Setting up a bridge
Bridge two internal ethernet ports, one connected to the LAN, one connected to wingman.
wingman to eth1 <-> eth0 to LAN
First right click the NetworkManager applet and disable networking.
brctl addbr br0 brctl stp br0 off brctl addif br0 eth0 brctl addif br0 eth1 ifconfig eth0 down ifconfig eth1 down ifconfig eth0 0.0.0.0 up ifconfig eth1 0.0.0.0 up ifup br0=eth2
(eth2 is really just a /etc/network/interfaces definition for dhcp)