Fail Over:
SNAT
iptables -t nat -A POSTROUTING -o ethX -j MASQUERADE
iptables -t nat -A POSTROUTING -o ethX -j MASQUERADE
ROUTING
ip route replace default via (WAN1 GW ADDRESS) dev ethX metric 100
ip route replace default via (WAN2 GW ADDRESS) dev ethX metric 200
Load Balance:
ROUTING
ip route replace default \
nexthop via xx.xx.xx.xx dev ethX weight 2 \
nexthop via xx.xx.xx.xx dev ethX weight1
ACTIVE ROUTE CHECK
ip route show default