.

The problem was in /usr/lib/NetworkManager/conf.d/10-globally-managed-devices.conf:

[keyfile]
unmanaged-devices=*,except:type:wifi,except:type:wwan

I ended up removing the file completely, quick reboot and all is working again.

Solution 2

A fresh install, to server 17.10 with LXDE had this issue reading all over and trying everything. This also prevented me from using openvpn via network manager.

The following fixed the issue:

My /etc/network/interfaces file: removed all lines except:

auto lo
iface lo inet loopback

Then I edited /etc/NetworkManager/NetworkManager.conf from:

[main]
plugins=ifupdown,keyfile

[ifupdown]
managed=true

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

Add in [keyfile] string

[keyfile]
unmanaged-devices=*,except:type:wifi,except:type:wwan,except:type:ethernet

Current /etc/NetworkManager/NetworkManager.conf

[main]
plugins=ifupdown,keyfile

[keyfile]  
unmanaged-devices=*,except:type:wifi,except:type:wwan,except:type:ethernet

[ifupdown]
managed=true

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

Last run command:

sudo service network-manager restart 

and all showed correctly in the network manger after a couple hours of fighting! This is for a home server, it may have been caused me configuring the IP during setup, which added values for a static IP in /etc/network/interfaces .

Solution 3

I had the same problem and just add ,except:type:ethernet to /etc/NetworkManager/NetworkManager.conf

result is :

[main]
plugins=ifupdown,keyfile

[keyfile]
unmanaged-devices=*,except:type:wifi,except:type:wwan,except:type:ethernet

[ifupdown]
managed=true

Comments

[Maxim Imakaev]

For me, all the interfaces in network manager disappeared. My system won't DHCP after reboot, although would run "dhclient" manually just fine. I tried reinstalling network manager, purging all the config files - nothing helped! Finally, this solution helped.

[user3757405]

My Ubuntu (16.04) doesn't seem to have a conf.d subfolder in the /usr/lib location, and the only file in the /etc conf.d folder is default-wifi-powersave-on.conf. Perhaps we're using different versions/distros?

[user3757405]

I don't have a [keyfile] section in my conf file. Would it still help to add this, or is the default likely to be OK?

[yannux]

Yes I think you can, if it cause problem just remove it. I'm running 18.04 and I don't use that anymore

[Soheil Pourbafrani]

Worked on Ubuntu 18.04

[Gui Ambros]

Thank you! It worked perfectly on a freshly installed Ubuntu 20.04 as well.

[kikea]

Thank you. it did the magick!

[Wboy]

after hours of searching, this did the trick. thank you!