Networking question

ok well this is gonna be the first time I will try to network my comp without using a router. I'm currently learning FreeBSD and would like to use it as my firewall. We have 4 computers in our house and it's all connected to router. What I would like to learn/know is the stuff I need to network all 4 computers without using a router.
I want all 3 computers to depend on my freebsd box. How do I accomplish that? I'm not asking to spoon feed me with setup. What I wanna know is what hardwares do I need in order to accomplish that? Do I need a 4 port
PCI network card on my freebsd box? could I use 2 routers at the same time? What hardware do I need to network? Thanks

I just made everything seem confusing but hopefully someone will understand what i'm talking about.

I'm not to experienced with FreeBSD, or linux but for the networking part I believe that all you would need would be a 4 port switch or hub, then configure all your computers to go through the BSD box for there internet connection. I'm not sure if FreeBSD has some type of proxy built into it but you could set up the BSD box as a gateway for the other computers.

So I believe all you need is NIC cards in all your machines and either the switch or hub.

i've never done networking before or even read about it but I will ones I get some ideas.

Could I use 2 routers? like
router ~> freebsd with router card ~> 3 computer

or

router ~> freebsd ~> 4 port switch/hub ~> 3 computer

could I set it up like that? I want all the computer to have internet access. I wanna practise/try to secure my little network. My brother in law doesn't want to connect on freebsd box. He demanded that he just wants to be connected on the router that's why I'm asking this weird questions because I wanna set up my own little network without intereferring with his windows XP box.

Thanks for the reply :)

I don't believe you could hook the two routers together.

What you could do if you have two routers is set one up just for your brother so he can connect directly through that, then have the other router to use as a hub. Most every router out there has a wan port on it which I'm sure you know is for connecting to the iternet. Now what you do is don't plug anything into the wan port, just plug all your computers into the regular ports on the router. Then like I said just configre your FreeBSD computer to act as a gateway for your other computers.


OF course I guess you could always just configure your computers with permanent IP's on you network then configure the router to send all information to the net from your computers throught the BSD box first, then configure it to just directly route your brothers information straight to the net without going through the BSD Box.