Download your favorite Linux distribution at LQ ISO.
Go Back > Forums > Linux Forums > Linux - Networking
User Name
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.


  Search this Thread
Old 03-27-2004, 06:06 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, 05:00 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, 09:55 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, 09:41 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...


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Wireless network on eth1 diabled Ethernet eth0 and eth0 never comes back tadatoshi Linux - Wireless Networking 4 09-23-2004 05:57 PM
Firewall WAN eth0 LAN eth1 self-bridges, eth0 does all routeing. Nichole_knc Linux - Networking 5 07-29-2004 02:33 PM
Routing between eth1 and eth1:1 cli_man Linux - Networking 3 04-05-2004 11:54 AM
eth1 added, mysql connections FROM this machine are from eth1. Need bound to eth0??? kreese Linux - Networking 9 03-31-2004 12:12 PM
Kernel 2.4.22 finds eth0 and eth1 but 2.6.0 does not find eth1 coollink Linux - Networking 3 01-13-2004 07:32 PM > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 02:07 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration