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The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  TCP/IP Key Applications and Application Protocols            9  TCP/IP File and Message Transfer Applications and Protocols (FTP, TFTP, Electronic Mail, USENET, HTTP/WWW, Gopher)                 9  Usenet (Network News) and the TCP/IP Network News Transfer Protocol (NNTP)                      9  TCP/IP Network News Transfer Protocol (NNTP)

NNTP Client-Server Communication Process: News Posting and Access 1 2 NNTP Command Extensions

One of the great strengths of the open, cooperative process used to develop Internet standards, is that new protocols are usually designed by building upon successes in older ones. This both saves development time and effort, and promotes compatibility between technologies. As I explained in the overview of NNTP, it was based in many ways on principles from SMTP; SMTP in turn borrowed ideas from earlier protocols, Telnet and FTP. This legacy can be seen in the similarities between NNTP commands and those of these earlier protocols.

As in SMTP, all NNTP commands are ASCII text that are sent over the NNTP TCP connection to an NNTP server, from the device acting as the client (which may be a newsreader client or an NNTP server itself). These are standard text strings adhering to the Telnet Network Virtual Terminal (NVT) format, terminated by the two-character “CRLF” sequence. As is the case with SMTP and FTP, you can conduct an interactive session with an NNTP server by using Telnet to connect to it on port 119.

The basic syntax of an NNTP command is as follows:

<command-code> <parameters>

Unlike SMTP, NNTP commands are not restricted to a length of four characters. The parameters that follow the command are separated by one or more space characters, and are used to provide necessary information to allow the server to execute the command. NNTP commands are not case-sensitive.

NNTP Client-Server Communication Process: News Posting and Access 1 2 NNTP Command Extensions