The Napster network was created at application-level using a client-server protocol over point-to-point TCP. The server was in this case a centralized directory that would hold an index of all files offered (MP3/WMA). The clients would connect to the server, identify themselves to the server (users had an account on the server) and send a list of MP3/WMA files they were sharing to it enabling other clients to search that central repository for any file on the network and then request it from any available source.
- OpenNap ( http://opennap.sourceforge.net ), a Napster based peer-to-peer, created as open source (GPL), in C using Win32, and so for Windows. Intended to extend the Napster protocol to allow sharing of any media type, and adding the ability to link servers together. Discontinued.
- audioGnome ( http://www.audiognome.com ), closed source but as freeware for Windows.
- JNerve ( http://jnerve.sourceforge.net ), an open source (GPL) Java Napster Server Protocol implementation with a goal of cross-platform compatibility.
- Napsack ( http://napsack.sourceforge.net ) is a specialized multi-threaded client for broadcasting Napster queries across multiple servers; the list of target servers is retrieved from www.napigator.com, and is user-filterable (based on the number of users, files, or gigs indexed). Opensourced (GPL) using Java.