Network Working Group                      Brian Kantor (U.C. San Diego)
Request for Comments: 977                   Phil Lapsley (U.C. Berkeley)
                                                          February 1986

                    Network News Transfer Protocol

               A Proposed Standard for the Stream-Based
                         Transmission of News

Status of This Memo

  NNTP specifies a protocol for the distribution, inquiry, retrieval,
  and posting of news articles using a reliable stream-based
  transmission of news among the ARPA-Internet community.  NNTP is
  designed so that news articles are stored in a central database
  allowing a subscriber to select only those items he wishes to read.
  Indexing, cross-referencing, and expiration of aged messages are also
  provided. This RFC suggests a proposed protocol for the ARPA-Internet
  community, and requests discussion and suggestions for improvements.
  Distribution of this memo is unlimited.

1.  Introduction

  For many years, the ARPA-Internet community has supported the
  distribution of bulletins, information, and data in a timely fashion
  to thousands of participants.  We collectively refer to such items of
  information as "news".  Such news provides for the rapid
  dissemination of items of interest such as software bug fixes, new
  product reviews, technical tips, and programming pointers, as well as
  rapid-fire discussions of matters of concern to the working computer
  professional. News is very popular among its readers.

  There are popularly two methods of distributing such news: the
  Internet method of direct mailing, and the USENET news system.

1.1.  Internet Mailing Lists

  The Internet community distributes news by the use of mailing lists.
  These are lists of subscriber's mailbox addresses and remailing
  sublists of all intended recipients.  These mailing lists operate by
  remailing a copy of the information to be distributed to each
  subscriber on the mailing list.  Such remailing is inefficient when a
  mailing list grows beyond a dozen or so people, since sending a
  separate copy to each of the subscribers occupies large quantities of
  network bandwidth, CPU resources, and significant amounts of disk
  storage at the destination host.  There is also a significant problem
  in maintenance of the list itself: as subscribers move from one job
  to another; as new subscribers join and old ones leave; and as hosts
  come in and out of service.




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RFC 977                                                    February 1986
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1.2.  The USENET News System

  Clearly, a worthwhile reduction of the amount of these resources used
  can be achieved if articles are stored in a central database on the
  receiving host instead of in each subscriber's mailbox. The USENET
  news system provides a method of doing just this.  There is a central
  repository of the news articles in one place (customarily a spool
  directory of some sort), and a set of programs that allow a
  subscriber to select those items he wishes to read.  Indexing,
  cross-referencing, and expiration of aged messages are also provided.

1.3.  Central Storage of News

  For clusters of hosts connected together by fast local area networks
  (such as Ethernet), it makes even more sense to consolidate news
  distribution onto one (or a very few) hosts, and to allow access to
  these news articles using a server and client model.  Subscribers may
  then request only the articles they wish to see, without having to
  wastefully duplicate the storage of a copy of each item on each host.

1.4.  A Central News Server

  A way to achieve these economies is to have a central computer system
  that can provide news service to the other systems on the local area
  network.  Such a server would manage the collection of news articles
  and index files, with each person who desires to read news bulletins
  doing so over the LAN.  For a large cluster of computer systems, the
  savings in total disk space is clearly worthwhile.  Also, this allows
  workstations with limited disk storage space to participate in the
  news without incoming items consuming oppressive amounts of the
  workstation's disk storage.

  We have heard rumors of somewhat successful attempts to provide
  centralized news service using IBIS and other shared or distributed
  file systems.  While it is possible that such a distributed file
  system implementation might work well with a group of similar
  computers running nearly identical operating systems, such a scheme
  is not general enough to offer service to a wide range of client
  systems, especially when many diverse operating systems may be in use
  among a group of clients.  There are few (if any) shared or networked
  file systems that can offer the generality of service that stream
  connections using Internet TCP provide, particularly when a wide
  range of host hardware and operating systems are considered.

  NNTP specifies a protocol for the distribution, inquiry, retrieval,
  and posting of news articles using a reliable stream (such as TCP)
  server-client model. NNTP is designed so that news articles need only


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  be stored on one (presumably central) host, and subscribers on other
  hosts attached to the LAN may read news articles using stream
  connections to the news host.

  NNTP is modelled upon the news article specifications in RFC 850,
  which describes the USENET news system.  However, NNTP makes few
  demands upon the structure, content, or storage of news articles, and
  thus we believe it easily can be adapted to other non-USENET news
  systems.

  Typically, the NNTP server runs as a background process on one host,
  and would accept connections from other hosts on the LAN.  This works
  well when there are a number of small computer systems (such as
  workstations, with only one or at most a few users each), and a large
  central server.

1.5.  Intermediate News Servers

  For clusters of machines with many users (as might be the case in a
  university or large industrial environment), an intermediate server
  might be used.  This intermediate or "slave" server runs on each
  computer system, and is responsible for mediating news reading
  requests and performing local caching of recently-retrieved news
  articles.

