Transparent Proxy

[DAV]

im trying to create a bridge between the two ethernet interface.

 [ PC ] <---> [ PINEAPPLE ] <---> [ MAIN ROUTER ] <----> [ INTERWEBS ]

the WAN\LAN is connected to the MAIN home router (as a client), and the PoE is connect to the computer (and assigns ips via DHCP)

and i have a couple of questions..

1. How do i make the bridge work? i tried some iptable tricks, nothing worked, but than again, im not a iptables wizard..

2. Is it possible to make the bridge completely transparent?

i mean i want the router to assign it the same ip as the computer would get, and i want to make the computer think this is the main router.. (if it is even possible, i would like to spoof the mac address accordingly too.. :/)

thanks in advance guys!! :)