 
  
 I Network Working Group                      Brian Kantor (U.C. San Diego)
 I Request for Comments: 977                   Phil Lapsley (U.C. Berkeley)
 I                                                            February 1986
  
 4                      Network News Transfer Protocol
%                                     
 9                 A Proposed Standard for the Stream-Based
 /                           Transmission of News
  
  Status of This Memo
 
 G    NNTP specifies a protocol for the distribution, inquiry, retrieval,
 >    and posting of news articles using a reliable stream-based
D    transmission of news among the ARPA-Internet community.  NNTP is
C    designed so that news articles are stored in a central database
 G    allowing a subscriber to select only those items he wishes to read.
 I    Indexing, cross-referencing, and expiration of aged messages are also
 I    provided. This RFC suggests a proposed protocol for the ARPA-Internet
 H    community, and requests discussion and suggestions for improvements.
+    Distribution of this memo is unlimited.
  
  1.  Introduction
  
 A    For many years, the ARPA-Internet community has supported the
 H    distribution of bulletins, information, and data in a timely fashion
I    to thousands of participants.  We collectively refer to such items of
 <    information as "news".  Such news provides for the rapid
F    dissemination of items of interest such as software bug fixes, new
I    product reviews, technical tips, and programming pointers, as well as
 H    rapid-fire discussions of matters of concern to the working computer
9    professional. News is very popular among its readers.
  
 B    There are popularly two methods of distributing such news: the
B    Internet method of direct mailing, and the USENET news system.
 
  1.1.  Internet Mailing Lists
  
 H    The Internet community distributes news by the use of mailing lists.
C    These are lists of subscriber's mailbox addresses and remailing
 H    sublists of all intended recipients.  These mailing lists operate by
A    remailing a copy of the information to be distributed to each
 I    subscriber on the mailing list.  Such remailing is inefficient when a
 C    mailing list grows beyond a dozen or so people, since sending a
 I    separate copy to each of the subscribers occupies large quantities of
 E    network bandwidth, CPU resources, and significant amounts of disk
 I    storage at the destination host.  There is also a significant problem
 G    in maintenance of the list itself: as subscribers move from one job
 H    to another; as new subscribers join and old ones leave; and as hosts
    come in and out of service.
  
  
  
  
 I Kantor & Lapsley                                                [Page 1]
  
 
  
 I RFC 977                                                    February 1986
  Network News Transfer Protocol
  
  
  1.2.  The USENET News System
  
 I    Clearly, a worthwhile reduction of the amount of these resources used
 G    can be achieved if articles are stored in a central database on the
 F    receiving host instead of in each subscriber's mailbox. The USENET
I    news system provides a method of doing just this.  There is a central
 E    repository of the news articles in one place (customarily a spool
 ?    directory of some sort), and a set of programs that allow a
 B    subscriber to select those items he wishes to read.  Indexing,
I    cross-referencing, and expiration of aged messages are also provided.
  
  1.3.  Central Storage of News
 
 H    For clusters of hosts connected together by fast local area networks
D    (such as Ethernet), it makes even more sense to consolidate news
G    distribution onto one (or a very few) hosts, and to allow access to
 I    these news articles using a server and client model.  Subscribers may
 F    then request only the articles they wish to see, without having to
I    wastefully duplicate the storage of a copy of each item on each host.
  
  1.4.  A Central News Server
 
 I    A way to achieve these economies is to have a central computer system
 H    that can provide news service to the other systems on the local area
H    network.  Such a server would manage the collection of news articles
H    and index files, with each person who desires to read news bulletins
H    doing so over the LAN.  For a large cluster of computer systems, the
I    savings in total disk space is clearly worthwhile.  Also, this allows
 F    workstations with limited disk storage space to participate in the
C    news without incoming items consuming oppressive amounts of the
     workstation's disk storage.
  
