Portforwarding a Router
In this case, it is probably OK to disable the OS X firewall, as you are already being protected by the router. To disable the firewall, open System Prefs >> Sharing >> Firewall. Click Stop.
- Find out what your IP address is. You can find your computer's IP address by going to System Prefs >> Network, double-clicking on your connection (for instance, Built-in Ethernet), and clicking the TCP/IP tab. It's probably something like 192.168.1.100, or 10.0.1.2.
- Open Transmission, go to preferences, and enter a number for the port. It is recommended you pick a random number between 49152 and 65535. Let's use 50001 for now. Then quit Transmission.
- Go into your router configuration screen. Normally this is done via your web browser using the address 192.168.0.1 etc.
NB: Apple's Airport uses an application called 'Airport Admin Utility' to configure it. - Find the port forwarding (sometimes called port mapping) screen. While the page will be different for each router generally you will enter something similar to the following:
- For 'Application' type 'Trans'.
- For 'Start Port' and 'End port' type 50001.
- For Protocol, choose Both.
- For IP address, type in your IP address you found in Step 1.
- Check Enable.
- Click save settings.
For more comprehensive instructions specific to your router, click here and choose your router from the list.