Here is the situation:
* I have an ADSL modem which has an ethernet port.
* You can put an IP in that eth port.
* You can also put Network Address Translation (NAT) in that modem.
So, in current usage, I set the eth ip address 10.0.0.1 (255.0.0.0), and it connected to a HUB.
In the local area network (LAN), every machine will use 10.0.0.1 as the gateway.
I run several servers also in the LAN, e.g. mail server, imap, pop3, and web.
I setup all necessary NAT rules for all those servers in the modem. This works fine before.
The problem is, for some strange reason, the NAT disappeared! This happened several times.
Now, I plan to move those NAT in a linux box using iptables.
I will install a linux box with 2 network card :
- eth 0 --> 10.0.0.2 (255.0.0.0)
- eth 1 --> 192.168.0.0 (255.255.255.0)
I will connect modem:eth with linux:eth0, using cross over cable.
I will delete all NAT in the modem.
But then I dont know the rest, I meant how should I configure the NAT in the linux box?
Will this plan work? Should I setup any gateway in the modem pointed to the linux box?
Please help me.