 C    We have heard rumors of somewhat successful attempts to provide
 G    centralized news service using IBIS and other shared or distributed
 D    file systems.  While it is possible that such a distributed file
A    system implementation might work well with a group of similar
 G    computers running nearly identical operating systems, such a scheme
 D    is not general enough to offer service to a wide range of client
I    systems, especially when many diverse operating systems may be in use
 I    among a group of clients.  There are few (if any) shared or networked
 E    file systems that can offer the generality of service that stream
 D    connections using Internet TCP provide, particularly when a wide
@    range of host hardware and operating systems are considered.
 
 G    NNTP specifies a protocol for the distribution, inquiry, retrieval,
 F    and posting of news articles using a reliable stream (such as TCP)
I    server-client model. NNTP is designed so that news articles need only
  
  
 I Kantor & Lapsley                                                [Page 2]
  
 
  
 I RFC 977                                                    February 1986
  Network News Transfer Protocol
  
  
 H    be stored on one (presumably central) host, and subscribers on other
A    hosts attached to the LAN may read news articles using stream
 !    connections to the news host.
  
 E    NNTP is modelled upon the news article specifications in RFC 850,
 D    which describes the USENET news system.  However, NNTP makes few
I    demands upon the structure, content, or storage of news articles, and
 E    thus we believe it easily can be adapted to other non-USENET news
     systems.
 
 H    Typically, the NNTP server runs as a background process on one host,
I    and would accept connections from other hosts on the LAN.  This works
 C    well when there are a number of small computer systems (such as
 I    workstations, with only one or at most a few users each), and a large
     central server.
  
   1.5.  Intermediate News Servers
 
 G    For clusters of machines with many users (as might be the case in a
 G    university or large industrial environment), an intermediate server
 D    might be used.  This intermediate or "slave" server runs on each
B    computer system, and is responsible for mediating news reading
D    requests and performing local caching of recently-retrieved news

    articles.
  
 E    Typically, a client attempting to obtain news service would first
 I    attempt to connect to the news service port on the local machine.  If
 B    this attempt were unsuccessful, indicating a failed server, an
F    installation might choose to either deny news access, or to permit
3    connection to the central "master" news server.
  
 E    For workstations or other small systems, direct connection to the
 C    master server would probably be the normal manner of operation.
  
 A    This specification does not cover the operation of slave NNTP
 I    servers.  We merely suggest that slave servers are a logical addition
 E    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
 G    exchanging articles between cooperating hosts. Hosts which are well
 C    connected on a local area or other fast network and who wish to
 H    actually obtain copies of news articles for local storage might well
E    find NNTP to be a more efficient way to distribute news than more
C0    traditional transfer methods (such as UUCP).
 
  
 I Kantor & Lapsley                                                [Page 3]
  
 
  
 I RFC 977                                                    February 1986
o Network News Transfer Protocol
  
  
 D    In the traditional method of distributing news articles, news is
F    propagated from host to host by flooding - that is, each host will
H    send all its new news articles on to each host that it feeds.  These
E    hosts will then in turn send these new articles on to other hosts
sF    that they feed.  Clearly, sending articles that a host already has
F    obtained a copy of from another feed (many hosts that receive news
D    are redundantly fed) again is a waste of time and communications
G    resources, but for transport mechanisms that are single-transaction
oG    based rather than interactive (such as UUCP in the UNIX-world <1>),
cF    distribution time is diminished by sending all articles and having
A    the receiving host simply discard the duplicates.  This is an
 F    especially true when communications sessions are limited to once a
    day.
 
oB    Using NNTP, hosts exchanging news articles have an interactive
H    mechanism for deciding which articles are to be transmitted.  A host
D    desiring new news, or which has new news to send, will typically
C    contact one or more of its neighbors using NNTP.  First it will
rH    inquire if any new news groups have been created on the serving host
H    by means of the NEWGROUPS command.  If so, and those are appropriate
H    or desired (as established by local site-dependent rules), those new
    newsgroups can be created.
 
