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Old 07-30-2004, 10:21 PM   #1
musicman_ace
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IP forwarding from eth0 to eth1


I thought I had this working, but I guess not.

The backgroud information:
ETH0 is a gigabit card for the internal network.
ETH1 is a 10/100 for the Internet connection to be shared

For whatever reason, when I installed linux, the first ethernet card was assigned ETH1 and the second was ETH0. IP_FORWARD does have a value of 1, but it isn't forwarding traffic.

Is this because ETH0 should be the ISP assigned address and not the other way around?
Is there a way to switch the NICs value so that ETH0 is the 10/100? Would that help?

Any suggestions if I'm on the wrong track with my questions.
Thanks everyone
 
Old 07-31-2004, 12:25 AM   #2
Mortus Canis
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I too had the same problem a few days ago!

There shouldn't be a problem having eth1 go to your isp, just check /sbin/route to make sure that your routing table is set up right.

To get IP Forwarding to start working, you need to set up some rules in iptables that implement NAT. I grabbed the latest rc.firewall script from http://www.ecst.csuchico.edu/~dranch...masq/examples/ and it started working, now I am customizing that script for my network.

Let us know where that takes you.
 
Old 07-31-2004, 01:37 AM   #3
DavidPhillips
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The name of the device has nothing to do with it. What is the problem?

Are you trying to do NAT or do you want a bridge?
 
Old 07-31-2004, 09:54 PM   #4
musicman_ace
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Trying to share an Internet connection with the home network. I used the same firewall I've used before which had NAT working perfectly, but I switched the ETH0 and ETH1 cause the other machine was setup so that ETH0 was the Internet

I'm going to check into the ideas above to see if that helps.
 
Old 07-31-2004, 10:56 PM   #5
michaelk
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Check the routing with the route command. Is the gateway configured for eth1.

Of course verify your firewall script has the internal as eth0 and the external as eth1
 
Old 08-01-2004, 04:39 AM   #6
DavidPhillips
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If the problem is the default route you may need to setup the internet interface as the primary in the ifcfg-eth? file.
 
  


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