I've got a Zero set up with usb0 as g_ether and a static IP address:

usb0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 10.14.0.15  netmask 255.255.255.0  broadcast 10.14.0.255
        ether 7e:24:7d:cc:68:7c  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

I have the OTG port connected to one of the four USB ports on a 4b. I'm not sure what the next steps are to get the actual connectivity to function, though. I've seen posts saying that gadget mode is only supported on the USB-C port - does that only mean for using the 4b as a peripheral, or does that mean for any connectivity, even if it's the host?