Hello all,
i have 2 wan interfaces on the router for failover reasons. The secondary link is a metered 3G internet and because of that I need a script that will check which default route is active (reachable) and if it detects that 3G is active to block traffic to a specified IP lets say 10.0.0.2 which is an IP camera that can use up all of the bandwidht in few hours.
I tried to write it alone but i cant find out how to check with an IF statement the reachability of a route.
Can someone help me with this?

use netwatch

i dont know how to use netwatch for this scenario