I’m not exactly sure what you are asking when you say “the same layer 2”. My lan is pretty simple. The machine that I’m testing the MAC address rules with is connected like this:
— Computer connected to a layer 2 switch.
–That layer 2 switch is connected to a layer 3 core switch.
–An Untangle Firewall box (it has two network interfaces set up in a bridged state) one interface is connected to the layer 3 switch, and the other is connected to the Zeroshell box.
–The Zeroshell box has two is doing routing between it’s two network interfaces, one of which is connected to the Untangle Firewall, the other to the internet router.