  Typically, a client attempting to obtain news service would first
  attempt to connect to the news service port on the local machine.  If
  this attempt were unsuccessful, indicating a failed server, an
  installation might choose to either deny news access, or to permit
  connection to the central "master" news server.

  For workstations or other small systems, direct connection to the
  master server would probably be the normal manner of operation.

  This specification does not cover the operation of slave NNTP
  servers.  We merely suggest that slave servers are a logical addition
  to NNTP server usage which would enhance operation on large local
  area networks.

1.6.  News Distribution

  NNTP has commands which provide a straightforward method of
  exchanging articles between cooperating hosts. Hosts which are well
  connected on a local area or other fast network and who wish to
  actually obtain copies of news articles for local storage might well
  find NNTP to be a more efficient way to distribute news than more
  traditional transfer methods (such as UUCP).


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  In the traditional method of distributing news articles, news is
  propagated from host to host by flooding - that is, each host will
  send all its new news articles on to each host that it feeds.  These
  hosts will then in turn send these new articles on to other hosts
  that they feed.  Clearly, sending articles that a host already has
  obtained a copy of from another feed (many hosts that receive news
  are redundantly fed) again is a waste of time and communications
  resources, but for transport mechanisms that are single-transaction
  based rather than interactive (such as UUCP in the UNIX-world <1>),
  distribution time is diminished by sending all articles and having
  the receiving host simply discard the duplicates.  This is an
  especially true when communications sessions are limited to once a
  day.

  Using NNTP, hosts exchanging news articles have an interactive
  mechanism for deciding which articles are to be transmitted.  A host
  desiring new news, or which has new news to send, will typically
  contact one or more of its neighbors using NNTP.  First it will
  inquire if any new news groups have been created on the serving host
  by means of the NEWGROUPS command.  If so, and those are appropriate
  or desired (as established by local site-dependent rules), those new
  newsgroups can be created.

  The client host will then inquire as to which new articles have
  arrived in all or some of the newsgroups that it desires to receive,
  using the NEWNEWS command.  It will receive a list of new articles
  from the server, and can request transmission of those articles that
  it desires and does not already have.

  Finally, the client can advise the server of those new articles which
  the client has recently received.  The server will indicate those
  articles that it has already obtained copies of, and which articles
  should be sent to add to its collection.

  In this manner, only those articles which are not duplicates and
  which are desired are transferred.













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RFC 977                                                    February 1986
Network News Transfer Protocol


2.  The NNTP Specification

2.1.  Overview

  The news server specified by this document uses a stream connection
  (such as TCP) and SMTP-like commands and responses.  It is designed
  to accept connections from hosts, and to provide a simple interface
  to the news database.

  This server is only an interface between programs and the news
  databases. It does not perform any user interaction or presentation-
  level functions. These "user-friendly" functions are better left to
  the client programs, which have a better understanding of the
  environment in which they are operating.

  When used via Internet TCP, the contact port assigned for this
  service is 119.

2.2.  Character Codes

  Commands and replies are composed of characters from the ASCII
  character set.  When the transport service provides an 8-bit byte
  (octet) transmission channel, each 7-bit character is transmitted
  right justified in an octet with the high order bit cleared to zero.

2.3.  Commands

  Commands consist of a command word, which in some cases may be
  followed by a parameter.  Commands with parameters must separate the
  parameters from each other and from the command by one or more space
  or tab characters.  Command lines must be complete with all required
  parameters, and may not contain more than one command.

  Commands and command parameters are not case sensitive. That is, a
  command or parameter word may be upper case, lower case, or any
  mixture of upper and lower case.

  Each command line must be terminated by a CR-LF (Carriage Return -
  Line Feed) pair.

  Command lines shall not exceed 512 characters in length, counting all
  characters including spaces, separators, punctuation, and the
  trailing CR-LF (thus there are 510 characters maximum allowed for the
  command and its parameters).  There is no provision for continuation
  command lines.




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2.4.  Responses

  Responses are of two kinds, textual and status.

2.4.1.  Text Responses

  Text is sent only after a numeric status response line has been sent
  that indicates that text will follow.  Text is sent as a series of
  successive lines of textual matter, each terminated with CR-LF pair.
  A single line containing only a period (.) is sent to indicate the
  end of the text (i.e., the server will send a CR-LF pair at the end
  of the last line of text, a period, and another CR-LF pair).

  If the text contained a period as the first character of the text
  line in the original, that first period is doubled.  Therefore, the
  client must examine the first character of each line received, and
  for those beginning with a period, determine either that this is the
  end of the text or whether to collapse the doubled period to a single
  one.

  The intention is that text messages will usually be displayed on the
  user's terminal whereas command/status responses will be interpreted
  by the client program before any possible display is done.

2.4.2.  Status Responses

  These are status reports from the server and indicate the response to
  the last command received from the client.

  Status response lines begin with a 3 digit numeric code which is
  sufficient to distinguish all responses.  Some of these may herald
  the subsequent transmission of text.

