We have a problem in office when a user connects to our LAN without disconnecting from WiFi network he was previously on (a free WiFi provided by building owners). At a minimum, firewall log entries are cluttered with machine attempting to reach WiFi supplied DNS servers via fixed link. More of a threat is scenario when machine is hacked it can be used to bridge networks (public/private).
How to auto-disable wireless or auto-disconnect from it, if physical cable (ethernet) is plugged in?