NNTP (Network News Transfer Protocol) is a protocol used by Usenet servers and clients to distribute, share, retrieve and post news articles. This protocol interacts between news servers and news reader programs. Any posted to a news group it must be sent through this protocol. NNTP operated at Application layer of the OSI model.

Actually Usenet is a world-wide distributed shared message system. It consists of set of newsgroup like comp, hardware, sport etc. INN and Diablo are some popular NNTP servers. NNTP clients vary according to operating system. In Microsoft Windows Xnews and Dialog are available NNTP clients where as in UNIX rn, trn and nn are available. Pan is one NNTP newsreader which is available for almost all of the today’s operating systems.