Mandrake Single Network Firewall (three NIC support?)

I have the Mandrake SNF and I am wondering if the system will support one
external NIC and two NIC's for the internal network. I know a hub or switch
would solve this problem but I have enough NIC's and cable to do it with two
internal interfaces and not enough money to buy a hub/switch regardless of
price. (Financially challenged student)

TIA,
John Wheat