How to use Huawei mobile broadband moden E3372 on Ubuntu 20.04.3 Server?

[Bo Berglund]

I have a USB mobile broadband modem Huawei E3372, which works fine on Raspberry
Pi4.

Now I want to use it as a backup connection on my Ubuntu server so I plugged it
in there and it obtains a connection as shown by the blue lamp coming on after a
while.

But I get no info on Ubuntu command line:

$ ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.119.216  netmask 255.255.255.0  broadcast 192.168.119.255
        ether a4:ae:12:7f:4d:c3  txqueuelen 1000  (Ethernet)
        RX packets 31586730  bytes 37388071202 (37.3 GB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 22813892  bytes 22378617526 (22.3 GB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0


On the RPi4 it looks like this:

$ ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.119.164  netmask 255.255.255.0  broadcast 192.168.119.255
        inet6 fe80::3337:b743:ab20:ba24  prefixlen 64  scopeid 0x20<link>
        ether dc:a6:32:34:83:f8  txqueuelen 1000  (Ethernet)
        RX packets 1438292  bytes 316735023 (302.0 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 229894  bytes 13805670 (13.1 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.8.106  netmask 255.255.255.0  broadcast 192.168.8.255
        inet6 fe80::f979:ae78:fd83:1c35  prefixlen 64  scopeid 0x20<link>
        inet6 2a02:aa1:162e:877d:1329:c23f:b7ce:af71  prefixlen 64  scopeid
0x0<global>
        inet6 2a02:aa1:162e:877d:10:2030:4050:2  prefixlen 128  scopeid
0x0<global>
        ether 00:1e:10:1f:00:00  txqueuelen 1000  (Ethernet)
        RX packets 27  bytes 3265 (3.1 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 50  bytes 6817 (6.6 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0


So now I want to know how I can get it to work on Ubuntu...

In an old reply on AskUbuntu they said I should test using ip link, which
results in this:

$ ip link
7: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group
default qlen 1000
    link/ether 00:1e:10:1f:00:00 brd ff:ff:ff:ff:ff:ff


Note that eth1 *is* mentioned here but is not shown by ifconfig...

Any ideas where to go from here?


-- 
Bo Berglund
Developer in Sweden