Network News Transfer Protocol (NNTP)

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Definition of NNTP in Network Encyclopedia.

What is Network News Transfer Protocol ( NNTP )?

NNTP stands for Network News Transfer Protocol is an Internet standard protocol that governs the interaction between Network News Transfer Protocol (NNTP) servers (news servers) and NNTP clients (news readers). NNTP is the underlying protocol on which the Usenet Internet news system is built.

NNTP – Network News Transfer Protocol

How It Works

NNTP is both a client/server protocol and a server/server protocol. It offers a set of simple text commands that

  • Enable NNTP clients such as Microsoft Outlook Express and Microsoft Internet Mail and News to use TCP port number 119 to connect to an NNTP service or daemon running on an NNTP server and download a list of newsgroups, read the messages in a newsgroup, or post a new message to a newsgroup.
  • Enable NNTP servers such as Internet Information Server (IIS) 4 running the NNTP Service or Microsoft Exchange Server 5.5 running the Microsoft Exchange Internet News Service to connect to other NNTP servers on the Internet and replicate newsgroups and their content among each other. This replication process between NNTP servers (or hosts, as they are called) forms the basis of the worldwide news system called Usenet.

NNTP connections between clients and servers and between servers and servers use Transmission Control Protocol (TCP) for reliable, guaranteed packet delivery. Clients connecting to servers might require authentication before their NNTP commands are accepted.

NNTP client commands include the following:

  • LIST: To obtain a list of newsgroups available on the server 
  • GROUP: To select a specific newsgroup 
  • ARTICLE: To display a selected message 
  • POST: To post a new message or reply to an existing one 
  • HELP: Provides a short summary of commands that are understood by this implementation of the server
  • IHAVE: Informs the server that the client has an article
  • NEWGROUPS: List of newsgroups created since…

NNTP Responses

Response codes for Network News Transfer Protocol:

   200 server ready - posting allowed
   201 server ready - no posting allowed
   202 slave status noted
   205 closing connection - goodbye!
   211 n f l s group selected
   215 list of newsgroups follows
   220 n <a> article retrieved - head and body follow 221 n <a> article
   retrieved - head follows
   222 n <a> article retrieved - body follows
   223 n <a> article retrieved - request text separately 230 list of new
   articles by message-id follows
   231 list of new newsgroups follows
   235 article transferred ok
   240 article posted ok

   335 send article to be transferred.  End with <CR-LF>.<CR-LF>
   340 send article to be posted. End with <CR-LF>.<CR-LF>

   400 service discontinued
   411 no such news group
   412 no newsgroup has been selected
   420 no current article has been selected
   421 no next article in this group
   422 no previous article in this group
   423 no such article number in this group
   430 no such article found
   435 article not wanted - do not send it
   436 transfer failed - try again later
   437 article rejected - do not try again.
   440 posting not allowed
   441 posting failed

   500 command not recognized
   501 command syntax error
   502 access restriction or permission denied
   503 program fault - command not performed

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