IPtables help needed. Simple port redirect

[Johnnytoxic]

I cannot seem to find anywhere that describes how to do a simple port redirect on a linux box using iptables.

I don't want it going to another ip address, I just want the port to be locally redirected. I ended up with this which im not sure about...

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 5000 -j REDIRECT --to-port 8000

Would this mean anything incoming on 5000 gets redirected to 8000 on the local machine? Is there anyway to check if this is working correct.

Please help. Thanks.

 

[dave-lew99]

iptables -t nat -A PREROUTING -p tcp -m tcp -i eth0 --dport 5000 -j DNAT --to-destination 127.0.0.1:8000

Is probably more likely (or rather, that's the way i'd do it) you can use tcpdump -i lo port 8000 to see if localhost:8000 is getting packets when you access system:5000