LGS105 Linksys Gigabit Switch 5 RJ45 ports, 10/100 / 1000Mbps, metal casing, Plug and Play (Accessory)
I connected this switch on port 1 output from an old box that was not the router. Then I plugged my 2 PC case CPL on ports 2 and 3 without installing anything. It has an installation CD, but I did not want to bother with that. And it works perfectly,