Network News Transfer Protocol - NNTP

- NNTP specifies a protocol for the distribution, inquiry, retrieval, and posting of news articles using a reliable stream-based transmission of news among the ARPA-Internet community.
- NNTP is designed so that news articles are stored in a central database allowing a subscriber to select only those items he wishes to read. Indexing, cross-referencing, and expiration of aged messages are also provided.
- NNTP is designed so that news articles are stored in a central database allowing a subscriber to select only those items he wishes to read.
- The Network News Transfer Protocol (NNTP) established the technical foundation for the widely used Newsgroups.
- The NNTP protocol is the delivery mechanism for the USENET newsgroup service.
- NNTP is also used by clients who need to read news articles on USENET servers.
- NNTP uses an interactive command and response mechanism that lets hosts determine which articles are to be transmitted.
- Server-to-server exchanges : In the server-to-server exchange, one server either requests the latest articles from another server (pull) or allows the other server to push new articles to it.
- User-to-server connections : The user first connects with a newsgroup server (usually located at an ISP (Internet service provider), then downloads a list of available newsgroups. The user can then subscribe to a newsgroup and begin reading articles available in that group or post new articles.

Protocol Structure - NNTP

NNTP uses commands and responces for communications.
- Article - Display the header, a blank line, then the body (text) of the specified article.
- Head : Identical to the ARTICLE command except that they respectively return only the header lines or text body of the article.
- Status : Similar to the ARTICLE command except that no text is returned.
- Group : The required parameter ggg is the name of the newsgroup to be selected.
- Body : Identical to the ARTICLE command except that they respectively return only the header lines or text body of the article.
- List : Returns a list of valid newsgroups and associated information.
- NewsGroups : A list of newsgroups created since will be listed in the same format as the LIST command.
- ewNews : A list of message-ids of articles posted or received to the specified newsgroup since "date" will be listed.
- Next : The internally maintained "current article pointer" is advanced to the next article in the current newsgroup.
- Post : If posting is allowed, response code 340 is returned to indicate that the article to be posted should be sent.
- Quit : The server process acknowledges the QUIT command and then closes the connection to the client.