Home Networking

[Wes Bateman]

Andrew:

Everything, of course, depends on exactly what you're trying to do.  I
can't see where you'd need an additional router.  The cable "modem" is
really a router, of sorts (well more router than modem anyway :) ).

What many people do, and I'm guessing is what you're attempting, is build
a private network behind the linux firewall.  You'll need two NICs (at
least) in your Linux box.  One you'd connect directly to the cable modem
and the other you'd connect to your hub.  You'd configure your Linux box
with your static public IP or to use DHCP to obtain it from your cable
provider (is @home still what cox is using there?) on the interface
connected to the cable modem.  On the interface connected to the hub,
configure a static address.  You'll probably want to use a reserved
private address space like 192.168.1.0/24.  The address you give your
Linux box on that "private" interface will become the gateway address for
your internal boxes.

This whole thing assumes that you have only one public address that the
cable company gives you, and you want to share it with all your internal
network.

You'll then want to use iptables or ipchains to build your firewall
rules.  Additionaly, for the sharing of a single public IP described
above, you'll want to enable masquerading.  How to do this is pretty well
documented and you can search for documents on the web.  If you need
additional help with it, shoot me an email off list and I'll help you with
specific rules need be.

Again though, everything depends on what you're trying to accomplish :)

Good luck,

Wes

On Thu, 10 Jan 2002, Bruner, Andrew wrote:

> 
> I'm getting Cox@home and plan on using a Linux box as a firewall. Do I need
> to also configure it as a router? Should I just go out and buy a router? Do
> I need a router at all? I have an 8 port hub that I was planning on using in
> conjunction with the Linux box as a firewall. Will that work?
> Thanks for any comments.
> -Andrew