rpi_usb_ethernet_gadget.md

The Problem

usb0 interface is DOWN.

Solution Part 1

Create a new connection: In /etc/network/interfaces.d/usb0.conf, write

allow-hotplug usb0
iface usb0 inet static
        address 192.168.7.2
        netmask 255.255.255.0
        network 192.168.7.0
        broadcast 192.168.7.255
        gateway 192.168.7.1

Solution Part 2

In /etc/udev/rules.d/99-usb0-managed.rules, write

ACTION=="add", SUBSYSTEM=="net", KERNEL=="usb0", ENV{NM_UNMANAGED}="0"

Source

Here