Thursday, April 14, 2011

Port Forwarding

The post is more for my own remembering than anything else, although I'm posting it here just in case someone stumbles across it and finds it useful

The goal: allow a remote computer to view a website hosted on my local computer.
  1. Set up an account with
  2. Install ddclient on my Ubuntu machine to periodically notify what my IP address is
    1. Don't prepend "http://" to your domain name in the ddclient setup!
  3. On my router, assign my computer a static IP address
  4. On my router, forward incoming traffic on port 8080 to the new static IP address
  5. On my computer, port-forward port 8080 to port 80, where my apache webserver is listening
    1. sudo iptables -t nat -A PREROUTING -p tcp --dport 8080 -j REDIRECT --to-port 80 (add the port forwarding rule)
    2. sudo iptables -F (flush the rule)
    3. sudo iptables -t nat --list (view the rule)
    4. sudo bash -c "iptables-save < /etc/iptables.rules" (save the rule to a file)
    5. sudo echo -e '#!/bin/sh\niptables-restore < /etc/iptables.rules\nexit 0' > /etc/network/if-pre-up.d/iptablesload (to create a script to restore the iptable rules every time the network interface comes up)
    6. sudo chmod +x /etc/network/if-pre-up.d/iptablesload (to make the script executable)
  6. Visit my site in a browser at


Anna Marie said...

Yes Ben, everyone knows how smart you are....(-;

The Writer said...

You know that's not why I posted it. :)

I spend half my working hours searching various forums and blogs for answers to random programming questions, so whenever I figure something out, I like giving back by posting a clear tutorial or example of how I solved the problem.

It's the ecosystem of the internet.