How to use two gateways with the same IP address?

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http://unix.stackexchange.com – I have to configure a NAT and manually split internet traffic between two gateways which are connected to a Linux box. There was no problem if each gateway has a specific IP address. I can do this by iproute2: ip route add default via dev eth1 ip route add via dev eth0 ip route add via dev eth0 But my problem is so simple! I have no access to change the gateways addresses, and network ids. I just need to use two internet gateways with the same address from a Linux box, with kernel 3.2.0 and above. (HowTos)