  The first digit of the response broadly indicates the success,
  failure, or progress of the previous command.

     1xx - Informative message
     2xx - Command ok
     3xx - Command ok so far, send the rest of it.
     4xx - Command was correct, but couldn't be performed for
           some reason.
     5xx - Command unimplemented, or incorrect, or a serious
           program error occurred.






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  The next digit in the code indicates the function response category.

     x0x - Connection, setup, and miscellaneous messages
     x1x - Newsgroup selection
     x2x - Article selection
     x3x - Distribution functions
     x4x - Posting
     x8x - Nonstandard (private implementation) extensions
     x9x - Debugging output

  The exact response codes that should be expected from each command
  are detailed in the description of that command.  In addition, below
  is listed a general set of response codes that may be received at any
  time.

  Certain status responses contain parameters such as numbers and
  names. The number and type of such parameters is fixed for each
  response code to simplify interpretation of the response.

  Parameters are separated from the numeric response code and from each
  other by a single space. All numeric parameters are decimal, and may
  have leading zeros. All string parameters begin after the separating
  space, and end before the following separating space or the CR-LF
  pair at the end of the line. (String parameters may not, therefore,
  contain spaces.) All text, if any, in the response which is not a
  parameter of the response must follow and be separated from the last
  parameter by a space.  Also, note that the text following a response
  number may vary in different implementations of the server. The
  3-digit numeric code should be used to determine what response was
  sent.

  Response codes not specified in this standard may be used for any
  installation-specific additional commands also not specified. These
  should be chosen to fit the pattern of x8x specified above.  (Note
  that debugging is provided for explicitly in the x9x response codes.)
  The use of unspecified response codes for standard commands is
  prohibited.

  We have provided a response pattern x9x for debugging.  Since much
  debugging output may be classed as "informative messages", we would
  expect, therefore, that responses 190 through 199 would be used for
  various debugging outputs.  There is no requirement in this
  specification for debugging output, but if such is provided over the
  connected stream, it must use these response codes.  If appropriate
  to a specific implementation, other x9x codes may be used for
  debugging.  (An example might be to use e.g., 290 to acknowledge a
  remote debugging request.)


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2.4.3.  General Responses

  The following is a list of general response codes that may be sent by
  the NNTP server.  These are not specific to any one command, but may
  be returned as the result of a connection, a failure, or some unusual
  condition.

  In general, 1xx codes may be ignored or displayed as desired;  code
  200 or 201 is sent upon initial connection to the NNTP server
  depending upon posting permission; code 400 will be sent when the
  NNTP server discontinues service (by operator request, for example);
  and 5xx codes indicate that the command could not be performed for
  some unusual reason.

     100 help text
     190
       through
     199 debug output

     200 server ready - posting allowed
     201 server ready - no posting allowed

     400 service discontinued

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

3.  Command and Response Details

  On the following pages are descriptions of each command recognized by
  the NNTP server and the responses which will be returned by those
  commands.

  Each command is shown in upper case for clarity, although case is
  ignored in the interpretation of commands by the NNTP server.  Any
  parameters are shown in lower case.  A parameter shown in [square
  brackets] is optional.  For example, [GMT] indicates that the
  triglyph GMT may present or omitted.

  Every command described in this section must be implemented by all
  NNTP servers.






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  There is no prohibition against additional commands being added;
  however, it is recommended that any such unspecified command begin
  with the letter "X" to avoid conflict with later revisions of this
  specification.

  Implementors are reminded that such additional commands may not
  redefine specified status response codes.  Using additional
  unspecified responses for standard commands is also prohibited.

3.1.  The ARTICLE, BODY, HEAD, and STAT commands

  There are two forms to the ARTICLE command (and the related BODY,
  HEAD, and STAT commands), each using a different method of specifying
  which article is to be retrieved.  When the ARTICLE command is
  followed by a message-id in angle brackets ("<" and ">"), the first
  form of the command is used; when a numeric parameter or no parameter
  is supplied, the second form is invoked.

  The text of the article is returned as a textual response, as
  described earlier in this document.

  The HEAD and BODY commands are identical to the ARTICLE command
  except that they respectively return only the header lines or text
  body of the article.

  The STAT command is similar to the ARTICLE command except that no
  text is returned.  When selecting by message number within a group,
  the STAT command serves to set the current article pointer without
  sending text. The returned acknowledgement response will contain the
  message-id, which may be of some value.  Using the STAT command to
  select by message-id is valid but of questionable value, since a
  selection by message-id does NOT alter the "current article pointer".

3.1.1.  ARTICLE (selection by message-id)

  ARTICLE <message-id>

  Display the header, a blank line, then the body (text) of the
  specified article.  Message-id is the message id of an article as
  shown in that article's header.  It is anticipated that the client
  will obtain the message-id from a list provided by the NEWNEWS
  command, from references contained within another article, or from
  the message-id provided in the response to some other commands.

