Networking – Why the Port Forwarding rule is not working

Some routers don't like it when you try to access an internal computer (i.e. your DVR) using the external IP from within the network. Get a friend to test, or use a smartphone or a neighbours open WiFi to test.

Automatic - UPnP Service

You can forward the port using UPnP Service (see update 1 and 2 above). This is not really what I want, since I only need to forward a single port (OK, two ports at most). But I'll post a small step by step guide here in case someone else finds it useful.

In uTorrent...

1. Open uTorrent.
2. Go to Options, then Preferences, and click Connection.
3. Make sure Enable UPnP port mapping is enabled.
4. Make sure Enable NAT-PMP port mapping is enabled.
5. Make sure Add Windows Firewall exception is enabled.
6. Make sure Randomize port each start is disabled.
7. Note down the port number (i.e. 31090) and click OK.

In DD-WRT settings...

1. Open the DD-WRT interface (in my case 192.168.0.1) in a web browser.
2. Navigate to NAT/QoS, UPnP.
3. Set UPnP Service and Clear port forwards at startup to Enable and click Apply Settings.
4. Navigate to Administration, Management, and click on Reboot Router.

Start uTorrent and wait a few minutes. If you have the NAT page open in the router interface you will see when the uTorrent port is successfully forwarded. You can then try running the port test in uTorrent.

(Edit: The built-in port tester in uTorrent is not reliable, as we have concluded above. Use an external resource like a web based port tester, such as yougetsignal.com.)

Manual - Port Forwarding

Follow the steps above for uTorrent. Then continue with the steps below.

In DD-WRT settings...

1. Open the DD-WRT interface in a web browser.
2. Navigate to NAT/QoS, UPnP and make sure the UPnP Service is set to Disable.
3. Click on Save, and then Apply Settings.
4. Navigate to NAT/QoS, UPnP, Port Forwarding.
5. Click on Add button to add a new empty line.
6. Type in a name for the rule under Application. This can be anything.
7. Select TCP or UDP as Protocol, or select Both.
8. Leave the Source Net field blank (unless you have a reason not to).
9. Type the port you want to open in the Port from field (remote port).
10. Enter the IP Address of the computer you want to forward traffic to.
11. Type the port you want to use on the target machine (local port). You can use the same port.
12. Check the Enable box and click Save.
13. If you need to open more than one port, repeat steps 5 - 12, otherwise go to the next step.
14. Click on Apply Settings.
15. When you're done adding new ports, navigate to Administration, Management and click on Reboot router.