FritzOver-Gateway is a python script, which changes the default route of a specific NIC if FritzBox fails link or ping.
I wrote this script because of my current ISP situation: My ISP currently does some maintenance and the connection drops for a few hours a day. Luckily, I've got a ThinkPad x230 with an UMTS module set up in my LAN. If the conneciton over fritzbox fails, the script changes the default gateway to my x230. 
FritzOver-Gateway uses following open-source projects:
- fritzconnection - Python-Tool to communicate with the AVM FritzBox
Edit the default values in the script or use env-variables.
| ENV | DESC |
|---|---|
FO_PING_HOST |
Host used for test-pings. |
FRITZBOX_GATEWAY |
address of the fritzbox |
FAILOVER_GATEWAY |
gateway to use if fritzbox fails |
FO_INTERFACE |
interface used within the fritzbox LAN |
FRITZBOX_PASSWORD |
password used to log into fritzbox's web-interface |