Linux - NetworkingThis forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.
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I'm trying to forward SSH connections in my LAN from one computer to another using iptables, however, I'm stuck. Yet, I think I'm just about there, if someone could give me a small hand here.
At the moment my internet comes into my flat and is then routed with a linksys router. This has an external IP, and a private one (10.0.0.1). At the moment, my server is set up as a DMZ, and any SSH requests to my flat are sent straight to my server.
Instead, I would like SSH requests to be routed (using iptables) by my server and sent to another computer.
My server has two cards: eth0 10.0.0.2 and eth1 192.168.0.1 . The other computer (call it COMP3) has IP eth0: 192.168.0.1.
At the moment my server and COMP3 can chat to each other (ie they can ping one another, and I can SSH in from one to the other.
I would like that, whenever I SSH to my flat the Linksys router sends the request to my server, and then my server says "oh, this is an SSH request, I ad better send it to COMP3".
So far, Ihave a working firewall on my server (which allows SSH requests) and no firewall on COMP3. The rules which I have written to allow this forwarding are:
if u want to share internet for your computer behind linux also, u may want to visit www.iptables-script.dk to generate iptables script for yourself. it is simple and secure enough.
i hope it will help u.
You should not need SNAT, Masquerade, or POSTROUTING rules. If you want to forward port 1234 to 22, change --dport 22 to --dport 1234 in the PREROUTING rule. You did setup the linksys to forward anything for port 1234 to 10.0.0.2, correct?
If you still can't get connected, here is a very basic ruleset that will forward 1234 to 192.168.0.2:22. It should work, if it doesn't the problem is something else.
The second rule works because it will allow any tcp packet to be forwarded to any ip, using any port, on any interface. The first rule allows all tcp packets to be forwarded to 192.168.0.2, but will not allow them to be forwarded back to the internet, so a connection cannot be established. I would use a few rules like this.