How to open a port such that a torrent client can both be used on Ethernet and Wi-FI connection?

Question

From previous questions/answers I understand that forwarding one certain port to two different IP addresses is not possible.

I have a laptop that connects through the router to the internet. When it's on Wi-Fi it gets a different internal IP than when it's using the Ethernet cable.

My torrent client (Transmission) requires that a certain port is opened and forwarded to the machine. Problem is, I can only forward the port to either the Ethernet interface, or the Wi-Fi interface. I would like to somehow switch from one network interface to the other without interrupting my torrent client. How can I achieve this?

Answer 1

I don't think you can forward the SAME port to 2 IP addresses (without spoofing the MAC which could lead to problems, as discussed above).

One solution would be to turn on uPNP on both the router and the torrent client, which automatically forwards ports for you. (delete the manual forward)

Answer 2

Using your operating system, if you set the IP address (e.g. 192.168.1.2), subnet mask (e.g. 255.255.255.0), default gateway (e.g. 192.168.1.1) and DNS (e.g. 192.168.1.1 or 8.8.8.8) manually on both the PC LAN and Wifi Interfaces, the router will be forced to talk to your PC using that IP address, regardless whether you are using the LAN or Wifi. Just make sure you do not connect both at the same time.

Answer 3

In some routers you can assign an IP to a MAC address (I believe you can do that for two as well).

So forward the port to that IP, and save that IP for both your ethernet MAC address and your wifi MAC address. On a second hand, my router doesn't allow me to do that so perhaps it isn't possible...

I've got it! Ubuntu lets you fake your MAC address, so perhaps you can do that to have the same MAC address for both the wifi and the ethernet interface!

Then just add a static IP for that address

And finally forward to that IP.

You might not be an ubuntu user, but if you can do it there, you can probably do it everywhere else.