forward ports with iptables

timgerr · 08-29-2008, 12:43 AM

Hello all,
I am in need of some help. When a request comes into my server on port 80, I would like the request to be forward to port 5223. When the information leaves the server via 5223 I would like it to go out port 80. Can someone show me in iptable speak what that looks like?

Thanks,
timgerr

Berhanie · 08-29-2008, 03:31 PM

It would be something like this. The reverse direction is handled automatically.

Code:

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j DNAT --to-destination :5223

fberbert · 08-29-2008, 05:14 PM

In addition, if the origin packet comes from the destination server (what I consider improbable), you can try:

iptables -t nat -A OUTPUT -i eth0 -p tcp --dport 5223 -j DNAT --to-destination :80

I often use this rule to access my remove ssh server, that runs on port 22022:

iptables -t nat -A OUTPUT -p tcp -m tcp -d my.remote.host --dport 22 -j DNAT --to my.remove.host:22022

So I can just type:

ssh my.remote.host

Instead of:

ssh -p 22022 my.remote.host