 C    The client host will then inquire as to which new articles have
 H    arrived in all or some of the newsgroups that it desires to receive,
F    using the NEWNEWS command.  It will receive a list of new articles
H    from the server, and can request transmission of those articles that
)    it desires and does not already have.
b 
 I    Finally, the client can advise the server of those new articles which
cE    the client has recently received.  The server will indicate those
mG    articles that it has already obtained copies of, and which articles
r,    should be sent to add to its collection.
 
eD    In this manner, only those articles which are not duplicates and
&    which are desired are transferred.
 
n 
o 
o 
  
e 
i 
l 
a 
g 
i 
t 
o 
mI Kantor & Lapsley                                                [Page 4]
  
 
  
tI RFC 977                                                    February 1986
a Network News Transfer Protocol
  
  
t 2.  The NNTP Specification
  
  2.1.  Overview
  
 G    The news server specified by this document uses a stream connection
 G    (such as TCP) and SMTP-like commands and responses.  It is designed
.G    to accept connections from hosts, and to provide a simple interface
h    to the news database.
  
dB    This server is only an interface between programs and the news
H    databases. It does not perform any user interaction or presentation-
G    level functions. These "user-friendly" functions are better left to
cA    the client programs, which have a better understanding of the
i,    environment in which they are operating.
 
eB    When used via Internet TCP, the contact port assigned for this
    service is 119.
e 
g 2.2.  Character Codes
 
nB    Commands and replies are composed of characters from the ASCII
E    character set.  When the transport service provides an 8-bit byte
fE    (octet) transmission channel, each 7-bit character is transmitted
sH    right justified in an octet with the high order bit cleared to zero.
 
o 2.3.  Commands
  
 B    Commands consist of a command word, which in some cases may be
H    followed by a parameter.  Commands with parameters must separate the
H    parameters from each other and from the command by one or more space
H    or tab characters.  Command lines must be complete with all required
:    parameters, and may not contain more than one command.
 
dF    Commands and command parameters are not case sensitive. That is, a
C    command or parameter word may be upper case, lower case, or any
x$    mixture of upper and lower case.
 
eF    Each command line must be terminated by a CR-LF (Carriage Return -
    Line Feed) pair.
 
sI    Command lines shall not exceed 512 characters in length, counting all
wA    characters including spaces, separators, punctuation, and the
 I    trailing CR-LF (thus there are 510 characters maximum allowed for the
rH    command and its parameters).  There is no provision for continuation
    command lines.
 
e 
  
c 
rI Kantor & Lapsley                                                [Page 5]
y 
 
  
lI RFC 977                                                    February 1986
g Network News Transfer Protocol
l 
  
  2.4.  Responses
 
a3    Responses are of two kinds, textual and status.
i 
o 2.4.1.  Text Responses
  
vH    Text is sent only after a numeric status response line has been sent
F    that indicates that text will follow.  Text is sent as a series of
H    successive lines of textual matter, each terminated with CR-LF pair.
F    A single line containing only a period (.) is sent to indicate the
G    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).
 
sE    If the text contained a period as the first character of the text
 G    line in the original, that first period is doubled.  Therefore, the
dF    client must examine the first character of each line received, and
H    for those beginning with a period, determine either that this is the
I    end of the text or whether to collapse the doubled period to a single
T    one.
 
cH    The intention is that text messages will usually be displayed on the
H    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
f 
tI    These are status reports from the server and indicate the response to
T.    the last command received from the client.
 
tD    Status response lines begin with a 3 digit numeric code which is
F    sufficient to distinguish all responses.  Some of these may herald
(    the subsequent transmission of text.
 
oB    The first digit of the response broadly indicates the success,
1    failure, or progress of the previous command.
e 
f        1xx - Informative message
       2xx - Command ok
n4       3xx - Command ok so far, send the rest of it.
?       4xx - Command was correct, but couldn't be performed for
F             some reason.
h>       5xx - Command unimplemented, or incorrect, or a serious
$             program error occurred.
 
  
v 
  
  
g 
bI Kantor & Lapsley                                                [Page 6]
t 
 
  
rI RFC 977                                                    February 1986
c Network News Transfer Protocol
  
a 
cH    The next digit in the code indicates the function response category.
 
r:       x0x - Connection, setup, and miscellaneous messages
        x1x - Newsgroup selection
       x2x - Article selection
#       x3x - Distribution functions
o       x4x - Posting
<       x8x - Nonstandard (private implementation) extensions
       x9x - Debugging output
  
