How BitTorrent Works

To use BitTorrent for file downloads, you need to install the BitTorrent client software. You may also need to tweak your firewall and network router (if you use these) to accept BitTorrent files. We'll give you all the details to get started. But first, here's a synopsis of the steps:

Download the BitTorrent Client Software

BitTorrent is open-source software, which means the program is available to you and to software developers for free (see What does "open source" mean?). Therefore, some developers have created their own versions of BitTorrent software, and you can choose from a number of client programs. (Note: This article assumes you are using the official version. If you want to experiment with different clients, see Brian's BitTorrent FAQ and Guide for a list.)

To start off, go to BitTorrent.com and click the link for the client software that matches your operating system. After you download the client software, double-click on the desktop icon to install it. The installation program is quick, and it displays this window when it is complete:

You'll also see Bram Cohen's Web page, where you can send donations to support development of BitTorrent. Mr. Cohen develops and distributes BitTorrent as open-source software at no cost to users or other developers.

Check and Configure Firewall

If you have a firewall installed on your computer, you will obtain faster download rates if you configure it to have an open pathway for BitTorrent file transfers. A firewall protects your system from intruders by disallowing unauthorized access to your computer's ports. A port is a way for Internet communications to travel into and out of your computer. Ports are numbered, and each communication type has a standard port number. See How Web Servers Work to learn more.

BitTorrent also uses specific port numbers, normally ports 6881 through 6889. Because firewalls block these ports by default, you'll need to configure your firewall to accept this incoming traffic in order to receive .torrent files. You may also have to enable port forwarding of your computer's IP address for ports 6881 through 6889 so that other BitTorrent computers can find you. Because every product is unique, check the documentation or product Web site for your firewall/router for specific instructions on how to accomplish these tasks. You can also check out PortForward.com for help.

Once you have everything set up, you'll probably want to find some files to download. Next, we'll discuss where to look and the legal ramifications of downloading what you find.