Ethernet over USB stopped working: Cannot find device USB0

Question

I used Ethernet over USB for some years to connect from my Debian 8 workstation to a Linux device with g_multi running. Today it stopped working, although (everybody says that) "I didn't touch anything".

What I know:

• The device is okay (Ethernet over usb is fine on another machine)
• USB port and cable is okay (mass storage from the device is still mounted)
• lsmod lists usbnet, rndis_host, rndis_wlan and cdc_ether, as expected

• /etc/network/interfaces still reads: `

  allow-hotplug usb0
  auto usb0
  iface usb0 inet static
      address 192.168.42.10
      netmask 255.255.255.0
  

• ifup usb0 fails with -

  Cannot find device "usb0"
  Failed to bring up usb0.

• ifconfig usb0 doesn't find the device

• dmesg|grep usb0 gives me

  rndis_host 4-1.1:1.0 usb0: register 'rndis_host' at usb-0000:00:1d.0-1.1, RNDIS device, ee:00:...
  

I tried a reboot, which didn't help, but produced another strange effect: eth0 didn't start via the network manager. I had to put it in /etc/network/interfaces to get my network up.

Related or a different phenomenon?

Any hints on how to narrow where the problem is?

Answer 1

Solved: It's been an predictable network interface name issue, renaming usb0 to something weird. Why this happend all of a sudden after years? I don't know. Maybe for the first time the USB connection was aready established while booting, so the system decided to behave like a multi-netinterface machine?

Anyhow, the problem is solved.