There is a following setup on Mikrotik map lite:

eth1 - device management with winbox
wlan1 - wifi access to internet
l2tp2 - vpn server
wlan2 - network for clients

where wlan2 exists only when wlan1 connection has been established and then clients on wlan2 have access to internet via vpn.

I'm trying to understand how to get internet on cable with eth1 instead of wlan1, having both options enabled with the following logic:

- use internet from cable when it is connected, OR
- use internet from wlan1 when there's no cable on eth1