BitTorrent is a type of technology for the transmission of files over the internet. It has a wide range of purposes, including transmitting large files with little overhead.
What is BitTorrent?
BitTorrent is a type of Internet communications protocol that emphasizes peer-to-peer file sharing (P2P). Programmer Bram Cohen created the protocol in April 2001 and released the first version on July 2, 2001. On September 22, 2004, Bram partnered with Ashwin Navin to form BitTorrent, Inc.
BitTorrent is especially useful for transferring large files over the internet. It reduces server load and works more efficiently over networks with lower bandwidth.
The BitTorrent protocol works by letting users join a group of hosts called a “swarm.” The swarm means that users can upload to/download from everyone else simultaneously. This means that as you download a file, it splits up into smaller pieces. You download the parts from different users so that you can get the file quicker.
To send or receive files over the internet, you first need to download a BitTorrent client. This is a program that specifically implements the BitTorrent protocol.
How a BitTorrent Client Works
First, a computer joins a BitTorrent swarm by loading a .torrent file into the software. The client then contacts a special server called a tracker. A tracker keeps track of all of the connected computers to make sure they can connect to each other. Once your computer connects, the client downloads small pieces of the file and its data.
After a certain amount of data downloads, the client then starts uploading that data to other clients in the swarm. This means that everyone who downloads the same torrent is also uploading that torrent to everyone else. This ensures that the file downloads faster. This decentralization is what peer-to-peer means. Leechers are people who download from a swarm. Seeders are people that keep uploading the file after they finish downloading.
A torrent needs at least one seeder to become a viable download. Users cannot download a torrent that has zero seeders because no user has the complete file. The system inherently encourages people to seed. BitTorrent even rewards seeders by sending data to people who upload more than download. This speeds up download speeds for the swarm.
Trackers and Trackerless Torrents
A torrent tracker keeps track of ever client in a swarm and connects them with each other. Recently, trackerless torrents have become more popular. This means that BiTorrent clients can communicate with each other without a central server. Using this system, clients use a technology called a distributed hash table [PDF] (DHT).
When a person adds a torrent by using a magnet link, the DHT node contacts nearby nodes. Those nodes reach other nodes, and they keep talking to each other until one of them finds information about the torrent. In this way, each peer becomes a tracker. DHT can also work in tandem with traditional tracking technology. This provides a backup system in case the tracker fails.
Top 10 BitTorrent Clients
1. uTorrent (Beware of Malware filled ads/sponsored software)
Pronounced “micro torrent”, µTorrent is probably the most popular Windows client. The software is very lightweight (under 1 MB). Be wary of ads that contain malware when running it. Make sure not to allow it to install any annoying sponsored software during the initial setup. The app is available for all platforms. We do not recommend this client because it attempts to trick you into installing sponsored software.
Transmission is a favorite client for macOS, embedded systems, and Linux. It has a ton of features for power users, like speed limits, web seed support, magnet links, port forwarding and more. Transmission is an open-source client and doesn’t have ads or toolbars. It also doesn’t limit features to non-paying customers. The website claims that Transmission has the lowest memory usage of any BitTorrent client. Download it here.
3. BitTorrent (Beware of Malware filled ads/sponsored software)
Despite supporting µTorrent, BitTorrent, Inc. has an official client of their own. It is similar to µTorrent in that it has ads and software sponsors. Bittorrent has tons of features like scheduling torrents, automatically managing bandwidth and directories. It works with BitTorrent Remote. We do not recommend this client because it attempts to trick you into installing sponsored software.
qBittorrent is another open-source BitTorrent client. Features include an integrated search engine, remote control via a web interface, RSS support and much more. It is available on all platforms, and you can download it here.
Another open-source client, Deluge is available for all platforms. It is a lightweight program, with features like protocol encryption, DHT and a ton of plugins. It runs on desktops and as a client-server. I am currently using a Docker that runs Deluge and a built in VPN on FreeNAS 10 and could not be happier. Download it here.
Vuze claims to be the most powerful BitTorrent client on Earth. It has two products, a free client and a paid client called Vuze Plus. Vuze Plus offers DVD burning, built-in antivirus protection, playing downloads still in progress and automated subscriptions. However, the service is $29.90 for one year. Download it here.
BitComet is a C++ client for Windows. Specifically it’s a BitTorrent/HTTP/FTP download client. It handles torrents as well as HTTP/FTP downloads so that you can hook it up right to an FTP server. Among other features, it offers “intelligent file renaming” which is excellent for users like me who organize files by type, name, etc. Download it here.
BitLord is a minimal torrent client that offers searching, streaming, torrent playlists, and reading/writing comments to make sure the torrent is legit. It is available for Mac and Windows. Download it here.
Tixati is another light client that says, “Contains NO Spyware and NO Ads!” Features include DHT, PEX, and Magnet link support, RC4 connection encryption for added security, UDP Peer Connections, and NAT router hole-punching, and advanced features such as RSS, IP Filtering, Event Scheduler. Download it for Windows and Linux here.
Tribler is a unique BitTorrent that uses the TOR onion routing protocol for enhanced privacy. When you download a file with Tribler, you are not getting pieces directly from a seeder. Three layers of proxies filter all downloads. They do however have a disclaimer that warns the anonymity feature is not yet mature. Read more and download it here.
There is plenty of software to use for torrenting, and they are easy to use. BitTorrent has plenty of other purposes besides pirating, and hopefully, we have shed some light on how it works.