Usually the infrared port must be disabled in order to free up an IRQ for the second card, for example. This guide describes the installation of a firewall computer on a traditional 10BaseT Ethernet network, but the network could also be a wireless or phone-line networking system. The fastest connection and the lowest cost Traditional Ethernet with twisted-pair wiring is a proven, reliable networking system. Of all home networking solutions, an Ethernet network will provide the fastest performance. It is also the least expensive solution.
Every hub has an uplink port that is used to connect additional hubs in a chain.
You'll need one port for the firewall computer and one port for your primary computer. So, on a four-port hub where one of the four ports is an uplink port, this would leave only one additional connection. The home network kits that are currently being sold at most computer stores can be a good choice because they include everything you need to hook up two PCs. Extra cards and cables can be purchased for additional computers. If you get a kit, make sure that Linux drivers are available for the type of Ethernet cards you get.