How to setup network in ubuntu 20.04 via usb0 (Samsung in tethering mode)?

Question

linux

Good afternoon! I would like to ask the experts of ubuntu 20.04. I rolled up zero ubuntu, connected the amsung phone as a modem via usb. Everything worked ok, the network was configured via netplan with regards to the ethernet cable, and the usb modem was detected automatically and this was an internal magic. Then I wanted to install qemy / kvm and with it all sorts of network interfaces were installed, which, apparently, broke automagic for the usb modem. when the modem is connected, the interface appears, but in the down status. I'm trying to turn it on with the "ip link set usb0 up" command. It goes into the "UNKNOWN" state, and even all sorts of ipv6 addresses appear. Before installing qemy, an ip from the 192.168 network was automatically assigned to my interface. ** b The default route for the Internet was automatically assigned accordingly. I want to add that I don’t have the /etc/network/interfaces file, since everything is configured through netplan. I want to ask for your advice or some kind of hint, a guiding algorithm for diagnosing a problem.

Answer 1

I'm trying to turn it on with the "ip link set usb0 up" command.

Try to assign ipv4 manually:
ip a add 192.168.xy/24 dev usb0
In general, I would add it directly to the netplan config.

Answer 2

try these commands
sudo apt-get install --reinstall network-manager modemmanager