Gnutella

A popular peer-to-peer file sharing network on the Internet. Gnutella lets users share files from user machine to user machine without the use of a central directory, which was the original Napster architecture. Numerous client programs, such as LimeWire, Morpheus, BearShare and Mutella, have been developed that incorporate the Gnutella file sharing protocol. For more information, visit www.gnutella.com.

Developed by Nullsoft/AOL
Nullsoft, makers of the popular Winamp software media player, was acquired by AOL in 1999. In 2000, the Nullsoft division released the Gnutella software on the Internet, but AOL quickly pulled the plug the next day. However, licensed under the GNU General Public License (GPL), Gnutella spread rapidly in that short time, and Gnutella clients emerged soon after. The Gnutella name is a combination of GNU from the license and the chocolate-hazelnut spread Nutella.

How Files Are Shared
Each client in a Gnutella network is also a server, and the term "servent" is the combination of server and client. When starting for the first time, each Gnutella servent requires the IP address of at least one other servent, which it can obtain from a default list of UDP host caches (UHCs) or GWebcaches. UHCs crawl the Internet looking for Gnutella hosts (servents), and GWebcache servers are updated by the Gnutella hosts themselves.

Once a servent contacts another servent, that servent tries to contact the nodes it is aware of, and the request gets forwarded throughout the Gnutella network until the request times out. High-speed, non-firewalled servents can become "ultrapeers," which can connect to 32 other ultrapeers and 30 regular servents. The ultrapeers maintain key words of the files in the servents and forward them only requests for files they are likely to have. See peer-to-peer network.