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Old 03-27-2004, 07:06 PM   #1
Registered: Nov 2003
Distribution: Redhat 9
Posts: 38

Rep: Reputation: 15
Internal Routing eth1 to eth0

I have 2 NICs in my machine.
1 is eth0 and is assigned the IPs (eth0) and (eth0:0)
the other 1 is eth1 assigned the IPs (eth1) and 82.133.***.*** (eth0:0 - masked)

I have NAT configureed and working.

the assignment of 82.133.***.*** is simply so that when l goto my external IP from another machine on my LAN , it actually gets somewhere (my Router, a zoom X3, drops outgoing conenctions to the WAN ip)

The router has set as a DMZ. (so eth1 is used for anything related to the external IP and eth0 is the internal LAN)

I have setup some portforwards so that or 82.133.***.***:80 get redirected to

This workd for internal Clients and external clients, but not for the box itself - when i try to telnet to port 80 (or other ports) I get "connection refused"

I would like to do 2 things:

1) Setup iptables so that going to any assigned ip on eth1 gets redirected to ( => | => | 82.133.***.***:92 => | 82.133.***.***:98 => unless there is another rule pointing it elsewhere.

2) I would like the box to obey the port forwardings I have put inplace so that it can telnet to 82.133.***.*** and reach the httpd listening on
( to setup a portforwading I use the rules:

iptables -A PREROUTING -t nat -i eth1 -p tcp --dport <port> -j DNAT --to <Host IP>:<Port>
iptables -A PREROUTING -t nat -d 82.133.***.*** -p tcp --dport <port> -j DNAT --to <Host IP>:<Port>
iptables -t nat -A POSTROUTING --dst <Host IP> -p tcp --dport <port> -j SNAT --to-source 82.133.***.***

If you need any more information, Please ask.
Old 03-28-2004, 06:00 AM   #2
Registered: Dec 2003
Location: Australia
Distribution: Mandrake 9.2
Posts: 151

Rep: Reputation: 30
why are you doing all that bull shit when u can simply use 1 nic and a hub
Old 03-28-2004, 10:55 AM   #3
Registered: Nov 2003
Distribution: Redhat 9
Posts: 38

Original Poster
Rep: Reputation: 15
erm, maybe becuase i want to be able to actually connect to my external ip? doing it this way

a) makes my shite router give all port authority to for me to add port forwards
b) allows me to visit http://82.133.***.*** and get something other then connection refused like i used to...

I've got it all working as i want - aprt from the box itself doesn't obey the port forwardings like i want it to....

I don't need any smart comments, this way works.
Old 04-02-2004, 10:41 AM   #4
Registered: Nov 2003
Distribution: Redhat 9
Posts: 38

Original Poster
Rep: Reputation: 15
so i guess its not possible, Linux refuses to route connections by itself according to iptables rules...


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