On Mon, 13 Dec 2004 02:55:39 -0600, John Reese <jwreese0 at comcast.net> wrote:
> I work for a company that has nearly exhausted its Class C range of IP
> addresses. We decided to get by the problem by using a single Linux
> router running iptables to route the exhausted 192.168.1.0 network
> (eth0) to three LANs with numbers 192.168.101.0, 192.168.102.0, and
> 192.168.103.0 (eth1, eth2, and eth3). Our goal is to have clients inside
> those networks see a single server in the old 192.168.1.0 network.
> 
> Since the new LANs are inside the production network (192.168.1.0), they
> face a trusted network and don't need to filter or firewall transactions
> across the router. The clients only need to see the server, and the
> server needs to see inside the new LANs in order to print to their
> printers.
[snip for brevity]

I don't think you want to use NAT at all, since that is going to
effectively masquerade your IP addresses. If you just use your Linux
box as a router without NAT, a few static routes should give you
everything you need. I don't recall the syntax off-hand, but you
should be able to setup simple rules in your server so that for the
networks 192.168.101.0/255.255.255.0, 192.168.102.0/255.255.255.0, and
192.168.103.0/255.255.255.0, it should use your internal router
instead of its default gateway.

On the router, simply set all incoming traffic on 192.168.1.0, bound
for one of the other three networks, to go out the appropriate
interface.

Hope this helps, I know it might be a bit vague.

-- 
Dave Sherman
MCSA, MCSE, CCNA
[Insert witty .sig here.]

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