Torrents

Adding

  • When Automatically add torrents from is enabled, Transmission will watch for .torrent files to be placed in the specified directory. When it finds new torrents there, it will automatically load them into Transmission. This can be useful when downloading .torrent files from a separate application, such using FlexGet for RSS feeds.
  • When Show options dialog is enabled, Transmission will display the options dialog when adding torrents to give you a chance to specify which files in the torrent to download, which directory to save the files in, and so on. If this feature is disabled, Transmission will use skip the dialog and default settings instead.
  • When Start when added is enabled, Transmission will try to start downloading torrents when they are added. Otherwise, they will be added in a paused state.
  • When Move .torrent file to the trash is enabled, the .torrent file given to Transmission will be moved to the system trashcan if the torrent is successfully added. If you think you may need to remove and then add the torrent later, do not select this option unless you are sure you can download the same .torrent file again.

Downloading

  • If Append .part to incomplete files' names is enabled, files will have the ".part" suffix until they are finished downloading.
  • Save to Location is the default download directory that is used if "Show options dialog" is disabled.
  • When Keep incomplete torrents in is enabled, newly-added torrents will be stored in the specified directory until they are finished downloading. When they finish downloading, they will be moved from there to the "Save to Location" folder.
  • If Call script when torrent is completed is enabled, a user-specified script will be invoked by Transmission once per torrent when the torrent is finished downloading, after the ".part" suffixes are removed and the files have been moved into the "Save to Location" folder. The Transmission wiki has more information about these scripts.

Seeding

  • If Stop seeding at ratio is enabled, a seeding torrent will be stopped when it reaches the specified upload ratio.
  • If Stop seeding if idle for N minutes is enabled, a seeding torrent will be stopped if it is idle for at least N minutes.

Speed

Speed Limits

  • If Limit download speed is enabled, Transmission will limit session-wide download speeds to this speed, with one exception: you can set specific torrents to ignore the session-wide limit in Torrent > Properties > Options
  • If Limit upload speed is enabled, Transmission will limit session-wide upload speeds to this speed, with one exception: you can set specific torrents to ignore the session-wide limit in Torrent > Properties > Options

Temporary Speed Limits

Temporary speed limits -- often called "turtle mode" -- are a second set of upload and download limits that can be set to run on a schedule and can also be toggled manually. Scheduled use is helpful if your ISP has different bandwidth caps on evenings or weekends. Manual use is helpful as a single-click way to quickly give other applications more bandwidth. You can toggle turtle mode manually by clicking the turtle button in the lower left corner of Transmission's main window.

  • The Temporary download speed is the download speed limit enforced when turtle mode is active.
  • The Temporary upload speed is the upload speed limit enforced when turtle mode is active.
  • With Scheduled times, you can tell Transmission when to automatically enable and disable turtle mode.

Privacy

Blocklist

  • A Blocklist is third-party list of peer addresses to block. This can be used to block peers whose addresses are believed to belong to spyware or malware manufacturers.

    The Transmission Project does not evaluate or endorse any specific blocklists. If you do not know what blocklist to use, you might read about some third-party blocklists and evaluate them on your own.

  • If Enable automatic updates is enabled, Transmission will periodically refresh its copy of your blocklist from your specified URL.

    Transmission's wiki has more information on blocklists.

Privacy

  • Encryption mode refers to BitTorrent Protocol Encryption which can be used to improve privacy. Encryption can cause a higher CPU load on older or underpowered systems.
  • PEX, or Peer EXchange is for sharing peer lists with your connected peers. If you've already got one peer, this can be used to find more peers quickly.
  • DHT, or Dynamic Hash Table, is another peer-finding tool. Although sometimes slower than other methods, DHT can be extremely good at finding peers even where PEX, LPD, and trackers all fail.

    DHT uses a Gnutella-style distributed network to find peers for you. This means your IP address and your torrent's hashcode will be passed around the distributed network in search of a match. Some people consider this to be a privacy hole and leave DHT turned off.

  • LPD, or Local Peer Discovery, is a mechanism for quickly finding other BitTorrent peers on your local network.

Network

Incoming Peers

    If you use a router to connect your computer to the internet, you probably need to set up port forwarding on that router so that other peers will be able to connect to you. If Use UPnP or NAT-PMP is enabled, Transmission will try to do this for you automatically.

    Test Port asks transmissionbt.com to test connecting to your computer as peers would. "Port is open" means that it succeeded; "Port is closed" means it failed. If the test fails, you might check your port forwarding settings on your router and your OS' filewall rules. See this page for more information.

    Pick a random port is a suggested privacy feature since it will make your open port harder to guess. However, because it makes life understandably hard for some firewall systems, it is disabled by default.

    Transmission will try to use those two standard protocols (via the third-party libraries libnatpmp and miniupnpc) to tell your router to pass incoming connections on the right port along to your computer. This, again, is so that external BitTorrent peers can initiate a connection with you.

Limits

  • Maximum peers per torrent and Maximum peers overall limit how many peers Transmission will allow to stay connected.

    These two settings are often misunderstood -- and were left out of earlier versions of Transmission for that reason -- but they can be useful if your router can not keep up with the demands of p2p. If that happens, try lowering these numbers.

    Some users mistakenly think the higher these values are, the higher their speeds will be. This can be true under some circumstances, but you can also overload your router and/or waste bandwidth on keeping communications open with too many peers. As a general rule of thumb when editing these fields, use the smallest numbers that still reach your desired speeds.


Desktop Integration

Desktop

  • Inhibit hibernation when torrents are active will stop your desktop from hibernating for as long as you have active uploads or downloads.
  • Show Transmission icon in the notification area -- your mileage may vary on this feature. Ubuntu's desktop has deprecated the notification area favor of in its own application indicator, and GNOME 3 is apparently also deprecating the notification area in Gnome-Shell.
  • Show popup notifications will pop up a notification when a torrent has been added without manual intervention (such as from a watch folder) and also when a torrent finishes downloading.
  • Play sounds when downloads are complete plays the system's "download complete" sound when a torrent finishes downloading. This is, perhaps, a lightweight feature -- but the appeal of hearing your computer "ding!" from down the hall is undeinable. :)

Web

Web Client

  • When the Web Client is enabled, Transmission will start up a very small web server on your computer at the specified listening port. You can use this to access your home Transmission session through a web browser when you are not at home. For security, you can enable username and password authentication or an IP whitelist to prevent unauthorized access.

    Over time, more third-party remote control applications have been written that use this feature. There are remote controls for Windows, for iPhones, for Android phones, curses-based terminal ones, and many more. See this page for links.