This is probably a stupid question.

I have a m0n0wall on a soekris4501. One network Adapter is assigned as
WAN interface, another as LAN, where only one Computer is connected.

I want to plug a Laptop to the 3rd Interface and have the PC and the
Laptop communicating over the m0n0wall, i.e. m0n0wall would work as a
switch/hub then.

Is this possible? What do I have to think about? Is this about
bridging? Do I have to use a crossed network cable between notebook
and m0n0wall?

Thank you for any hint.