ip route add table 5 192.168.0.0/24 via 10.1.1.1

iptables -t mangle -A PREROUTING -i <source_interface> -j CONNMARK --restore-mark --nfmask 0xffffffff --ctmask 0xffffffff
iptables -t mangle -A PREROUTING -i <source_interface> -j CONNMARK -p tcp --dport 80 -m conntrack --ctstate NEW --set-mark 0x10

ip route add table 8 default via 10.2.2.1
ip rule add from 172.16.0.0/24 lookup 8

ip rule add fwmark 0x10 lookup 8

ip route add default nexthop via 10.1.1.1 dev eth1 nexthop via 10.2.1.1 dev eth2

gem install fault_tolerant_router

sudo fault_tolerant_router generate config

fault_tolerant_router generate_iptables