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.
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
External References:
- NNTP is defined in Request for Comments (RFC) 977.
