No wired connection - Wired unmanaged ubuntu 18.04

Solution 1:

I had exactly the same problem, but then tracked down the following solution (via this article).

1. Edit /etc/NetworkManager/NetworkManager.conf (needs to be done with sudo) changing the line managed=false to read managed=true

2. Restart network manager with

   sudo service network-manager restart
   

Solution 2:

I faced wired unmanaged problem when installing ubuntu-desktop in a Ubuntu 18.04 server installation.

The solution that worked for me is to tell netplan to switch to NetworkManager renderer.

Edit /etc/netplan/50-cloud-init.yaml (or other yaml file you find in /etc/netplan/)

network:
    renderer: NetworkManager # add this line
    ethernets:
        enp2s0:
            dhcp4: true
    version: 2

And then run sudo netplan apply

Solution 3:

This solution(from this article) works for me:

sudo vi /etc/netplan/xxx.yaml add renderer: NetworkManager under version: 2.

Then, sudo service network-manager restart

Now you can find the adapter in setting>networks.

Solution 4:

I had that problem too and after several days I could resolve it, here is how:

Before I found above regarding edit: "/etc/NetworkManager/NetworkManager.conf" I found that under Bluetooth settings my stationary computer was in Airplane mode. Don't let me comment on how much sense that makes. As that didn't solve the problem I found above suggestion but that still didn't do it.

Fortunately, I have two different routers, one connects via DHCP, the other manual. Accidentally I switched to the manual connected router and the icon changed but still no Internet. I then checked the DNS entries for that connection and found them empty although set to auto. Filling in some DNS resolver got me to the Internet.

That "solution" inspired me to switch the DHCP connection to the other router from auto to manual and to fill in the DNS again. Voila, that did it.

In summary, there seems to be a problem to accept connection data deployed via DHCP.

Background Information

I run 18.04 and 14.04 on the very same computer. As in 14.04, there was absolutely no problem with my connections I was adamant to search elsewhere.