The scenario is as follows: Linux box, running Debian, having two NICs (a broadband connection as well as a Wifi connection), both with DHCP and no information about the networks known in advance and subject to change over time. We want to use the wifi connection as default but automatically fallback to the broadband connection if the wifi connection fails for whatever reason. Additionally, once the wifi connection starts working again, we want to automatically go back to the wifi connection.Any idea how to set this up? I'm imaging to do this via ip routes, but the probing of the wifi connection should be fairly general like a ping to a specific server (the reason the check should be something like a ping is that the wifi connection might still be present, but the wifi itself is not connected to the internet anymore).
Two NICs with DHCP, use one as fallback
debian;wifi;iproute