Hola,

Mental note: Don't drink 2 glasses of Coke at 8:30pm on a 'school
night',  Switch to Sprite.

Here is a NetBSD howto link for seting up a private network.  While
there are some NetBSDisms specific only to that OS the underling
principals are the same.  e.g. you may have to edit different config
files.  These documents really helped me get my head around the concepts
when I was first starting out.  So don't follow these instructions step
by step and expect your network to work under linux 'cause it probably
won't. [you have been warned].  Instead I'm sure the linux documentation
project has some specific instructions about networking,  Or failing
that the book that came with your distribution will surely instruct you
on the ins and outs of seting up a private network with your distro.

NetBSD Networking howto:

http://www.macbsd.com/macbsd/howto/net-howto.html

There was some queries about a firewall discussion.  Here is one place
to start. I'm sure there are others.

http://www.fwtk.org/main.html

Instructions for installing & config-ing come with the download.  There
are good trouble shooting FAQs on the above web site.

Good luck,

Jerry