FF    The exact response codes that should be expected from each command
H    are detailed in the description of that command.  In addition, below
I    is listed a general set of response codes that may be received at any
 	    time.
s 
eC    Certain status responses contain parameters such as numbers and
gC    names. The number and type of such parameters is fixed for each
 =    response code to simplify interpretation of the response.
o 
eI    Parameters are separated from the numeric response code and from each
hH    other by a single space. All numeric parameters are decimal, and may
H    have leading zeros. All string parameters begin after the separating
E    space, and end before the following separating space or the CR-LF
sG    pair at the end of the line. (String parameters may not, therefore,

E    contain spaces.) All text, if any, in the response which is not a
 H    parameter of the response must follow and be separated from the last
H    parameter by a space.  Also, note that the text following a response
C    number may vary in different implementations of the server. The
pF    3-digit numeric code should be used to determine what response was
	    sent.
  
 E    Response codes not specified in this standard may be used for any
nG    installation-specific additional commands also not specified. These
 F    should be chosen to fit the pattern of x8x specified above.  (Note
I    that debugging is provided for explicitly in the x9x response codes.)
 B    The use of unspecified response codes for standard commands is
    prohibited.
s 
tF    We have provided a response pattern x9x for debugging.  Since much
G    debugging output may be classed as "informative messages", we would
dG    expect, therefore, that responses 190 through 199 would be used for
p?    various debugging outputs.  There is no requirement in this
sH    specification for debugging output, but if such is provided over the
G    connected stream, it must use these response codes.  If appropriate
iA    to a specific implementation, other x9x codes may be used for
hF    debugging.  (An example might be to use e.g., 290 to acknowledge a
    remote debugging request.)
 
r 
 I Kantor & Lapsley                                                [Page 7]
b 
 
  
tI RFC 977                                                    February 1986
  Network News Transfer Protocol
n 
u 
) 2.4.3.  General Responses
 
 I    The following is a list of general response codes that may be sent by
cH    the NNTP server.  These are not specific to any one command, but may
I    be returned as the result of a connection, a failure, or some unusual
t    condition.
 
 G    In general, 1xx codes may be ignored or displayed as desired;  code
eA    200 or 201 is sent upon initial connection to the NNTP server
sE    depending upon posting permission; code 400 will be sent when the
rH    NNTP server discontinues service (by operator request, for example);
F    and 5xx codes indicate that the command could not be performed for
    some unusual reason.
 
h       100 help text
       190
         through
       199 debug output
s 
d)       200 server ready - posting allowed
 ,       201 server ready - no posting allowed
 
        400 service discontinued
  
 !       500 command not recognized
        501 command syntax error
 2       502 access restriction or permission denied
0       503 program fault - command not performed
 
 ! 3.  Command and Response Details
w 
eI    On the following pages are descriptions of each command recognized by
)E    the NNTP server and the responses which will be returned by those
c
    commands.
  
tE    Each command is shown in upper case for clarity, although case is
 F    ignored in the interpretation of commands by the NNTP server.  Any
E    parameters are shown in lower case.  A parameter shown in [square
 A    brackets] is optional.  For example, [GMT] indicates that the
o(    triglyph GMT may present or omitted.
 
eF    Every command described in this section must be implemented by all
    NNTP servers.
a 
t 
e 
C 
t 
c 
aI Kantor & Lapsley                                                [Page 8]

 
 
  
mI RFC 977                                                    February 1986
s Network News Transfer Protocol
r 
d 
aD    There is no prohibition against additional commands being added;
F    however, it is recommended that any such unspecified command begin
F    with the letter "X" to avoid conflict with later revisions of this
    specification.
 
oC    Implementors are reminded that such additional commands may not
r?    redefine specified status response codes.  Using additional
cC    unspecified responses for standard commands is also prohibited.
s 
e1 3.1.  The ARTICLE, BODY, HEAD, and STAT commands
y 
tE    There are two forms to the ARTICLE command (and the related BODY,
sI    HEAD, and STAT commands), each using a different method of specifying
pB    which article is to be retrieved.  When the ARTICLE command is
G    followed by a message-id in angle brackets ("<" and ">"), the first
 I    form of the command is used; when a numeric parameter or no parameter
e,    is supplied, the second form is invoked.
 
dA    The text of the article is returned as a textual response, as
t'    described earlier in this document.
w 
fC    The HEAD and BODY commands are identical to the ARTICLE command
cF    except that they respectively return only the header lines or text
    body of the article.
 