  Please note that the internally-maintained "current article pointer"
  is NOT ALTERED by this command. This is both to facilitate the
  presentation of articles that may be referenced within an article


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  being read, and because of the semantic difficulties of determining
  the proper sequence and membership of an article which may have been
  posted to more than one newsgroup.

3.1.2.  ARTICLE (selection by number)

  ARTICLE [nnn]

  Displays the header, a blank line, then the body (text) of the
  current or specified article.  The optional parameter nnn is the

  numeric id of an article in the current newsgroup and must be chosen
  from the range of articles provided when the newsgroup was selected.
  If it is omitted, the current article is assumed.

  The internally-maintained "current article pointer" is set by this
  command if a valid article number is specified.

  [the following applies to both forms of the article command.] A
  response indicating the current article number, a message-id string,
  and that text is to follow will be returned.

  The message-id string returned is an identification string contained
  within angle brackets ("<" and ">"), which is derived from the header
  of the article itself.  The Message-ID header line (required by
  RFC850) from the article must be used to supply this information. If
  the message-id header line is missing from the article, a single
  digit "0" (zero) should be supplied within the angle brackets.

  Since the message-id field is unique with each article, it may be
  used by a news reading program to skip duplicate displays of articles
  that have been posted more than once, or to more than one newsgroup.

3.1.3.  Responses

  220 n <a> article retrieved - head and body follow
          (n = article number, <a> = message-id)
  221 n <a> article retrieved - head follows
  222 n <a> article retrieved - body follows
  223 n <a> article retrieved - request text separately
  412 no newsgroup has been selected
  420 no current article has been selected
  423 no such article number in this group
  430 no such article found





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3.2.  The GROUP command

3.2.1.  GROUP

  GROUP ggg

  The required parameter ggg is the name of the newsgroup to be
  selected (e.g. "net.news").  A list of valid newsgroups may be
  obtained from the LIST command.

  The successful selection response will return the article numbers of
  the first and last articles in the group, and an estimate of the
  number of articles on file in the group.  It is not necessary that
  the estimate be correct, although that is helpful; it must only be
  equal to or larger than the actual number of articles on file.  (Some
  implementations will actually count the number of articles on file.
  Others will just subtract first article number from last to get an
  estimate.)

  When a valid group is selected by means of this command, the
  internally maintained "current article pointer" is set to the first
  article in the group.  If an invalid group is specified, the
  previously selected group and article remain selected.  If an empty
  newsgroup is selected, the "current article pointer" is in an
  indeterminate state and should not be used.

  Note that the name of the newsgroup is not case-dependent.  It must
  otherwise match a newsgroup obtained from the LIST command or an
  error will result.

3.2.2.  Responses

  211 n f l s group selected
          (n = estimated number of articles in group,
          f = first article number in the group,
          l = last article number in the group,
          s = name of the group.)
  411 no such news group











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RFC 977                                                    February 1986
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3.3.  The HELP command

3.3.1.  HELP

  HELP

  Provides a short summary of commands that are understood by this
  implementation of the server. The help text will be presented as a
  textual response, terminated by a single period on a line by itself.

  3.3.2.  Responses

  100 help text follows

3.4.  The IHAVE command

3.4.1.  IHAVE

  IHAVE <messageid>

  The IHAVE command informs the server that the client has an article
  whose id is <messageid>.  If the server desires a copy of that
  article, it will return a response instructing the client to send the
  entire article.  If the server does not want the article (if, for
  example, the server already has a copy of it), a response indicating
  that the article is not wanted will be returned.

  If transmission of the article is requested, the client should send
  the entire article, including header and body, in the manner
  specified for text transmission from the server. A response code
  indicating success or failure of the transferral of the article will
  be returned.

  This function differs from the POST command in that it is intended
  for use in transferring already-posted articles between hosts.
  Normally it will not be used when the client is a personal
  newsreading program.  In particular, this function will invoke the
  server's news posting program with the appropriate settings (flags,
  options, etc) to indicate that the forthcoming article is being
  forwarded from another host.

  The server may, however, elect not to post or forward the article if
  after further examination of the article it deems it inappropriate to
  do so.  The 436 or 437 error codes may be returned as appropriate to
  the situation.

  Reasons for such subsequent rejection of an article may include such


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  problems as inappropriate newsgroups or distributions, disk space
  limitations, article lengths, garbled headers, and the like.  These
  are typically restrictions enforced by the server host's news
  software and not necessarily the NNTP server itself.

3.4.2.  Responses

  235 article transferred ok
  335 send article to be transferred.  End with <CR-LF>.<CR-LF>
  435 article not wanted - do not send it
  436 transfer failed - try again later
  437 article rejected - do not try again

  An implementation note:

  Because some host news posting software may not be able to decide
  immediately that an article is inappropriate for posting or
  forwarding, it is acceptable to acknowledge the successful transfer
  of the article and to later silently discard it.  Thus it is
  permitted to return the 235 acknowledgement code and later discard
  the received article.  This is not a fully satisfactory solution to
  the problem.  Perhaps some implementations will wish to send mail to
  the author of the article in certain of these cases.

