Gnutella is a decentralized peer-to-peer file sharing network. With similar results as the old Napster, users of Gnutella are able to search for a song or file through one of Gnutella’s clients and then download that file onto his or her own hard drive. What makes Gnutella different from Napster is the fact that it lacks a central server and, instead, each of the computers networked perform as both server and client.
To use Gnutella, users place files they are willing to share on hard disks and make them available to others for downloading in the normal peer-to-peer method. Then, using one of Gnutella’s numerous clients including BearShare, Gnucleus, LimeWire, Morpehus, WinMX and XoloX, a user types in the name of the song or file into the software’s search field. The computer then connects to at least one other computer through Gnutella and looks to see if that computer has the desired file. The computer has either been programmed with another computer’s IP address or uses one of its software’s pre-programmed servers. That computer then connects to at least one other and the process continues on and on and on, until either the file is found or the search’s time to live (TTL) limit has run out.
One of Gnutella's most touted qualities is the fact that it is always working; if a user is able to connect with at least one other computer, the entire network is queried during the search, not merely one server. This does, however, mean that there is no guarantee the desired file is on any of the computers reached through the network. The search can also take a minute or more before a response is received.
Although Gnutella is itself legal in the United States, since sharing public domain files is legal, the act of using Gnutella to distribute copyrighted music and other files is illegal. However, Gnutella’s lack of one central server makes it very difficult for a court order to shut down the service. Some opponents of the service have found ways to upset the network with an overload of fake searches or flood of corrupt files.
Gnutella’s first client was developed in 2000 by Nullsoft, which had just been acquired by AOL. The program was made available for download on the company’s servers for one day — March 14, 2000. AOL later pulled down the program due to legal concerns, but not before thousands had downloaded the program. These downloaded copies spurred open-source and free clones, which continues to be the way Gnutella exists today.