Does BitTorrent work in the background after quitting qBitTorrent

bittorrent

Recently I installed qBitTorrent so I could download some episodes of a Creative Commons-licensed TV series. I simply used apt-get install qbittorrent, ran qbittorrent, then added the torrent files, and pressed "start". I noticed that the series would take too long to download, so I quit qBitTorrent when it was at 10%. The next day, I launched qBitTorrent again, and was surprised to find the downloads complete. Either the 2.5 GBs downloaded within 3 seconds or something else occurred.

Does BitTorrent continue to exchange files after starting the download in qBitTorrent and then quitting qBitTorrent?

Best Answer

qBitTorrent has a mode where it is minimized in the notification area. If you go to the Options, then in the Behaviour tab, you will see a tree of checkboxes reading "Show qBit in notification area", and "Close qBit to notification area". This is the only way for qBittorrent to keep operating if you click the close button.

How to find the default application for a given mime type

# general case
xdg-mime query default <mime-type>

# your case
xdg-mime query default application/x-bittorrent
xdg-mime query default x-scheme-handler/magnet

Changing the default application

# general case
xdg-mime default <application.desktop> <mime-type>

# your case
xdg-mime default transmission-gtk.desktop application/x-bittorrent
xdg-mime default transmission-gtk.desktop x-scheme-handler/magnet

Those commands alter the file $HOME/.local/share/applications/mimeapps.list and/or $HOME/.local/share/applications/defaults.list, which means you can also do the change manually.

Does the Transmission use only TCP or also UDP

For this example, I launched Transmission to download Ubuntu 15.04 via BitTorrent protocol. Here is a quick way to see if there is some UDP involved:

maxime@maxime-laptop:~$ ps -e | grep transmission
 3167 ?        00:00:00 transmission-gt

maxime@maxime-laptop:~$ lsof -iUDP | grep 3167
transmiss 3167 maxime   17u  IPv4  58714      0t0  UDP *:51413 
transmiss 3167 maxime   18u  IPv4  58718      0t0  UDP maxime-laptop:42349->bbox.lan:5351

So yes, it looks like there is some UDP involved.

Now if you want to go further, you could capture and analyze the network data using a tool like Wireshark.

Editor's note:

I self-compiled Transmission 3.00, launched my VPN, opened both TCP and UDP ports for torrenting, results after a few minutes are clear, Transmission received 8 TCP packets, while at the same time frame 1673 UDP packets as documented by a snippet from iptables:

   8   448  ACCEPT  tcp  --  any  any  anywhere  anywhere  tcp dpt:<CENSORED>
1673  217K  ACCEPT  udp  --  any  any  anywhere  anywhere  udp dpt:<CENSORED>

Anyhow, another thing I found as proof of UDP action = trackers:

Best Answer

Related Solutions

How to Choose Default Bittorrent Client in Chromium

How to find the default application for a given mime type

Changing the default application

Does the Transmission use only TCP or also UDP