I currently have an OpenWRT router I have been playing with it, and I have it almost the way I need it.
This router has a SIM card slot, and I am using an ATT&T sim card it works.
I have tested plugging in the cable modem into WAN check external IP (whatismyip.com) then I unplug the WAN check external IP, and it changes.
So it is failing over and back between 3G and WAN Cable Internet, What I would like is for it to Email me and CC others when it loses main connection. And when it is restored.
Is there any way to setup such stuff, If there anything like Luci-app that would be good.