 E    The STAT command is similar to the ARTICLE command except that no
 G    text is returned.  When selecting by message number within a group,
 F    the STAT command serves to set the current article pointer without
H    sending text. The returned acknowledgement response will contain the
F    message-id, which may be of some value.  Using the STAT command to
D    select by message-id is valid but of questionable value, since a
I    selection by message-id does NOT alter the "current article pointer".
n 
n* 3.1.1.  ARTICLE (selection by message-id)
 
d    ARTICLE <message-id>
 
rA    Display the header, a blank line, then the body (text) of the
aE    specified article.  Message-id is the message id of an article as
oF    shown in that article's header.  It is anticipated that the client
B    will obtain the message-id from a list provided by the NEWNEWS
F    command, from references contained within another article, or from
C    the message-id provided in the response to some other commands.
  
tH    Please note that the internally-maintained "current article pointer"
B    is NOT ALTERED by this command. This is both to facilitate the
E    presentation of articles that may be referenced within an article
  
  
 I Kantor & Lapsley                                                [Page 9]
s 
 
f 
tI RFC 977                                                    February 1986
T Network News Transfer Protocol
o 
h 
lG    being read, and because of the semantic difficulties of determining
iH    the proper sequence and membership of an article which may have been
&    posted to more than one newsgroup.
 
t& 3.1.2.  ARTICLE (selection by number)
 
b    ARTICLE [nnn]
e 
cB    Displays the header, a blank line, then the body (text) of the
D    current or specified article.  The optional parameter nnn is the
 
nH    numeric id of an article in the current newsgroup and must be chosen
H    from the range of articles provided when the newsgroup was selected.
5    If it is omitted, the current article is assumed.
  
rF    The internally-maintained "current article pointer" is set by this
3    command if a valid article number is specified.

 
 C    [the following applies to both forms of the article command.] A
uH    response indicating the current article number, a message-id string,
0    and that text is to follow will be returned.
 
 H    The message-id string returned is an identification string contained
I    within angle brackets ("<" and ">"), which is derived from the header
uC    of the article itself.  The Message-ID header line (required by
aH    RFC850) from the article must be used to supply this information. If
D    the message-id header line is missing from the article, a single
B    digit "0" (zero) should be supplied within the angle brackets.
 
 E    Since the message-id field is unique with each article, it may be
 I    used by a news reading program to skip duplicate displays of articles
mH    that have been posted more than once, or to more than one newsgroup.
 
h 3.1.3.  Responses
 
 6    220 n <a> article retrieved - head and body follow
2            (n = article number, <a> = message-id)
.    221 n <a> article retrieved - head follows
.    222 n <a> article retrieved - body follows
9    223 n <a> article retrieved - request text separately
r&    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
n 
a 
. 
l 
e 
 I Kantor & Lapsley                                               [Page 10]
  
 
a 
bI RFC 977                                                    February 1986
e Network News Transfer Protocol
e 
a 
a 3.2.  The GROUP command
 
n 3.2.1.  GROUP
 
e
    GROUP ggg
n 
rA    The required parameter ggg is the name of the newsgroup to be
 B    selected (e.g. "net.news").  A list of valid newsgroups may be
#    obtained from the LIST command.
t 
aH    The successful selection response will return the article numbers of
D    the first and last articles in the group, and an estimate of the
F    number of articles on file in the group.  It is not necessary that
F    the estimate be correct, although that is helpful; it must only be
I    equal to or larger than the actual number of articles on file.  (Some
oG    implementations will actually count the number of articles on file.
eF    Others will just subtract first article number from last to get an
    estimate.)
 
