How to get eth0 and wlan0 back on Ubuntu Mate 18.04?

[Ralf Mardorf]

On Sun, 31 Jan 2021 12:02:54 +0100, Ralf Mardorf via ubuntu-users wrote:
>On Sun, 31 Jan 2021 08:37:50 +0100, Bo Berglund wrote:
>>/etc/network/interfaces  
>
>You aren't managing networks by NetworkManager, Wicd, systemd-networkd,
>Netplan, something else?

https://linuxconfig.org/how-to-switch-back-networking-to-etc-network-interfaces-on-ubuntu-20-04-focal-fossa-linux