Network News Transfer Protocol (NNTP)
So far, we have looked at three of the protocols used in sending and retrieving Internet Mail. However, mail is not the only method used for the dissemination of information across the Internet. Instances often arise where a particular message is of interest to a wide number of users. As the appeal of the message grows, so the inefficiencies of using a mail-based mechanism for transporting that message increase also, as the practice of sending a separate copy of the message to each of the interested parties consumes large quantities of bandwidth, CPU resources and disk space among the many destinations.
Significant economies can be achieved if these popular messages are hosted in a single database instead of in each subscriber's mailbox. This single database is a news server and the messages on such a server are called news items or articles. NNTP (the Network News Transfer Protocol) defines a protocol for the distribution, inquiry, posting and retrieval of such news items between a news server and clients and is designed to allow messages to be stored on a central host server with clients connecting via a connection stream such as TCP. (News distribution between servers typically uses another protocol called Unix-to-Unix Copy or UUCP).
The NNTP protocol also allows for the introduction of intermediate or 'slave' servers that accept newsfeeds from central master news servers and in turn provide service of these cached news articles to local clients.