T@    When a valid group is selected by means of this command, the
G    internally maintained "current article pointer" is set to the first
e@    article in the group.  If an invalid group is specified, the
G    previously selected group and article remain selected.  If an empty
gA    newsgroup is selected, the "current article pointer" is in an
s/    indeterminate state and should not be used.
  
 G    Note that the name of the newsgroup is not case-dependent.  It must
 D    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
7            (n = estimated number of articles in group,
 2            f = first article number in the group,
1            l = last article number in the group,
i#            s = name of the group.)
c    411 no such news group
 
1 
c 
s 
y 
  
o 
  
d 
l 
d 
 I Kantor & Lapsley                                               [Page 11]
  
 
s 
 I RFC 977                                                    February 1986
T Network News Transfer Protocol
  
r 
r 3.3.  The HELP command
  
a
 3.3.1.  HELP
d 
t    HELP
 
mD    Provides a short summary of commands that are understood by this
F    implementation of the server. The help text will be presented as a
H    textual response, terminated by a single period on a line by itself.
 
o    3.3.2.  Responses
  
0    100 help text follows
  
  3.4.  The IHAVE command
 
d 3.4.1.  IHAVE
 
n    IHAVE <messageid>
  
 G    The IHAVE command informs the server that the client has an article
nB    whose id is <messageid>.  If the server desires a copy of that
I    article, it will return a response instructing the client to send the
eE    entire article.  If the server does not want the article (if, for
mH    example, the server already has a copy of it), a response indicating
4    that the article is not wanted will be returned.
 
bG    If transmission of the article is requested, the client should send
e@    the entire article, including header and body, in the manner
D    specified for text transmission from the server. A response code
H    indicating success or failure of the transferral of the article will
    be returned.
 
tF    This function differs from the POST command in that it is intended
B    for use in transferring already-posted articles between hosts.
>    Normally it will not be used when the client is a personal
F    newsreading program.  In particular, this function will invoke the
G    server's news posting program with the appropriate settings (flags,
fC    options, etc) to indicate that the forthcoming article is being
e     forwarded from another host.
 
nH    The server may, however, elect not to post or forward the article if
I    after further examination of the article it deems it inappropriate to
sH    do so.  The 436 or 437 error codes may be returned as appropriate to
    the situation.
 
,H    Reasons for such subsequent rejection of an article may include such
 
t 
rI Kantor & Lapsley                                               [Page 12]
o 
 
f 
gI RFC 977                                                    February 1986
f Network News Transfer Protocol
b 
k 
 E    problems as inappropriate newsgroups or distributions, disk space
rG    limitations, article lengths, garbled headers, and the like.  These
dA    are typically restrictions enforced by the server host's news
e8    software and not necessarily the NNTP server itself.
 
H 3.4.2.  Responses
 
r    235 article transferred ok
A    335 send article to be transferred.  End with <CR-LF>.<CR-LF>
 +    435 article not wanted - do not send it
e)    436 transfer failed - try again later
m+    437 article rejected - do not try again
h 
s    An implementation note:
t 
 E    Because some host news posting software may not be able to decide
e?    immediately that an article is inappropriate for posting or
eG    forwarding, it is acceptable to acknowledge the successful transfer
 @    of the article and to later silently discard it.  Thus it is
F    permitted to return the 235 acknowledgement code and later discard
G    the received article.  This is not a fully satisfactory solution to
 H    the problem.  Perhaps some implementations will wish to send mail to
8    the author of the article in certain of these cases.
 
  3.5.  The LAST command
r 
l
 3.5.1.  LAST
n 
     LAST
 
sE    The internally maintained "current article pointer" is set to the
eH    previous article in the current newsgroup.  If already positioned at
H    the first article of the newsgroup, an error message is returned and
)    the current article remains selected.
P 
sF    The internally-maintained "current article pointer" is set by this
    command.
 
iF    A response indicating the current article number, and a message-id
A    string will be returned.  No text is sent in response to this
y    command.
 
