What is BitTorrent
BitTorrent is a peer to peer (P2P) file sharing protocol. BitTorrent protocol was designed to easily share large files over internet. What happens here is that the initial or the first person who wants to share the file creates a .torrent file. This torrent file contains metadata about the original file. The torrent file creator then uploads the file to a tracker. Now if someone wants to download the original file they first download the torrent file. This .torrent file when opened with a BitTorrent client contains the information about the tracker and peices of the original file. Now the bitTorrent client contacts the tracker. The tracker then communicates with the client and provides them information about the peices of the file hosted on other peer’s computer(s). The client then starts downloading peices of the original file from different peers.
Those that have the full file on their computers and are connected to the tracker are called seeders. All clients connected to the tracker (seeders and lurkers or leechers) are called peers.
BitTorrent or Torrent Trackers
A tracker (also called torrent trackers or bittorrent trackers) is kind of a bridge between peers. BitTorrent trackers are servers which provide communication platform to peers. When you attempt to download a file using BitTorrent protocol, it is the trackers job to tell your bitTorrent client about other peers that have different peices of files. It is said that a tracker is a must to initiate a download but once the client has the peer list you can download without tracker information. However, sometimes peer go offline or some peices are missing in this case your clients communicates with the tracker again to gather information about new peers. A torrent tracker is not a torrent search index. Torrent indexers are servers that contain, collect and maintain information about torrents tracked by a tracker. This list is then available to peers to see what is available for download. In order to download the file they needed they communicate with the tracker and not with the indexer.
A BitTorrent Client is a program that assists in creating, sharing, uploading and downloading of a .torrent file and data. There are many BitTorrent clients available for download and a great number of them are freeware. I would like to mention a few very best of them:
I use µTorrent on Windows XP and Transmission on Ubuntu Linux.
Legal Issues and BitTorrent protocol
In most countries, it is illegal to download copyrighted material without permission from the copyright holder. Wikipedia has a great article about the legal issues and BitTorrent.
Torrent Search Engines
Downloading copyrighted material is illegal in most countries. Still there is a wealth of content available legally. For example many open source Linux distributions are shared using the BitTorrent protocol. Aspiring new artists share their content via BitTorrent protocol as they can not afford to distribute their content due to hosting and bandwidth issues. Among all the illegal content that is available on the internet there are lots of legal software and content that you are allowed to download. But how do you know what is available for download? For that purpose there are many torrent search engines. These search engines maintain their own index of torrent files that are tracked by trackers. Sometimes the tracker and indexer would be provided by the same group or sometimes you will be redirected to the tracker.
- Linux Tracker My personal favorite, it has helped download many Linux distributions.
Word of Caution
You would think that downloading illegal or pirated software via torrents would save you money and time. But this is certainly not the case. Popular software downloaded from these sources sometimes contain harmful viruses and trojans that could destroy your data. So please don’t download illegal/pirated software for your own safety. If you really want something desperately look around for open source solutions you will definitely find some open source or free software available to do the job.