NAT in Redhat 8.0

nerfherder64 · 10-07-2002, 08:06 PM

I have a cable modem and two Ethernet cards. eth0 is 192.168.0.1 and is connected to a hub, to which my other computer is also connected. Here are its settings:

Address: 196.168.0.1
Subnet Mask: 255.255.255.0
Default Gateway Address: 192.168.0.1

eth1 is connected to the cable modem and gets its IP address from DHCP.

The client computer is already set up correctly.

Now I can't seem to get NAT working to save my life. Can someone please tell me what I need to do? I've tried /sbin/iptables with various arguments, but nothing ever seems to get it working. I must be passing the wrong arguments somewhere along the way. I've searched Google a zillion times, and apparently nothing has been clear enough for me.

Thanks in advance.

mwjcox · 10-08-2002, 02:02 AM

It sounds like the same set up I have on my home network with a cable modem. I use the script from http://linuxselfhelp.com/HOWTO/IP-Ma...-examples.html web page. I put it into a file and make it excuteable, then run it. That should let all the computers run on the single modem.

nerfherder64 · 10-08-2002, 07:44 AM

Good example. Thanks.

Unfortunately, it's still not working. As it turns out, my computers aren't even seeing each other under Linux. They fail to ping each other. I tried resetting my hub, but that didn't help. They work fine under Windows XP (and Internet connection sharing works).

The client's IP (192.168.0.2) is set manually, not by DHCP. I can't imagine why RH won't see it (or vice versa). Any ideas?

Risc91 · 10-08-2002, 02:42 PM

are all of your computers within the same subnet? (e.g. 255.255.255.0)

nerfherder64 · 10-08-2002, 03:24 PM

Yes, the settings on the client computer are identical to those I listed for eth0 except for the IP address.

mwjcox · 10-09-2002, 06:15 PM

You have a dedicated nic for the local lan - properly 192.168.0.1 on the host. If you are using static (hard coded) IP address on the other computer, make sure the gateway is 192.168.0.1 on those computers with the same submask address (usually 255.255.255.0 ) .

I use hardcoded address on all the computers and I had to hardcode the DNS(Domain Name Server) on the client computer to make them work on the internet. You can get those addresses from the host computer that on the internet.

nerfherder64 · 10-09-2002, 10:40 PM

I've done all that. Unfortunately, a simple *ping* doesn't even produce any results. I don't understand it, since it all works under Windows. Oh well. I may just have to give up and buy a router. (It's either that or reboot into Windows whenever my wife wants to use the Internet.)