iptables + routing public subnet to private interface. (Newbee)

[Bruno Wolff III]

On Thu, Jul 13, 2006 at 08:49:05 +0200,
  Gregory Machin <gregory.machin at gmail.com> wrote:
> The box is acting as the router. we have a cat 5 cable from it into our
> isp's noc. and there is no budget to get a router. I'm sure it can be done
> with afew lines of iptables ???

You don't need iptables to do routing. You pretty much just need to make
sure forwarding is turned on.

You might use iptables to do NAT if you don't have as many IP addresses
as machines. This only takes a couple of rules to do.

You might use iptables to do packet filtering as a security measure.
This is normally not that complicated, but can easily be dozens of rules.