Do you have to have a switch or can you just put additional network cards in the pfsense box. my friend want to make a pf sense box but he doesnt have a switch. if you can would someone please link a guide. i did some searching on here but nothing answered my question.
It is possible to add additional NIC but i wouldn't recommend it.
He should just buy a cheap switch for 20.-
You don't have to have a switch, but will generally want one unless you don't need super-fast (gigabit) throughput between the hosts and must filter traffic between them for some reason. It's generally more sensible to get a switch, but depends on the circumstances.