What is Port Forwarding?
If you are connected to the internet via a router, or have a firewall running, port forwarding is the act of opening a port in the firewall/router so that incoming connections from the outside world can be made with your computer.
Why do I need to Port Forward?
Transmission uses a single port for all the torrents you are downloading. If the port has not been opened (ie forwarded) that means only you can make connections to others in the swawm. If the port is forwarded, others can connect to you, thus increasing the potential number of people connected to you, and more importantly increasing the speed of your download.
How do I Port Forward?
The process is fairly straightforward.
If your modem is directly connected to your computer, and you have the OS X firewall running (which is highly recommended in this case), you'll need to open a port in the firewall.
For instructions click here.
If your modem is connected to your computer via a router (wired/wireless) you'll need to open a port in the router.
For instructions click here.
How do I know if i've done it right?
- Open Transmission.
- Go to this website, https://www.grc.com/x/portprobe=50001 Replace the '50001' bit of the URL with what ever port you have forwarded.
- If you get 'Stealth' or 'Closed' then you haven't forwarded correctly.
- If you get 'Open' then you have successfully port forwarded!
What is a static IP?
Where your computer is assigned an IP address which does not change. This can be helpful if you have a laptop or have multiple computers on your network. While it makes things a bit simpler, you don't have to have a static IP for BitTorrent or Port Forwarding to work.
A dynamic IP address assigned by your wireless router for example will most likely not change unless you reboot your computer, or leave and rejoin the network. Thus, having a static IP isn't really necessary and most people should be alright with a dynamic one.
How do I get a static IP address?
- Go to System Prefs >> Network, double-click on your connection (for instance, Built-in Ethernet), and click the TCP/IP tab.
- Write down the IP, Subnet Mask and Router addresses.
- Go to your router 'status' page via your web browser (Airport Admin Utility if you are using an Airport BS), and write down the DNS Server addresses. Alternatively, you can enter your router's internal IP (e.g. 192.168.0.1). This is sometimes quicker, as it refers to the router instead of the server.
- Then, return to the TCP/IP page in System Prefs.
- Choose "Manually" from the Configure IPv4 drop down menu.
- Enter the IP address you wish to have, eg 192.168.0.100, or 10.0.1.100. It should be of a similar format to the IP address you found in step 2, with only the last number changing.
NB: You cannot have a static IP address that's within the DHCP range. Thus it is recommended that you make the last digit of your address large enough to discount this possibility, like we have done in our examples. - Fill in the other boxes using the addresses you wrote down in steps 2 and 3.
- Click 'Apply Now'.