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How To Prevent Peer-to-Peer Network Abuse: Page 2 of 6

Making the Connection

Since some peer-to-peer systems don't have easily defined servers, how do the networks form in the first place? Most applications have a small list of predefined well-known peers, along with their installers. When the applications run for the first time, they attempt to connect to this list of peers and download a new list. By continually updating these lists, the peers should always have a working connection. Gnutella clients also can fetch these lists from Web sites, so if they are completely unable to connect at first, they can try a fresh list of possible connections. Some Web sites also house updated lists for other protocols that users can download manually, if all else fails.

Once a list has been generated, the clients attempt to connect to the network. Several protocols, including Gnutella, BitTorrent and eDonkey, use a well-known range of ports by default. Unfortunately, FastTrack does not. FastTrack uses three different connection methods to work its way around firewalls, each progressively harder to detect.

FastTrack Connections

FastTrack's supernodes are essentially normal clients that have spare resources. "Spare" bandwidth, processor power and memory are examined, and if there are enough available resources, a node is promoted to a supernode. Once a client becomes a supernode, it uses more bandwidth by accepting other client connections and relaying queries for them. When clients connect, the supernode indexes any files they are providing, essentially caching the information for slower nodes in the network.