I setup openvpn successfully on my Asus N16 router using Tomato, and now all traffic seems to be going through the vpn connection. However, I want to make sure that my ip address is not leaked in case the vpn connection goes down for whatever reason. I tried to google this and found a lot of people saying it's possible by using firewall rules. However, I am a newb with iptables and I couldn't find any useful examples that I can try. Can someone show me some example iptables rules that I can try? Thank you very much!