Stands for "Network News Transfer Protocol." NNTP is the protocol used to connect to Usenet servers and transfer newsgroup articles between systems over the Internet. It is similar to the SMTP protocol used for sending email messages, but is designed specifically for newsgroup articles.
NNTP enables both server/server and client/server communication. NNTP servers, for example, can communicate with each other and replicate newsgroups among each other. This is how the Usenet network is created and maintained. In the client-server model, NNTP allows a client system to connect to a Usenet server and provides commands for browsing and viewing articles on the server.
Usenet was originally based on UUCP (Unix-to-Unix Copy), an early protocol used for file transfers between Unix systems. The only way to read articles via UUCP was to log into a Usenet server and read articles directly from the local disk. NNTP made it possible to access a Usenet server remotely from a client system running newsreader software.
Examples of commands supported by the Network News Transfer Protocol include:
- ARTICLE - retrieve an article from a Usenet server
- GROUP - select a specific newsgroup
- IHAVE - tell the server the client has an article it may want
- LIST - retrieve a list of newsgroups available on the server
- NEWSGROUPS - receive a list of newsgroups created after a specific date and time
- NEWNEWS - receive a list of articles created after a specific date and time
- NEXT - Go to the next message in the newsgroup
- POST - post a message or reply to an existing one
In most cases, these and other NNTP commands are handled automatically by newsreader software. Newsreaders use these commands to communicate with Usenet servers and provide a graphical user interface GUI for browsing and viewing articles on the server.