I would like to be able to use my android phone as a backup internet connection if my home broadband goes down.
The idea is that if the network went down I would set up a static route on my home router to point all internet-bound traffic at the phone, and all the other devices on my LAN would be able to carry on using the internet without reconfiguring each one.
How can I get my android phone to perform IP forwarding/NAT from the wlan0 over the mobile data network? I don't want to put the phone into access point mode, but rather leave it connected to my home wifi network.
The phone is rooted so it feels like this should be possible with iptables but I'm not having much luck.