How do I use the same gateway for multiple NICs?

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http://askubuntu.com – a newbie network administrator here... I have a PC, I want to use it as transparent proxy server and also running one virtual machine as MySQL server. I'm using 3 network cards: eth0 is used to connect the server to my router (WAN) (IP eth1 is used as gateway to share internet connection to my network (IP Can I use eth2 ( as bridged NIC to my virtual machine, so that eth2 will have the same gateway as eth1? Before I set the eth2, the proxy was working fine, I could connect to the Internet using client computer. But when I try set up eth2 at the same (HowTos)