Before I waste anyone's time, I am assuming the following (if you don't have all these requirements met, do them before proceeding):
1. All the physical networking gear, with green link lights on both Network Cards and Hubs.
2. You have just installed Redhat 6.x on your system. If not, go here (http://www.linuxiso.org/redhat.html) and here (http://www.ibiblio.org/mdw/HOWTO/Installation-HOWTO/index.html).
3. You have setup your modem, and configured to an ISP (hopefully using WvDial). If not, go here (http://www.ibiblio.org/mdw/HOWTO/ISP-Hookup-HOWTO.html).
4. Linux and Windows acknowledges your cards. If not, go here (http://www.ibiblio.org/mdw/HOWTO/Ethernet-HOWTO.html) and here (http://www.ibiblio.org/mdw/HOWTO/Net-HOWTO/index.html). You might also consider buying new cards if you just *cannot* get the ones you have working. Some are just not linux compatible.
If you are *not* planning to have a super high-traffic network, I recommend the following for starters:
10mpbs hubs - I have found 8-port hubs for USD$26.00 dollars a piece, or 4-port hubs for USD$15.00
10/100mpbs network cards - I have found Encore 10/100 Fast NIC's just because they are (as of 11/1/2000) USD$8.00 a piece, and Linux (and Windows) auto-detects them flawlessly. (as a side note: 10/100 is 'more than enough' for 10mbps hubs, but I haven't been able to find 10mbps network cards under 8 dollars a piece that work flawlessly in Linux.)
As for wiring, I recommend you going down to your local computer store and buying it, after you have measured out how much you want. Tell them you are setting up a home network using an ethernet toplogy, and would like CAT5 cable, they should be able to help you from there.
Once you have met these conditions, we first need to make sure we have all the programs, so here are the links to all the programs we will be using:
DHCPd (112k) (The server side.. http://rpmfind.net/linux/RPM/contrib/libc6/i386////dhcpd-2.0b1pl0-1.i386.html)
http://www.internet.junkbuster.com/ijb20.tar.Z
PMFirewall (59k) (Current is 1.1.4 upon writing this.. http://www.pmfirewall.com/PMFirewall/#download)
Portsentry (43k) (Current is 1.0 upon writing this.. http://www.psionic.com/abacus/portsentry/)