I'm on Kubuntu, Firefox 3.5.
You're on Firefox 3.5, right? Then Sathya's solution is wrong.
According to the site he linked, the flag you must create shall be called
not network.protocol-handler.*external.*magnet, as he suggested.
Besides, you can initialize it to false and thus Firefox will ask you the program which you want to use. I just did it and it worked - no need to restart Firefox.
If KTorrent won't support Magnet Links, you might try qBittorrent, which I'm using succesfully.
about:config into the address bar and press Enter.
Next, Add a key by Right-click -> New -> Boolean -> Name:
with value -> true
Add another key, by Right-click -> New -> String -> Name:
network.protocol-handler.app.magnet with Value -> ktorrent
Also, do ensure that the key
network.protocol-handler.expose-all is set to true.
From Mozilla KB
This worked for me, FF 47, Debian 9, KDE 5:
1. In about:config find "network.protocol-handler.expose-all", change to "false"; 2. Click on some magnet link - a file browser pop-up should appear, show it full path to the executable (/usr/bin/qbittorrent for ex.); 3. Change "network.protocol-handler.expose-all" back to "true"; 4. Download the world.
ktorrent does not support uri links, by the way. http://ktorrent.org/wiki/index.php/FAQ#Does_KTorrent_support_magnet_links.3F i myself followed the sathya suggestion and i've had the same issue as you, obvio171. i'm running archlinux firefox 3.5.5-1 should we file a bug?
I was using gentoo + Firefox 19. When I had the problem, adding stuff to 'about:config' won't help and I don't see "Magnet" under Preference -> Applications. Eventually I found the problem and it may have something to do with the KDE mime type configurations.
I changed /usr/share/applications/kde4/ktorrent.desktop by appending: x-scheme-handler/magnet; to 'MimeType=xxx'
Then I edited ~/.local/share/applications/mimeapps.list by inserting the line: x-scheme-handler/magnet=kde4-ktorrent.desktop
Then, if I click on an magnet link, firefox will pop up a dialog asking what application to use instead of saying not understanding protocol. After the pop up, you need to select ktorrent's binary (/usr/bin/ktorrent on my computer).