> Thanks. It looks like that folder exists at
> /etc/sysconfig/network/if-up.d/ although at the moment I have no idea
> how to make sure it only happens with usb networking.
looks like there is a variable ${IFACE} available.
you could check with
[ "$IFACE" != "usb0" ]
or something more sophisticated if you use more than one usbX device for
networking.