3.5.  The LAST command

3.5.1.  LAST

  LAST

  The internally maintained "current article pointer" is set to the
  previous article in the current newsgroup.  If already positioned at
  the first article of the newsgroup, an error message is returned and
  the current article remains selected.

  The internally-maintained "current article pointer" is set by this
  command.

  A response indicating the current article number, and a message-id
  string will be returned.  No text is sent in response to this
  command.

3.5.2.  Responses

  223 n a article retrieved - request text separately
          (n = article number, a = unique article id)



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  412 no newsgroup selected
  420 no current article has been selected
  422 no previous article in this group

3.6.  The LIST command

3.6.1.  LIST

  LIST

  Returns a list of valid newsgroups and associated information.  Each
  newsgroup is sent as a line of text in the following format:

     group last first p

  where <group> is the name of the newsgroup, <last> is the number of
  the last known article currently in that newsgroup, <first> is the
  number of the first article currently in the newsgroup, and <p> is
  either 'y' or 'n' indicating whether posting to this newsgroup is
  allowed ('y') or prohibited ('n').

  The <first> and <last> fields will always be numeric.  They may have
  leading zeros.  If the <last> field evaluates to less than the
  <first> field, there are no articles currently on file in the
  newsgroup.

  Note that posting may still be prohibited to a client even though the
  LIST command indicates that posting is permitted to a particular
  newsgroup. See the POST command for an explanation of client
  prohibitions.  The posting flag exists for each newsgroup because
  some newsgroups are moderated or are digests, and therefore cannot be
  posted to; that is, articles posted to them must be mailed to a
  moderator who will post them for the submitter.  This is independent
  of the posting permission granted to a client by the NNTP server.

  Please note that an empty list (i.e., the text body returned by this
  command consists only of the terminating period) is a possible valid
  response, and indicates that there are currently no valid newsgroups.

3.6.2.  Responses

  215 list of newsgroups follows







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RFC 977                                                    February 1986
Network News Transfer Protocol


3.7.  The NEWGROUPS command

3.7.1.  NEWGROUPS

  NEWGROUPS date time [GMT] [<distributions>]

  A list of newsgroups created since <date and time> will be listed in
  the same format as the LIST command.

  The date is sent as 6 digits in the format YYMMDD, where YY is the
  last two digits of the year, MM is the two digits of the month (with
  leading zero, if appropriate), and DD is the day of the month (with
  leading zero, if appropriate).  The closest century is assumed as
  part of the year (i.e., 86 specifies 1986, 30 specifies 2030, 99 is
  1999, 00 is 2000).

  Time must also be specified.  It must be as 6 digits HHMMSS with HH
  being hours on the 24-hour clock, MM minutes 00-59, and SS seconds
  00-59.  The time is assumed to be in the server's timezone unless the
  token "GMT" appears, in which case both time and date are evaluated
  at the 0 meridian.

  The optional parameter "distributions" is a list of distribution
  groups, enclosed in angle brackets.  If specified, the distribution
  portion of a new newsgroup (e.g, 'net' in 'net.wombat') will be
  examined for a match with the distribution categories listed, and
  only those new newsgroups which match will be listed.  If more than
  one distribution group is to be listed, they must be separated by
  commas within the angle brackets.

  Please note that an empty list (i.e., the text body returned by this
  command consists only of the terminating period) is a possible valid
  response, and indicates that there are currently no new newsgroups.

3.7.2.  Responses

  231 list of new newsgroups follows












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RFC 977                                                    February 1986
Network News Transfer Protocol


3.8.  The NEWNEWS command

3.8.1.  NEWNEWS

  NEWNEWS newsgroups date time [GMT] [<distribution>]

  A list of message-ids of articles posted or received to the specified
  newsgroup since "date" will be listed. The format of the listing will
  be one message-id per line, as though text were being sent.  A single
  line consisting solely of one period followed by CR-LF will terminate
  the list.

  Date and time are in the same format as the NEWGROUPS command.

  A newsgroup name containing a "*" (an asterisk) may be specified to
  broaden the article search to some or all newsgroups.  The asterisk
  will be extended to match any part of a newsgroup name (e.g.,
  net.micro* will match net.micro.wombat, net.micro.apple, etc). Thus
  if only an asterisk is given as the newsgroup name, all newsgroups
  will be searched for new news.

  (Please note that the asterisk "*" expansion is a general
  replacement; in particular, the specification of e.g., net.*.unix
  should be correctly expanded to embrace names such as net.wombat.unix
  and net.whocares.unix.)

  Conversely, if no asterisk appears in a given newsgroup name, only
  the specified newsgroup will be searched for new articles. Newsgroup
  names must be chosen from those returned in the listing of available
  groups.  Multiple newsgroup names (including a "*") may be specified
  in this command, separated by a comma.  No comma shall appear after
  the last newsgroup in the list.  [Implementors are cautioned to keep
  the 512 character command length limit in mind.]

  The exclamation point ("!") may be used to negate a match. This can
  be used to selectively omit certain newsgroups from an otherwise
  larger list.  For example, a newsgroups specification of
  "net.*,mod.*,!mod.map.*" would specify that all net.<anything> and
  all mod.<anything> EXCEPT mod.map.<anything> newsgroup names would be
  matched.  If used, the exclamation point must appear as the first
  character of the given newsgroup name or pattern.

  The optional parameter "distributions" is a list of distribution
  groups, enclosed in angle brackets.  If specified, the distribution
  portion of an article's newsgroup (e.g, 'net' in 'net.wombat') will
  be examined for a match with the distribution categories listed, and
  only those articles which have at least one newsgroup belonging to


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RFC 977                                                    February 1986
Network News Transfer Protocol


  the list of distributions will be listed.  If more than one
  distribution group is to be supplied, they must be separated by
  commas within the angle brackets.

  The use of the IHAVE, NEWNEWS, and NEWGROUPS commands to distribute
  news is discussed in an earlier part of this document.

  Please note that an empty list (i.e., the text body returned by this
  command consists only of the terminating period) is a possible valid
  response, and indicates that there is currently no new news.

3.8.2.  Responses

  230 list of new articles by message-id follows

3.9.  The NEXT command

3.9.1.  NEXT

  NEXT

  The internally maintained "current article pointer" is advanced to
  the next article in the current newsgroup.  If no more articles
  remain in the current group, an error message is returned and the
  current article remains selected.

  The internally-maintained "current article pointer" is set by this
  command.

  A response indicating the current article number, and the message-id
  string will be returned.  No text is sent in response to this
  command.

3.9.2.  Responses

  223 n a article retrieved - request text separately
          (n = article number, a = unique article id)
  412 no newsgroup selected
  420 no current article has been selected
  421 no next article in this group









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RFC 977                                                    February 1986
Network News Transfer Protocol


3.10.  The POST command

3.10.1.  POST

  POST

  If posting is allowed, response code 340 is returned to indicate that
  the article to be posted should be sent. Response code 440 indicates
  that posting is prohibited for some installation-dependent reason.

  If posting is permitted, the article should be presented in the
  format specified by RFC850, and should include all required header
  lines. After the article's header and body have been completely sent
  by the client to the server, a further response code will be returned
  to indicate success or failure of the posting attempt.

  The text forming the header and body of the message to be posted
  should be sent by the client using the conventions for text received
  from the news server:  A single period (".") on a line indicates the
  end of the text, with lines starting with a period in the original
  text having that period doubled during transmission.

  No attempt shall be made by the server to filter characters, fold or
  limit lines, or otherwise process incoming text.  It is our intent
  that the server just pass the incoming message to be posted to the
  server installation's news posting software, which is separate from
  this specification.  See RFC850 for more details.

  Since most installations will want the client news program to allow
  the user to prepare his message using some sort of text editor, and
  transmit it to the server for posting only after it is composed, the
  client program should take note of the herald message that greeted it
  when the connection was first established. This message indicates
  whether postings from that client are permitted or not, and can be
  used to caution the user that his access is read-only if that is the
  case. This will prevent the user from wasting a good deal of time
  composing a message only to find posting of the message was denied.
  The method and determination of which clients and hosts may post is
  installation dependent and is not covered by this specification.

3.10.2.  Responses

  240 article posted ok
  340 send article to be posted. End with <CR-LF>.<CR-LF>
  440 posting not allowed
  441 posting failed



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RFC 977                                                    February 1986
Network News Transfer Protocol


  (for reference, one of the following codes will be sent upon initial
  connection; the client program should determine whether posting is
  generally permitted from these:) 200 server ready - posting allowed
  201 server ready - no posting allowed

3.11.  The QUIT command

3.11.1.  QUIT

  QUIT

  The server process acknowledges the QUIT command and then closes the
  connection to the client.  This is the preferred method for a client
  to indicate that it has finished all its transactions with the NNTP
  server.

  If a client simply disconnects (or the connection times out, or some
  other fault occurs), the server should gracefully cease its attempts
  to service the client.

3.11.2.  Responses

  205 closing connection - goodbye!

3.12.  The SLAVE command

3.12.1.  SLAVE

  SLAVE

  Indicates to the server that this client connection is to a slave
  server, rather than a user.

  This command is intended for use in separating connections to single
  users from those to subsidiary ("slave") servers.  It may be used to
  indicate that priority should therefore be given to requests from
  this client, as it is presumably serving more than one person.  It
  might also be used to determine which connections to close when
  system load levels are exceeded, perhaps giving preference to slave
  servers.  The actual use this command is put to is entirely
  implementation dependent, and may vary from one host to another.  In
  NNTP servers which do not give priority to slave servers, this
  command must nonetheless be recognized and acknowledged.

3.12.2.  Responses

  202 slave status noted


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RFC 977                                                    February 1986
Network News Transfer Protocol


4.  Sample Conversations

  These are samples of the conversations that might be expected with
  the news server in hypothetical sessions.  The notation C: indicates
  commands sent to the news server from the client program; S: indicate
  responses received from the server by the client.

4.1.  Example 1 - relative access with NEXT

  S:      (listens at TCP port 119)

  C:      (requests connection on TCP port 119)
  S:      200 wombatvax news server ready - posting ok

  (client asks for a current newsgroup list)
  C:      LIST
  S:      215 list of newsgroups follows
  S:      net.wombats 00543 00501 y
  S:      net.unix-wizards 10125 10011 y
          (more information here)
  S:      net.idiots 00100 00001 n
  S:      .

  (client selects a newsgroup)
  C:      GROUP net.unix-wizards
  S:      211 104 10011 10125 net.unix-wizards group selected
          (there are 104 articles on file, from 10011 to 10125)

  (client selects an article to read)
  C:      STAT 10110
  S:      223 10110 <[email protected]> article retrieved - statistics
          only (article 10110 selected, its message-id is
          <[email protected]>)

  (client examines the header)
  C:      HEAD
  S:      221 10110 <[email protected]> article retrieved - head
          follows (text of the header appears here)
  S:      .

  (client wants to see the text body of the article)
  C:      BODY
  S:      222 10110 <[email protected]> article retrieved - body
          follows (body text here)
  S:      .

  (client selects next article in group)


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RFC 977                                                    February 1986
Network News Transfer Protocol


  C:      NEXT
  S:      223 10113 <[email protected]> article retrieved - statistics
          only (article 10113 was next in group)

  (client finishes session)
  C:      QUIT
  S:      205 goodbye.

4.2.  Example 2 - absolute article access with ARTICLE

  S:      (listens at TCP port 119)

  C:      (requests connection on TCP port 119)
  S:      201 UCB-VAX netnews server ready -- no posting allowed

  C:      GROUP msgs
  S:      211 103 402 504 msgs Your new group is msgs
          (there are 103 articles, from 402 to 504)

  C:      ARTICLE 401
  S:      423 No such article in this newsgroup

  C:      ARTICLE 402
  S:      220 402 <[email protected]> Article retrieved, text follows
  S:      (article header and body follow)
  S:      .

  C:      HEAD 403
  S:      221 403 <[email protected]> Article retrieved, header follows
  S:      (article header follows)
  S:      .

  C:      QUIT
  S:      205 UCB-VAX news server closing connection.  Goodbye.

4.3.  Example 3 - NEWGROUPS command

  S:      (listens at TCP port 119)

  C:      (requests connection on TCP port 119)
  S:      200 Imaginary Institute News Server ready (posting ok)

  (client asks for new newsgroups since April 3, 1985)
  C:      NEWGROUPS 850403 020000

  S:      231 New newsgroups since 03/04/85 02:00:00 follow



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RFC 977                                                    February 1986
Network News Transfer Protocol


  S:      net.music.gdead
  S:      net.games.sources
  S:      .

  C:      GROUP net.music.gdead
  S:      211 0 1 1 net.music.gdead Newsgroup selected
          (there are no articles in that newsgroup, and
          the first and last article numbers should be ignored)

  C:      QUIT
  S:      205 Imaginary Institute news server ceasing service.  Bye!

4.4.  Example 4 - posting a news article

  S:      (listens at TCP port 119)

  C:      (requests connection on TCP port 119)
  S:      200 BANZAIVAX news server ready, posting allowed.

  C:      POST
  S:      340 Continue posting; Period on a line by itself to end
  C:      (transmits news article in RFC850 format)
  C:      .
  S:      240 Article posted successfully.

  C:      QUIT
  S:      205 BANZAIVAX closing connection.  Goodbye.

4.5.  Example 5 - interruption due to operator request

  S:      (listens at TCP port 119)

  C:      (requests connection on TCP port 119)
  S:      201 genericvax news server ready, no posting allowed.

          (assume normal conversation for some time, and
          that a newsgroup has been selected)

  C:      NEXT
  S:      223 1013 <[email protected]> Article retrieved; text separate.

  C:      HEAD
  C:      221 1013 <[email protected]> Article retrieved; head follows.

  S:      (sends head of article, but halfway through is
          interrupted by an operator request.  The following
          then occurs, without client intervention.)


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RFC 977                                                    February 1986
Network News Transfer Protocol


  S:      (ends current line with a CR-LF pair)
  S:      .
  S:      400 Connection closed by operator.  Goodbye.
  S:      (closes connection)

4.6.  Example 6 - Using the news server to distribute news between
     systems.

  S:      (listens at TCP port 119)

  C:      (requests connection on TCP port 119)
  S:      201 Foobar NNTP server ready (no posting)

  (client asks for new newsgroups since 2 am, May 15, 1985)
  C:      NEWGROUPS 850515 020000
  S:      235 New newsgroups since 850515 follow
  S:      net.fluff
  S:      net.lint
  S:      .

  (client asks for new news articles since 2 am, May 15, 1985)
  C:      NEWNEWS * 850515 020000
  S:      230 New news since 850515 020000 follows
  S:      <[email protected]>
  S:      <[email protected]>
  S:      <[email protected]>
  S:      .

  (client asks for article <[email protected]>)
  C:      ARTICLE <[email protected]>
  S:      220 <[email protected]> All of article follows
  S:      (sends entire message)
  S:      .

  (client asks for article <[email protected]>
  C:      ARTICLE <[email protected]>
  S:      220 <[email protected]> All of article follows
  S:      (sends entire message)
  S:      .

  (client asks for article <[email protected]>
  C:      ARTICLE <[email protected]>
  S:      220 <[email protected]> All of article follows
  S:      (sends entire message)
  S:      .




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RFC 977                                                    February 1986
Network News Transfer Protocol


  (client offers an article it has received recently)
  C:      IHAVE <[email protected]>
  S:      435 Already seen that one, where you been?

  (client offers another article)
  C:      IHAVE <[email protected]>
  S:      335 News to me!  <CRLF.CRLF> to end.
  C:      (sends article)
  C:      .
  S:      235 Article transferred successfully.  Thanks.

  (or)

  S:      436 Transfer failed.

  (client is all through with the session)
  C:      QUIT
  S:      205 Foobar NNTP server bids you farewell.

4.7.  Summary of commands and responses.

  The following are the commands recognized and responses returned by
  the NNTP server.

4.7.1.  Commands

  ARTICLE
  BODY
  GROUP
  HEAD
  HELP
  IHAVE
  LAST
  LIST
  NEWGROUPS
  NEWNEWS
  NEXT
  POST
  QUIT
  SLAVE
  STAT

4.7.2.  Responses

  100 help text follows
  199 debug output



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RFC 977                                                    February 1986
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

4.8.  A Brief Word about the USENET News System

  In the UNIX world, which traditionally has been linked by 1200 baud
  dial-up telephone lines, the USENET News system has evolved to handle
  central storage, indexing, retrieval, and distribution of news.  With
  the exception of its underlying transport mechanism (UUCP), USENET
  News is an efficient means of providing news and bulletin service to
  subscribers on UNIX and other hosts worldwide.  The USENET News




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RFC 977                                                    February 1986
Network News Transfer Protocol


  system is discussed in detail in RFC 850.  It runs on most versions
  of UNIX and on many other operating systems, and is customarily
  distributed without charge.

  USENET uses a spooling area on the UNIX host to store news articles,
  one per file. Each article consists of a series of heading text,
  which contain the sender's identification and organizational
  affiliation, timestamps, electronic mail reply paths, subject,
  newsgroup (subject category), and the like.  A complete news article
  is reproduced in its entirety below.  Please consult RFC 850 for more
  details.

     Relay-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site
     sdcsvax.UUCP
     Posting-Version: version B 2.10.1 6/24/83 SMI; site unitek.uucp
     Path:sdcsvax!sdcrdcf!hplabs!qantel!ihnp4!alberta!ubc-vision!unitek
     !honman
     From: [email protected] (Man Wong)
     Newsgroups: net.unix-wizards
     Subject: foreground -> background ?
     Message-ID: <[email protected]>
     Date: 25 Sep 85 23:51:52 GMT
     Date-Received: 29 Sep 85 09:54:48 GMT
     Reply-To: [email protected] (Hon-Man Wong)
     Distribution: net.all
     Organization: Unitek Technologies Corporation
     Lines: 12

     I have a process (C program) which generates a child and waits for
     it to return.  What I would like to do is to be able to run the
     child process interactively for a while before kicking itself into
     the background so I can return to the parent process (while the
     child process is RUNNING in the background).  Can it be done?  And
     if it can, how?

     Please reply by E-mail.  Thanks in advance.

     Hon-Man Wong











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RFC 977                                                    February 1986
Network News Transfer Protocol


5.  References

  [1]  Crocker, D., "Standard for the Format of ARPA Internet Text
       Messages", RFC-822, Department of Electrical Engineering,
       University of Delaware, August, 1982.

  [2]  Horton, M., "Standard for Interchange of USENET Messages",
       RFC-850, USENET Project, June, 1983.

  [3]  Postel, J., "Transmission Control Protocol- DARPA Internet
       Program Protocol Specification", RFC-793, USC/Information
       Sciences Institute, September, 1981.

  [4]  Postel, J., "Simple Mail Transfer Protocol", RFC-821,
       USC/Information Sciences Institute, August, 1982.

6.  Acknowledgements

  The authors wish to express their heartfelt thanks to those many
  people who contributed to this specification, and especially to Erik
  Fair and Chuq von Rospach, without whose inspiration this whole thing
  would not have been necessary.

7.  Notes

  <1> UNIX is a trademark of Bell Laboratories.























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