IP Forwarding Issue

[menonrr at adelphia.net]

Hello,

I am a fairly new person in Linux networking.

The issue I got some responses was as follows:
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I have had some good help to enable IP forwarding on my Redhat 9 
gateway with the rule:

[CODE]iptables -t nat -A POSTROUTING -o eth1 -j SNAT --to-source 172.16.3.10[/CODE] 

This rule forwards the traffic from the internal network (172.16.4.0/24) to the 
outside trhough the NIC with IP address 172.16.3.10.

Problem:

But I feel that the internal IPs are being forwarded with the IP address of the 
external NIC of the gateway.

It would be helpful if I could have a way to keep the internal IP address 
(172.16.4.0)as it is without being substituted with the gateways IP 
address(172.16.3.10). This is because I want the external users to see the 
internal machines(172.16.4.0 network) as it is.

Please advise.


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Adding to my question above:-

The redhat 9 gateway forwards traffic between two private networks. The network topology goes like this:

172.16.8.0/24 ------------ router ----------- 172.16.3.0/24 ------- Redaht 9 ------- 172.16.4.0/24

Is there a way that folks from the 172.16.8 network see the 172.16.4 network machines as they are, without 
being substituted with the redhat 9 gateway IP of 172.16.3.10 ?

This is a strictly private network setup for doing some tests.

Thank You.