Network News Transfer Protocol
NNTP (Network News Transfer Protocol) is a protocol for transmission of messages in newsgroups. It is used on Usenet. Its specifications were defined in RFC 977 ( February 1986). Some extensions of the standard protocol were held in RFC 2980 (October 2000). In October 2006 RFC 3977 was published, which replaces the previous two or expanded. The message format is defined in RFC 5536 ( November 2009). The IANA has assigned the protocol to TCP port 119.
NNTP is text-based and looks alternately requests from the client and on the server before the following answers. These responses include a first line with a numeric status code - a three-digit integer that indicates the success of the command - and further information, depending on the request. In some cases also follow additional lines, always terminated by a line containing a single dot.
The URL of an NNTP discussion forum or news site has the following structure:
Nntp :/ /
The original specification already defines a sufficient number of 1986 commands to allow communication between the server and client. This section introduces the most important commands.
- HELP: lists the supported commands.
- LIST: returns the names of the newsgroups available to the user, one per line.
- GROUP: lets the user select a new current group.
- ARTICLE: requests an item, either by its number in the group currently selected, or using its message ID.
- POST: allows the server to pass a new article.