I have a problem related to Transmission torrent client. Specifically on a Fedora 23 Linux distribution.
My goal is to increase download speed and surfing on the internet. I found out the best way to do it was port forwarding.
I followed online guides and tried to do it manually via the router page, accessed through the IP address. Then I did the same using the firewall GUI app you can download through the software manager. However, doing the test from preferences in Transmission, the result is always "port closed".
The firewall GUI is called Firewall Configuration, which I assume just modifies my personal firewall on my Fedora.
I'm forwarding on port 51413, transmission default port, to the same on the standard IP I got from my router page online. The router is not my Fedora box, but an external TP link modem.
I tried disabling the firewall, specifically FirewallD on Fedora, but nothing changed.
EDIT: SOLVED
i finally solved: apparently transmission had a problem with the option "use UPnP or NAT-PMP port forwarding from my router" , which automatically fowarded port 51413 on the router. disabling the option and forwarding manually another port worked.
Best Answer
You need to work at two levels, computer and modem router: