rsalz@bbn.com (Rich Salz) (04/21/88)
Submitted-by: Phil Lapsley <phil@ucbvax.berkeley.edu>
Posting-number: Volume 14, Issue 55
Archive-name: nntp1.5/part09
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X
X
Network Working Group Brian Kantor (U.C. San Diego)
Request for Comments: 977 Phil Lapsley (U.C. Berkeley)
X February 1986
X
X Network News Transfer Protocol
X
X A Proposed Standard for the Stream-Based
X Transmission of News
X
Status of This Memo
X
X NNTP specifies a protocol for the distribution, inquiry, retrieval,
X and posting of news articles using a reliable stream-based
X transmission of news among the ARPA-Internet community. NNTP is
X designed so that news articles are stored in a central database
X allowing a subscriber to select only those items he wishes to read.
X Indexing, cross-referencing, and expiration of aged messages are also
X provided. This RFC suggests a proposed protocol for the ARPA-Internet
X community, and requests discussion and suggestions for improvements.
X Distribution of this memo is unlimited.
X
X1. Introduction
X
X For many years, the ARPA-Internet community has supported the
X distribution of bulletins, information, and data in a timely fashion
X to thousands of participants. We collectively refer to such items of
X information as "news". Such news provides for the rapid
X dissemination of items of interest such as software bug fixes, new
X product reviews, technical tips, and programming pointers, as well as
X rapid-fire discussions of matters of concern to the working computer
X professional. News is very popular among its readers.
X
X There are popularly two methods of distributing such news: the
X Internet method of direct mailing, and the USENET news system.
X
X1.1. Internet Mailing Lists
X
X The Internet community distributes news by the use of mailing lists.
X These are lists of subscriber's mailbox addresses and remailing
X sublists of all intended recipients. These mailing lists operate by
X remailing a copy of the information to be distributed to each
X subscriber on the mailing list. Such remailing is inefficient when a
X mailing list grows beyond a dozen or so people, since sending a
X separate copy to each of the subscribers occupies large quantities of
X network bandwidth, CPU resources, and significant amounts of disk
X storage at the destination host. There is also a significant problem
X in maintenance of the list itself: as subscribers move from one job
X to another; as new subscribers join and old ones leave; and as hosts
X come in and out of service.
X
X
X
X
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X1.2. The USENET News System
X
X Clearly, a worthwhile reduction of the amount of these resources used
X can be achieved if articles are stored in a central database on the
X receiving host instead of in each subscriber's mailbox. The USENET
X news system provides a method of doing just this. There is a central
X repository of the news articles in one place (customarily a spool
X directory of some sort), and a set of programs that allow a
X subscriber to select those items he wishes to read. Indexing,
X cross-referencing, and expiration of aged messages are also provided.
X
X1.3. Central Storage of News
X
X For clusters of hosts connected together by fast local area networks
X (such as Ethernet), it makes even more sense to consolidate news
X distribution onto one (or a very few) hosts, and to allow access to
X these news articles using a server and client model. Subscribers may
X then request only the articles they wish to see, without having to
X wastefully duplicate the storage of a copy of each item on each host.
X
X1.4. A Central News Server
X
X A way to achieve these economies is to have a central computer system
X that can provide news service to the other systems on the local area
X network. Such a server would manage the collection of news articles
X and index files, with each person who desires to read news bulletins
X doing so over the LAN. For a large cluster of computer systems, the
X savings in total disk space is clearly worthwhile. Also, this allows
X workstations with limited disk storage space to participate in the
X news without incoming items consuming oppressive amounts of the
X workstation's disk storage.
X
X We have heard rumors of somewhat successful attempts to provide
X centralized news service using IBIS and other shared or distributed
X file systems. While it is possible that such a distributed file
X system implementation might work well with a group of similar
X computers running nearly identical operating systems, such a scheme
X is not general enough to offer service to a wide range of client
X systems, especially when many diverse operating systems may be in use
X among a group of clients. There are few (if any) shared or networked
X file systems that can offer the generality of service that stream
X connections using Internet TCP provide, particularly when a wide
X range of host hardware and operating systems are considered.
X
X NNTP specifies a protocol for the distribution, inquiry, retrieval,
X and posting of news articles using a reliable stream (such as TCP)
X server-client model. NNTP is designed so that news articles need only
X
X
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RFC 977 February 1986
Network News Transfer Protocol
X
X
X be stored on one (presumably central) host, and subscribers on other
X hosts attached to the LAN may read news articles using stream
X connections to the news host.
X
X NNTP is modelled upon the news article specifications in RFC 850,
X which describes the USENET news system. However, NNTP makes few
X demands upon the structure, content, or storage of news articles, and
X thus we believe it easily can be adapted to other non-USENET news
X systems.
X
X Typically, the NNTP server runs as a background process on one host,
X and would accept connections from other hosts on the LAN. This works
X well when there are a number of small computer systems (such as
X workstations, with only one or at most a few users each), and a large
X central server.
X
X1.5. Intermediate News Servers
X
X For clusters of machines with many users (as might be the case in a
X university or large industrial environment), an intermediate server
X might be used. This intermediate or "slave" server runs on each
X computer system, and is responsible for mediating news reading
X requests and performing local caching of recently-retrieved news
X articles.
X
X Typically, a client attempting to obtain news service would first
X attempt to connect to the news service port on the local machine. If
X this attempt were unsuccessful, indicating a failed server, an
X installation might choose to either deny news access, or to permit
X connection to the central "master" news server.
X
X For workstations or other small systems, direct connection to the
X master server would probably be the normal manner of operation.
X
X This specification does not cover the operation of slave NNTP
X servers. We merely suggest that slave servers are a logical addition
X to NNTP server usage which would enhance operation on large local
X area networks.
X
X1.6. News Distribution
X
X NNTP has commands which provide a straightforward method of
X exchanging articles between cooperating hosts. Hosts which are well
X connected on a local area or other fast network and who wish to
X actually obtain copies of news articles for local storage might well
X find NNTP to be a more efficient way to distribute news than more
X traditional transfer methods (such as UUCP).
X
X
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RFC 977 February 1986
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X
X In the traditional method of distributing news articles, news is
X propagated from host to host by flooding - that is, each host will
X send all its new news articles on to each host that it feeds. These
X hosts will then in turn send these new articles on to other hosts
X that they feed. Clearly, sending articles that a host already has
X obtained a copy of from another feed (many hosts that receive news
X are redundantly fed) again is a waste of time and communications
X resources, but for transport mechanisms that are single-transaction
X based rather than interactive (such as UUCP in the UNIX-world <1>),
X distribution time is diminished by sending all articles and having
X the receiving host simply discard the duplicates. This is an
X especially true when communications sessions are limited to once a
X day.
X
X Using NNTP, hosts exchanging news articles have an interactive
X mechanism for deciding which articles are to be transmitted. A host
X desiring new news, or which has new news to send, will typically
X contact one or more of its neighbors using NNTP. First it will
X inquire if any new news groups have been created on the serving host
X by means of the NEWGROUPS command. If so, and those are appropriate
X or desired (as established by local site-dependent rules), those new
X newsgroups can be created.
X
X The client host will then inquire as to which new articles have
X arrived in all or some of the newsgroups that it desires to receive,
X using the NEWNEWS command. It will receive a list of new articles
X from the server, and can request transmission of those articles that
X it desires and does not already have.
X
X Finally, the client can advise the server of those new articles which
X the client has recently received. The server will indicate those
X articles that it has already obtained copies of, and which articles
X should be sent to add to its collection.
X
X In this manner, only those articles which are not duplicates and
X which are desired are transferred.
X
X
X
X
X
X
X
X
X
X
X
X
X
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X
X2. The NNTP Specification
X
X2.1. Overview
X
X The news server specified by this document uses a stream connection
X (such as TCP) and SMTP-like commands and responses. It is designed
X to accept connections from hosts, and to provide a simple interface
X to the news database.
X
X This server is only an interface between programs and the news
X databases. It does not perform any user interaction or presentation-
X level functions. These "user-friendly" functions are better left to
X the client programs, which have a better understanding of the
X environment in which they are operating.
X
X When used via Internet TCP, the contact port assigned for this
X service is 119.
X
X2.2. Character Codes
X
X Commands and replies are composed of characters from the ASCII
X character set. When the transport service provides an 8-bit byte
X (octet) transmission channel, each 7-bit character is transmitted
X right justified in an octet with the high order bit cleared to zero.
X
X2.3. Commands
X
X Commands consist of a command word, which in some cases may be
X followed by a parameter. Commands with parameters must separate the
X parameters from each other and from the command by one or more space
X or tab characters. Command lines must be complete with all required
X parameters, and may not contain more than one command.
X
X Commands and command parameters are not case sensitive. That is, a
X command or parameter word may be upper case, lower case, or any
X mixture of upper and lower case.
X
X Each command line must be terminated by a CR-LF (Carriage Return -
X Line Feed) pair.
X
X Command lines shall not exceed 512 characters in length, counting all
X characters including spaces, separators, punctuation, and the
X trailing CR-LF (thus there are 510 characters maximum allowed for the
X command and its parameters). There is no provision for continuation
X command lines.
X
X
X
X
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X
X2.4. Responses
X
X Responses are of two kinds, textual and status.
X
X2.4.1. Text Responses
X
X Text is sent only after a numeric status response line has been sent
X that indicates that text will follow. Text is sent as a series of
X successive lines of textual matter, each terminated with CR-LF pair.
X A single line containing only a period (.) is sent to indicate the
X end of the text (i.e., the server will send a CR-LF pair at the end
X of the last line of text, a period, and another CR-LF pair).
X
X If the text contained a period as the first character of the text
X line in the original, that first period is doubled. Therefore, the
X client must examine the first character of each line received, and
X for those beginning with a period, determine either that this is the
X end of the text or whether to collapse the doubled period to a single
X one.
X
X The intention is that text messages will usually be displayed on the
X user's terminal whereas command/status responses will be interpreted
X by the client program before any possible display is done.
X
X2.4.2. Status Responses
X
X These are status reports from the server and indicate the response to
X the last command received from the client.
X
X Status response lines begin with a 3 digit numeric code which is
X sufficient to distinguish all responses. Some of these may herald
X the subsequent transmission of text.
X
X The first digit of the response broadly indicates the success,
X failure, or progress of the previous command.
X
X 1xx - Informative message
X 2xx - Command ok
X 3xx - Command ok so far, send the rest of it.
X 4xx - Command was correct, but couldn't be performed for
X some reason.
X 5xx - Command unimplemented, or incorrect, or a serious
X program error occurred.
X
X
X
X
X
X
Kantor & Lapsley [Page 6]
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RFC 977 February 1986
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X
X The next digit in the code indicates the function response category.
X
X x0x - Connection, setup, and miscellaneous messages
X x1x - Newsgroup selection
X x2x - Article selection
X x3x - Distribution functions
X x4x - Posting
X x8x - Nonstandard (private implementation) extensions
X x9x - Debugging output
X
X The exact response codes that should be expected from each command
X are detailed in the description of that command. In addition, below
X is listed a general set of response codes that may be received at any
X time.
X
X Certain status responses contain parameters such as numbers and
X names. The number and type of such parameters is fixed for each
X response code to simplify interpretation of the response.
X
X Parameters are separated from the numeric response code and from each
X other by a single space. All numeric parameters are decimal, and may
X have leading zeros. All string parameters begin after the separating
X space, and end before the following separating space or the CR-LF
X pair at the end of the line. (String parameters may not, therefore,
X contain spaces.) All text, if any, in the response which is not a
X parameter of the response must follow and be separated from the last
X parameter by a space. Also, note that the text following a response
X number may vary in different implementations of the server. The
X 3-digit numeric code should be used to determine what response was
X sent.
X
X Response codes not specified in this standard may be used for any
X installation-specific additional commands also not specified. These
X should be chosen to fit the pattern of x8x specified above. (Note
X that debugging is provided for explicitly in the x9x response codes.)
X The use of unspecified response codes for standard commands is
X prohibited.
X
X We have provided a response pattern x9x for debugging. Since much
X debugging output may be classed as "informative messages", we would
X expect, therefore, that responses 190 through 199 would be used for
X various debugging outputs. There is no requirement in this
X specification for debugging output, but if such is provided over the
X connected stream, it must use these response codes. If appropriate
X to a specific implementation, other x9x codes may be used for
X debugging. (An example might be to use e.g., 290 to acknowledge a
X remote debugging request.)
X
X
Kantor & Lapsley [Page 7]
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RFC 977 February 1986
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X
X
X2.4.3. General Responses
X
X The following is a list of general response codes that may be sent by
X the NNTP server. These are not specific to any one command, but may
X be returned as the result of a connection, a failure, or some unusual
X condition.
X
X In general, 1xx codes may be ignored or displayed as desired; code
X 200 or 201 is sent upon initial connection to the NNTP server
X depending upon posting permission; code 400 will be sent when the
X NNTP server discontinues service (by operator request, for example);
X and 5xx codes indicate that the command could not be performed for
X some unusual reason.
X
X 100 help text
X 190
X through
X 199 debug output
X
X 200 server ready - posting allowed
X 201 server ready - no posting allowed
X
X 400 service discontinued
X
X 500 command not recognized
X 501 command syntax error
X 502 access restriction or permission denied
X 503 program fault - command not performed
X
X3. Command and Response Details
X
X On the following pages are descriptions of each command recognized by
X the NNTP server and the responses which will be returned by those
X commands.
X
X Each command is shown in upper case for clarity, although case is
X ignored in the interpretation of commands by the NNTP server. Any
X parameters are shown in lower case. A parameter shown in [square
X brackets] is optional. For example, [GMT] indicates that the
X triglyph GMT may present or omitted.
X
X Every command described in this section must be implemented by all
X NNTP servers.
X
X
X
X
X
X
Kantor & Lapsley [Page 8]
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RFC 977 February 1986
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X
X There is no prohibition against additional commands being added;
X however, it is recommended that any such unspecified command begin
X with the letter "X" to avoid conflict with later revisions of this
X specification.
X
X Implementors are reminded that such additional commands may not
X redefine specified status response codes. Using additional
X unspecified responses for standard commands is also prohibited.
X
X3.1. The ARTICLE, BODY, HEAD, and STAT commands
X
X There are two forms to the ARTICLE command (and the related BODY,
X HEAD, and STAT commands), each using a different method of specifying
X which article is to be retrieved. When the ARTICLE command is
X followed by a message-id in angle brackets ("<" and ">"), the first
X form of the command is used; when a numeric parameter or no parameter
X is supplied, the second form is invoked.
X
X The text of the article is returned as a textual response, as
X described earlier in this document.
X
X The HEAD and BODY commands are identical to the ARTICLE command
X except that they respectively return only the header lines or text
X body of the article.
X
X The STAT command is similar to the ARTICLE command except that no
X text is returned. When selecting by message number within a group,
X the STAT command serves to set the current article pointer without
X sending text. The returned acknowledgement response will contain the
X message-id, which may be of some value. Using the STAT command to
X select by message-id is valid but of questionable value, since a
X selection by message-id does NOT alter the "current article pointer".
X
X3.1.1. ARTICLE (selection by message-id)
X
X ARTICLE <message-id>
X
X Display the header, a blank line, then the body (text) of the
X specified article. Message-id is the message id of an article as
X shown in that article's header. It is anticipated that the client
X will obtain the message-id from a list provided by the NEWNEWS
X command, from references contained within another article, or from
X the message-id provided in the response to some other commands.
X
X Please note that the internally-maintained "current article pointer"
X is NOT ALTERED by this command. This is both to facilitate the
X presentation of articles that may be referenced within an article
X
X
Kantor & Lapsley [Page 9]
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X
X
X being read, and because of the semantic difficulties of determining
X the proper sequence and membership of an article which may have been
X posted to more than one newsgroup.
X
X3.1.2. ARTICLE (selection by number)
X
X ARTICLE [nnn]
X
X Displays the header, a blank line, then the body (text) of the
X current or specified article. The optional parameter nnn is the
X
X numeric id of an article in the current newsgroup and must be chosen
X from the range of articles provided when the newsgroup was selected.
X If it is omitted, the current article is assumed.
X
X The internally-maintained "current article pointer" is set by this
X command if a valid article number is specified.
X
X [the following applies to both forms of the article command.] A
X response indicating the current article number, a message-id string,
X and that text is to follow will be returned.
X
X The message-id string returned is an identification string contained
X within angle brackets ("<" and ">"), which is derived from the header
X of the article itself. The Message-ID header line (required by
X RFC850) from the article must be used to supply this information. If
X the message-id header line is missing from the article, a single
X digit "0" (zero) should be supplied within the angle brackets.
X
X Since the message-id field is unique with each article, it may be
X used by a news reading program to skip duplicate displays of articles
X that have been posted more than once, or to more than one newsgroup.
X
X3.1.3. Responses
X
X 220 n <a> article retrieved - head and body follow
X (n = article number, <a> = message-id)
X 221 n <a> article retrieved - head follows
X 222 n <a> article retrieved - body follows
X 223 n <a> article retrieved - request text separately
X 412 no newsgroup has been selected
X 420 no current article has been selected
X 423 no such article number in this group
X 430 no such article found
X
X
X
X
X
Kantor & Lapsley [Page 10]
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RFC 977 February 1986
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X
X3.2. The GROUP command
X
X3.2.1. GROUP
X
X GROUP ggg
X
X The required parameter ggg is the name of the newsgroup to be
X selected (e.g. "net.news"). A list of valid newsgroups may be
X obtained from the LIST command.
X
X The successful selection response will return the article numbers of
X the first and last articles in the group, and an estimate of the
X number of articles on file in the group. It is not necessary that
X the estimate be correct, although that is helpful; it must only be
X equal to or larger than the actual number of articles on file. (Some
X implementations will actually count the number of articles on file.
X Others will just subtract first article number from last to get an
X estimate.)
X
X When a valid group is selected by means of this command, the
X internally maintained "current article pointer" is set to the first
X article in the group. If an invalid group is specified, the
X previously selected group and article remain selected. If an empty
X newsgroup is selected, the "current article pointer" is in an
X indeterminate state and should not be used.
X
X Note that the name of the newsgroup is not case-dependent. It must
X otherwise match a newsgroup obtained from the LIST command or an
X error will result.
X
X3.2.2. Responses
X
X 211 n f l s group selected
X (n = estimated number of articles in group,
X f = first article number in the group,
X l = last article number in the group,
X s = name of the group.)
X 411 no such news group
X
X
X
X
X
X
X
X
X
X
X
Kantor & Lapsley [Page 11]
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RFC 977 February 1986
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X
X3.3. The HELP command
X
X3.3.1. HELP
X
X HELP
X
X Provides a short summary of commands that are understood by this
X implementation of the server. The help text will be presented as a
X textual response, terminated by a single period on a line by itself.
X
X 3.3.2. Responses
X
X 100 help text follows
X
X3.4. The IHAVE command
X
X3.4.1. IHAVE
X
X IHAVE <messageid>
X
X The IHAVE command informs the server that the client has an article
X whose id is <messageid>. If the server desires a copy of that
X article, it will return a response instructing the client to send the
X entire article. If the server does not want the article (if, for
X example, the server already has a copy of it), a response indicating
X that the article is not wanted will be returned.
X
X If transmission of the article is requested, the client should send
X the entire article, including header and body, in the manner
X specified for text transmission from the server. A response code
X indicating success or failure of the transferral of the article will
X be returned.
X
X This function differs from the POST command in that it is intended
X for use in transferring already-posted articles between hosts.
X Normally it will not be used when the client is a personal
X newsreading program. In particular, this function will invoke the
X server's news posting program with the appropriate settings (flags,
X options, etc) to indicate that the forthcoming article is being
X forwarded from another host.
X
X The server may, however, elect not to post or forward the article if
X after further examination of the article it deems it inappropriate to
X do so. The 436 or 437 error codes may be returned as appropriate to
X the situation.
X
X Reasons for such subsequent rejection of an article may include such
X
X
Kantor & Lapsley [Page 12]
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X
X problems as inappropriate newsgroups or distributions, disk space
X limitations, article lengths, garbled headers, and the like. These
X are typically restrictions enforced by the server host's news
X software and not necessarily the NNTP server itself.
X
X3.4.2. Responses
X
X 235 article transferred ok
X 335 send article to be transferred. End with <CR-LF>.<CR-LF>
X 435 article not wanted - do not send it
X 436 transfer failed - try again later
X 437 article rejected - do not try again
X
X An implementation note:
X
X Because some host news posting software may not be able to decide
X immediately that an article is inappropriate for posting or
X forwarding, it is acceptable to acknowledge the successful transfer
X of the article and to later silently discard it. Thus it is
X permitted to return the 235 acknowledgement code and later discard
X the received article. This is not a fully satisfactory solution to
X the problem. Perhaps some implementations will wish to send mail to
X the author of the article in certain of these cases.
X
X3.5. The LAST command
X
X3.5.1. LAST
X
X LAST
X
X The internally maintained "current article pointer" is set to the
X previous article in the current newsgroup. If already positioned at
X the first article of the newsgroup, an error message is returned and
X the current article remains selected.
X
X The internally-maintained "current article pointer" is set by this
X command.
X
X A response indicating the current article number, and a message-id
X string will be returned. No text is sent in response to this
X command.
X
X3.5.2. Responses
X
X 223 n a article retrieved - request text separately
X (n = article number, a = unique article id)
X
X
X
Kantor & Lapsley [Page 13]
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RFC 977 February 1986
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X
X 412 no newsgroup selected
X 420 no current article has been selected
X 422 no previous article in this group
X
X3.6. The LIST command
X
X3.6.1. LIST
X
X LIST
X
X Returns a list of valid newsgroups and associated information. Each
X newsgroup is sent as a line of text in the following format:
X
X group last first p
X
X where <group> is the name of the newsgroup, <last> is the number of
X the last known article currently in that newsgroup, <first> is the
X number of the first article currently in the newsgroup, and <p> is
X either 'y' or 'n' indicating whether posting to this newsgroup is
X allowed ('y') or prohibited ('n').
X
X The <first> and <last> fields will always be numeric. They may have
X leading zeros. If the <last> field evaluates to less than the
X <first> field, there are no articles currently on file in the
X newsgroup.
X
X Note that posting may still be prohibited to a client even though the
X LIST command indicates that posting is permitted to a particular
X newsgroup. See the POST command for an explanation of client
X prohibitions. The posting flag exists for each newsgroup because
X some newsgroups are moderated or are digests, and therefore cannot be
X posted to; that is, articles posted to them must be mailed to a
X moderator who will post them for the submitter. This is independent
X of the posting permission granted to a client by the NNTP server.
X
X Please note that an empty list (i.e., the text body returned by this
X command consists only of the terminating period) is a possible valid
X response, and indicates that there are currently no valid newsgroups.
X
X3.6.2. Responses
X
X 215 list of newsgroups follows
X
X
X
X
X
X
X
Kantor & Lapsley [Page 14]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X3.7. The NEWGROUPS command
X
X3.7.1. NEWGROUPS
X
X NEWGROUPS date time [GMT] [<distributions>]
X
X A list of newsgroups created since <date and time> will be listed in
X the same format as the LIST command.
X
X The date is sent as 6 digits in the format YYMMDD, where YY is the
X last two digits of the year, MM is the two digits of the month (with
X leading zero, if appropriate), and DD is the day of the month (with
X leading zero, if appropriate). The closest century is assumed as
X part of the year (i.e., 86 specifies 1986, 30 specifies 2030, 99 is
X 1999, 00 is 2000).
X
X Time must also be specified. It must be as 6 digits HHMMSS with HH
X being hours on the 24-hour clock, MM minutes 00-59, and SS seconds
X 00-59. The time is assumed to be in the server's timezone unless the
X token "GMT" appears, in which case both time and date are evaluated
X at the 0 meridian.
X
X The optional parameter "distributions" is a list of distribution
X groups, enclosed in angle brackets. If specified, the distribution
X portion of a new newsgroup (e.g, 'net' in 'net.wombat') will be
X examined for a match with the distribution categories listed, and
X only those new newsgroups which match will be listed. If more than
X one distribution group is to be listed, they must be separated by
X commas within the angle brackets.
X
X Please note that an empty list (i.e., the text body returned by this
X command consists only of the terminating period) is a possible valid
X response, and indicates that there are currently no new newsgroups.
X
X3.7.2. Responses
X
X 231 list of new newsgroups follows
X
X
X
X
X
X
X
X
X
X
X
X
Kantor & Lapsley [Page 15]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X3.8. The NEWNEWS command
X
X3.8.1. NEWNEWS
X
X NEWNEWS newsgroups date time [GMT] [<distribution>]
X
X A list of message-ids of articles posted or received to the specified
X newsgroup since "date" will be listed. The format of the listing will
X be one message-id per line, as though text were being sent. A single
X line consisting solely of one period followed by CR-LF will terminate
X the list.
X
X Date and time are in the same format as the NEWGROUPS command.
X
X A newsgroup name containing a "*" (an asterisk) may be specified to
X broaden the article search to some or all newsgroups. The asterisk
X will be extended to match any part of a newsgroup name (e.g.,
X net.micro* will match net.micro.wombat, net.micro.apple, etc). Thus
X if only an asterisk is given as the newsgroup name, all newsgroups
X will be searched for new news.
X
X (Please note that the asterisk "*" expansion is a general
X replacement; in particular, the specification of e.g., net.*.unix
X should be correctly expanded to embrace names such as net.wombat.unix
X and net.whocares.unix.)
X
X Conversely, if no asterisk appears in a given newsgroup name, only
X the specified newsgroup will be searched for new articles. Newsgroup
X names must be chosen from those returned in the listing of available
X groups. Multiple newsgroup names (including a "*") may be specified
X in this command, separated by a comma. No comma shall appear after
X the last newsgroup in the list. [Implementors are cautioned to keep
X the 512 character command length limit in mind.]
X
X The exclamation point ("!") may be used to negate a match. This can
X be used to selectively omit certain newsgroups from an otherwise
X larger list. For example, a newsgroups specification of
X "net.*,mod.*,!mod.map.*" would specify that all net.<anything> and
X all mod.<anything> EXCEPT mod.map.<anything> newsgroup names would be
X matched. If used, the exclamation point must appear as the first
X character of the given newsgroup name or pattern.
X
X The optional parameter "distributions" is a list of distribution
X groups, enclosed in angle brackets. If specified, the distribution
X portion of an article's newsgroup (e.g, 'net' in 'net.wombat') will
X be examined for a match with the distribution categories listed, and
X only those articles which have at least one newsgroup belonging to
X
X
Kantor & Lapsley [Page 16]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X the list of distributions will be listed. If more than one
X distribution group is to be supplied, they must be separated by
X commas within the angle brackets.
X
X The use of the IHAVE, NEWNEWS, and NEWGROUPS commands to distribute
X news is discussed in an earlier part of this document.
X
X Please note that an empty list (i.e., the text body returned by this
X command consists only of the terminating period) is a possible valid
X response, and indicates that there is currently no new news.
X
X3.8.2. Responses
X
X 230 list of new articles by message-id follows
X
X3.9. The NEXT command
X
X3.9.1. NEXT
X
X NEXT
X
X The internally maintained "current article pointer" is advanced to
X the next article in the current newsgroup. If no more articles
X remain in the current group, an error message is returned and the
X current article remains selected.
X
X The internally-maintained "current article pointer" is set by this
X command.
X
X A response indicating the current article number, and the message-id
X string will be returned. No text is sent in response to this
X command.
X
X3.9.2. Responses
X
X 223 n a article retrieved - request text separately
X (n = article number, a = unique article id)
X 412 no newsgroup selected
X 420 no current article has been selected
X 421 no next article in this group
X
X
X
X
X
X
X
X
X
Kantor & Lapsley [Page 17]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X3.10. The POST command
X
X3.10.1. POST
X
X POST
X
X If posting is allowed, response code 340 is returned to indicate that
X the article to be posted should be sent. Response code 440 indicates
X that posting is prohibited for some installation-dependent reason.
X
X If posting is permitted, the article should be presented in the
X format specified by RFC850, and should include all required header
X lines. After the article's header and body have been completely sent
X by the client to the server, a further response code will be returned
X to indicate success or failure of the posting attempt.
X
X The text forming the header and body of the message to be posted
X should be sent by the client using the conventions for text received
X from the news server: A single period (".") on a line indicates the
X end of the text, with lines starting with a period in the original
X text having that period doubled during transmission.
X
X No attempt shall be made by the server to filter characters, fold or
X limit lines, or otherwise process incoming text. It is our intent
X that the server just pass the incoming message to be posted to the
X server installation's news posting software, which is separate from
X this specification. See RFC850 for more details.
X
X Since most installations will want the client news program to allow
X the user to prepare his message using some sort of text editor, and
X transmit it to the server for posting only after it is composed, the
X client program should take note of the herald message that greeted it
X when the connection was first established. This message indicates
X whether postings from that client are permitted or not, and can be
X used to caution the user that his access is read-only if that is the
X case. This will prevent the user from wasting a good deal of time
X composing a message only to find posting of the message was denied.
X The method and determination of which clients and hosts may post is
X installation dependent and is not covered by this specification.
X
X3.10.2. Responses
X
X 240 article posted ok
X 340 send article to be posted. End with <CR-LF>.<CR-LF>
X 440 posting not allowed
X 441 posting failed
X
X
X
Kantor & Lapsley [Page 18]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X (for reference, one of the following codes will be sent upon initial
X connection; the client program should determine whether posting is
X generally permitted from these:) 200 server ready - posting allowed
X 201 server ready - no posting allowed
X
X3.11. The QUIT command
X
X3.11.1. QUIT
X
X QUIT
X
X The server process acknowledges the QUIT command and then closes the
X connection to the client. This is the preferred method for a client
X to indicate that it has finished all its transactions with the NNTP
X server.
X
X If a client simply disconnects (or the connection times out, or some
X other fault occurs), the server should gracefully cease its attempts
X to service the client.
X
X3.11.2. Responses
X
X 205 closing connection - goodbye!
X
X3.12. The SLAVE command
X
X3.12.1. SLAVE
X
X SLAVE
X
X Indicates to the server that this client connection is to a slave
X server, rather than a user.
X
X This command is intended for use in separating connections to single
X users from those to subsidiary ("slave") servers. It may be used to
X indicate that priority should therefore be given to requests from
X this client, as it is presumably serving more than one person. It
X might also be used to determine which connections to close when
X system load levels are exceeded, perhaps giving preference to slave
X servers. The actual use this command is put to is entirely
X implementation dependent, and may vary from one host to another. In
X NNTP servers which do not give priority to slave servers, this
X command must nonetheless be recognized and acknowledged.
X
X3.12.2. Responses
X
X 202 slave status noted
X
X
Kantor & Lapsley [Page 19]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X4. Sample Conversations
X
X These are samples of the conversations that might be expected with
X the news server in hypothetical sessions. The notation C: indicates
X commands sent to the news server from the client program; S: indicate
X responses received from the server by the client.
X
X4.1. Example 1 - relative access with NEXT
X
X S: (listens at TCP port 119)
X
X C: (requests connection on TCP port 119)
X S: 200 wombatvax news server ready - posting ok
X
X (client asks for a current newsgroup list)
X C: LIST
X S: 215 list of newsgroups follows
X S: net.wombats 00543 00501 y
X S: net.unix-wizards 10125 10011 y
X (more information here)
X S: net.idiots 00100 00001 n
X S: .
X
X (client selects a newsgroup)
X C: GROUP net.unix-wizards
X S: 211 104 10011 10125 net.unix-wizards group selected
X (there are 104 articles on file, from 10011 to 10125)
X
X (client selects an article to read)
X C: STAT 10110
X S: 223 10110 <23445@sdcsvax.ARPA> article retrieved - statistics
X only (article 10110 selected, its message-id is
X <23445@sdcsvax.ARPA>)
X
X (client examines the header)
X C: HEAD
X S: 221 10110 <23445@sdcsvax.ARPA> article retrieved - head
X follows (text of the header appears here)
X S: .
X
X (client wants to see the text body of the article)
X C: BODY
X S: 222 10110 <23445@sdcsvax.ARPA> article retrieved - body
X follows (body text here)
X S: .
X
X (client selects next article in group)
X
X
Kantor & Lapsley [Page 20]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X C: NEXT
X S: 223 10113 <21495@nudebch.uucp> article retrieved - statistics
X only (article 10113 was next in group)
X
X (client finishes session)
X C: QUIT
X S: 205 goodbye.
X
X4.2. Example 2 - absolute article access with ARTICLE
X
X S: (listens at TCP port 119)
X
X C: (requests connection on TCP port 119)
X S: 201 UCB-VAX netnews server ready -- no posting allowed
X
X C: GROUP msgs
X S: 211 103 402 504 msgs Your new group is msgs
X (there are 103 articles, from 402 to 504)
X
X C: ARTICLE 401
X S: 423 No such article in this newsgroup
X
X C: ARTICLE 402
X S: 220 402 <4105@ucbvax.ARPA> Article retrieved, text follows
X S: (article header and body follow)
X S: .
X
X C: HEAD 403
X S: 221 403 <3108@mcvax.UUCP> Article retrieved, header follows
X S: (article header follows)
X S: .
X
X C: QUIT
X S: 205 UCB-VAX news server closing connection. Goodbye.
X
X4.3. Example 3 - NEWGROUPS command
X
X S: (listens at TCP port 119)
X
X C: (requests connection on TCP port 119)
X S: 200 Imaginary Institute News Server ready (posting ok)
X
X (client asks for new newsgroups since April 3, 1985)
X C: NEWGROUPS 850403 020000
X
X S: 231 New newsgroups since 03/04/85 02:00:00 follow
X
X
X
Kantor & Lapsley [Page 21]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X S: net.music.gdead
X S: net.games.sources
X S: .
X
X C: GROUP net.music.gdead
X S: 211 0 1 1 net.music.gdead Newsgroup selected
X (there are no articles in that newsgroup, and
X the first and last article numbers should be ignored)
X
X C: QUIT
X S: 205 Imaginary Institute news server ceasing service. Bye!
X
X4.4. Example 4 - posting a news article
X
X S: (listens at TCP port 119)
X
X C: (requests connection on TCP port 119)
X S: 200 BANZAIVAX news server ready, posting allowed.
X
X C: POST
X S: 340 Continue posting; Period on a line by itself to end
X C: (transmits news article in RFC850 format)
X C: .
X S: 240 Article posted successfully.
X
X C: QUIT
X S: 205 BANZAIVAX closing connection. Goodbye.
X
X4.5. Example 5 - interruption due to operator request
X
X S: (listens at TCP port 119)
X
X C: (requests connection on TCP port 119)
X S: 201 genericvax news server ready, no posting allowed.
X
X (assume normal conversation for some time, and
X that a newsgroup has been selected)
X
X C: NEXT
X S: 223 1013 <5734@mcvax.UUCP> Article retrieved; text separate.
X
X C: HEAD
X C: 221 1013 <5734@mcvax.UUCP> Article retrieved; head follows.
X
X S: (sends head of article, but halfway through is
X interrupted by an operator request. The following
X then occurs, without client intervention.)
X
X
Kantor & Lapsley [Page 22]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X S: (ends current line with a CR-LF pair)
X S: .
X S: 400 Connection closed by operator. Goodbye.
X S: (closes connection)
X
X4.6. Example 6 - Using the news server to distribute news between
X systems.
X
X S: (listens at TCP port 119)
X
X C: (requests connection on TCP port 119)
X S: 201 Foobar NNTP server ready (no posting)
X
X (client asks for new newsgroups since 2 am, May 15, 1985)
X C: NEWGROUPS 850515 020000
X S: 235 New newsgroups since 850515 follow
X S: net.fluff
X S: net.lint
X S: .
X
X (client asks for new news articles since 2 am, May 15, 1985)
X C: NEWNEWS * 850515 020000
X S: 230 New news since 850515 020000 follows
X S: <1772@foo.UUCP>
X S: <87623@baz.UUCP>
X S: <17872@GOLD.CSNET>
X S: .
X
X (client asks for article <1772@foo.UUCP>)
X C: ARTICLE <1772@foo.UUCP>
X S: 220 <1772@foo.UUCP> All of article follows
X S: (sends entire message)
X S: .
X
X (client asks for article <87623@baz.UUCP>
X C: ARTICLE <87623@baz.UUCP>
X S: 220 <87623@baz.UUCP> All of article follows
X S: (sends entire message)
X S: .
X
X (client asks for article <17872@GOLD.CSNET>
X C: ARTICLE <17872@GOLD.CSNET>
X S: 220 <17872@GOLD.CSNET> All of article follows
X S: (sends entire message)
X S: .
X
X
X
X
Kantor & Lapsley [Page 23]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X (client offers an article it has received recently)
X C: IHAVE <4105@ucbvax.ARPA>
X S: 435 Already seen that one, where you been?
X
X (client offers another article)
X C: IHAVE <4106@ucbvax.ARPA>
X S: 335 News to me! <CRLF.CRLF> to end.
X C: (sends article)
X C: .
X S: 235 Article transferred successfully. Thanks.
X
X (or)
X
X S: 436 Transfer failed.
X
X (client is all through with the session)
X C: QUIT
X S: 205 Foobar NNTP server bids you farewell.
X
X4.7. Summary of commands and responses.
X
X The following are the commands recognized and responses returned by
X the NNTP server.
X
X4.7.1. Commands
X
X ARTICLE
X BODY
X GROUP
X HEAD
X HELP
X IHAVE
X LAST
X LIST
X NEWGROUPS
X NEWNEWS
X NEXT
X POST
X QUIT
X SLAVE
X STAT
X
X4.7.2. Responses
X
X 100 help text follows
X 199 debug output
X
X
X
Kantor & Lapsley [Page 24]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X 200 server ready - posting allowed
X 201 server ready - no posting allowed
X 202 slave status noted
X 205 closing connection - goodbye!
X 211 n f l s group selected
X 215 list of newsgroups follows
X 220 n <a> article retrieved - head and body follow 221 n <a> article
X retrieved - head follows
X 222 n <a> article retrieved - body follows
X 223 n <a> article retrieved - request text separately 230 list of new
X articles by message-id follows
X 231 list of new newsgroups follows
X 235 article transferred ok
X 240 article posted ok
X
X 335 send article to be transferred. End with <CR-LF>.<CR-LF>
X 340 send article to be posted. End with <CR-LF>.<CR-LF>
X
X 400 service discontinued
X 411 no such news group
X 412 no newsgroup has been selected
X 420 no current article has been selected
X 421 no next article in this group
X 422 no previous article in this group
X 423 no such article number in this group
X 430 no such article found
X 435 article not wanted - do not send it
X 436 transfer failed - try again later
X 437 article rejected - do not try again.
X 440 posting not allowed
X 441 posting failed
X
X 500 command not recognized
X 501 command syntax error
X 502 access restriction or permission denied
X 503 program fault - command not performed
X
X4.8. A Brief Word about the USENET News System
X
X In the UNIX world, which traditionally has been linked by 1200 baud
X dial-up telephone lines, the USENET News system has evolved to handle
X central storage, indexing, retrieval, and distribution of news. With
X the exception of its underlying transport mechanism (UUCP), USENET
X News is an efficient means of providing news and bulletin service to
X subscribers on UNIX and other hosts worldwide. The USENET News
X
X
X
X
Kantor & Lapsley [Page 25]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X system is discussed in detail in RFC 850. It runs on most versions
X of UNIX and on many other operating systems, and is customarily
X distributed without charge.
X
X USENET uses a spooling area on the UNIX host to store news articles,
X one per file. Each article consists of a series of heading text,
X which contain the sender's identification and organizational
X affiliation, timestamps, electronic mail reply paths, subject,
X newsgroup (subject category), and the like. A complete news article
X is reproduced in its entirety below. Please consult RFC 850 for more
X details.
X
X Relay-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site
X sdcsvax.UUCP
X Posting-Version: version B 2.10.1 6/24/83 SMI; site unitek.uucp
X Path:sdcsvax!sdcrdcf!hplabs!qantel!ihnp4!alberta!ubc-vision!unitek
X !honman
X From: honman@unitek.uucp (Man Wong)
X Newsgroups: net.unix-wizards
X Subject: foreground -> background ?
X Message-ID: <167@unitek.uucp>
X Date: 25 Sep 85 23:51:52 GMT
X Date-Received: 29 Sep 85 09:54:48 GMT
X Reply-To: honman@unitek.UUCP (Hon-Man Wong)
X Distribution: net.all
X Organization: Unitek Technologies Corporation
X Lines: 12
X
X I have a process (C program) which generates a child and waits for
X it to return. What I would like to do is to be able to run the
X child process interactively for a while before kicking itself into
X the background so I can return to the parent process (while the
X child process is RUNNING in the background). Can it be done? And
X if it can, how?
X
X Please reply by E-mail. Thanks in advance.
X
X Hon-Man Wong
X
X
X
X
X
X
X
X
X
X
X
Kantor & Lapsley [Page 26]
X
X
X
RFC 977 February 1986
Network News Transfer Protocol
X
X
X5. References
X
X [1] Crocker, D., "Standard for the Format of ARPA Internet Text
X Messages", RFC-822, Department of Electrical Engineering,
X University of Delaware, August, 1982.
X
X [2] Horton, M., "Standard for Interchange of USENET Messages",
X RFC-850, USENET Project, June, 1983.
X
X [3] Postel, J., "Transmission Control Protocol- DARPA Internet
X Program Protocol Specification", RFC-793, USC/Information
X Sciences Institute, September, 1981.
X
X [4] Postel, J., "Simple Mail Transfer Protocol", RFC-821,
X USC/Information Sciences Institute, August, 1982.
X
X6. Acknowledgements
X
X The authors wish to express their heartfelt thanks to those many
X people who contributed to this specification, and especially to Erik
X Fair and Chuq von Rospach, without whose inspiration this whole thing
X would not have been necessary.
X
X7. Notes
X
X <1> UNIX is a trademark of Bell Laboratories.
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Kantor & Lapsley [Page 27]
X
END_OF_FILE
if test 53523 -ne `wc -c <'./doc/rfc977'`; then
echo shar: \"'./doc/rfc977'\" unpacked with wrong size!
fi
# end of './doc/rfc977'
fi
echo shar: End of archive 9 \(of 9\).
cp /dev/null ark9isdone
MISSING=""
for I in 1 2 3 4 5 6 7 8 9 ; do
if test ! -f ark${I}isdone ; then
MISSING="${MISSING} ${I}"
fi
done
if test "${MISSING}" = "" ; then
echo You have unpacked all 9 archives.
rm -f ark[1-9]isdone ark[1-9][0-9]isdone
else
echo You still need to unpack the following archives:
echo " " ${MISSING}
fi
## End of shell archive.
exit 0
--
Please send comp.sources.unix-related mail to rsalz@uunet.uu.net.