Cable Modem Setup

[Gene and Amy Dascher]

I am getting ready to have Comcast come out and install a cable modem at
my house. I have a p5-133 set up as my firewall/router.  I am running
RedHat 6.1 with ipchains for the basic firewall & IP masquerading.  Here
are a couple of questions I have about that whole process (and yes, I
have read most of the HOW-TOs out there):

1.  Do I Have to run a proxy server like squid to be able to access the
Internet from my Windows machines on the same network?  From what I can
make of the ipchains stuff, I don't need to, but I could be overlooking
something.

2.  From what I understand, all I have to do is set my default gateway
on my main user box (not the firewall) to the IP address of the firewall
(eth0 that points to the internal network), and the nameserver addresses
to the ones given to me by Comcast, and everything should work.  What I
can't see is where I tell ipchains to use eth1 (that is connected to the
cable modem) as the internet connection.

3.  What do I set as the gateway for eth0 on the firewall machine(or do
I need to set it to anything?)

Thanks,

Gene Dascher