The best way to back-up ethernet connection to ISP router is creating bridge from ETH1, ETH3 and enabling NAT on it. Don`t forget enable STP on bridge interface to avoid switching loops. STP will provide failover.
Routing and Bridging Firewall Solutions
The best way to back-up ethernet connection to ISP router is creating bridge from ETH1, ETH3 and enabling NAT on it. Don`t forget enable STP on bridge interface to avoid switching loops. STP will provide failover.