  3.5.2.  Responses
 
 7    223 n a article retrieved - request text separately
 7            (n = article number, a = unique article id)
e 
T 
s 
 I Kantor & Lapsley                                               [Page 13]
  
 
r 
iI RFC 977                                                    February 1986
e Network News Transfer Protocol
w 
o 

    412 no newsgroup selected
n,    420 no current article has been selected
)    422 no previous article in this group
b 
  3.6.  The LIST command
t 
 
 3.6.1.  LIST
l 
     LIST
 
pH    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

 
 G    where <group> is the name of the newsgroup, <last> is the number of
lF    the last known article currently in that newsgroup, <first> is the
F    number of the first article currently in the newsgroup, and <p> is
E    either 'y' or 'n' indicating whether posting to this newsgroup is
e&    allowed ('y') or prohibited ('n').
 
 H    The <first> and <last> fields will always be numeric.  They may have
B    leading zeros.  If the <last> field evaluates to less than the
A    <first> field, there are no articles currently on file in the
h    newsgroup.
 
TI    Note that posting may still be prohibited to a client even though the
bD    LIST command indicates that posting is permitted to a particular
@    newsgroup. See the POST command for an explanation of client
E    prohibitions.  The posting flag exists for each newsgroup because
iI    some newsgroups are moderated or are digests, and therefore cannot be
gC    posted to; that is, articles posted to them must be mailed to a
dH    moderator who will post them for the submitter.  This is independent
E    of the posting permission granted to a client by the NNTP server.
( 
 H    Please note that an empty list (i.e., the text body returned by this
H    command consists only of the terminating period) is a possible valid
I    response, and indicates that there are currently no valid newsgroups.
l 
e 3.6.2.  Responses
 
r"    215 list of newsgroups follows
 
h 
t 
e 
m 
  
t 
 I Kantor & Lapsley                                               [Page 14]
y 
 
  
 I RFC 977                                                    February 1986
  Network News Transfer Protocol
  
  
  3.7.  The NEWGROUPS command
 
a 3.7.1.  NEWGROUPS
 
a/    NEWGROUPS date time [GMT] [<distributions>]
e 
 H    A list of newsgroups created since <date and time> will be listed in
(    the same format as the LIST command.
 
 F    The date is sent as 6 digits in the format YYMMDD, where YY is the
H    last two digits of the year, MM is the two digits of the month (with
G    leading zero, if appropriate), and DD is the day of the month (with
 E    leading zero, if appropriate).  The closest century is assumed as
 G    part of the year (i.e., 86 specifies 1986, 30 specifies 2030, 99 is
     1999, 00 is 2000).
 
eG    Time must also be specified.  It must be as 6 digits HHMMSS with HH
uF    being hours on the 24-hour clock, MM minutes 00-59, and SS seconds
I    00-59.  The time is assumed to be in the server's timezone unless the
 G    token "GMT" appears, in which case both time and date are evaluated
n    at the 0 meridian.
 
nD    The optional parameter "distributions" is a list of distribution
G    groups, enclosed in angle brackets.  If specified, the distribution
eC    portion of a new newsgroup (e.g, 'net' in 'net.wombat') will be
eE    examined for a match with the distribution categories listed, and
 G    only those new newsgroups which match will be listed.  If more than
tE    one distribution group is to be listed, they must be separated by

%    commas within the angle brackets.
e 
nH    Please note that an empty list (i.e., the text body returned by this
H    command consists only of the terminating period) is a possible valid
G    response, and indicates that there are currently no new newsgroups.
m 
f 3.7.2.  Responses
 
n&    231 list of new newsgroups follows
 
  
  
  
  
  
  
t 
& 
p 
y 
  
 I Kantor & Lapsley                                               [Page 15]
  
 
  
 I RFC 977                                                    February 1986
r Network News Transfer Protocol
c 
a 
  3.8.  The NEWNEWS command
 
L 3.8.1.  NEWNEWS
 
 7    NEWNEWS newsgroups date time [GMT] [<distribution>]
  
pI    A list of message-ids of articles posted or received to the specified
lI    newsgroup since "date" will be listed. The format of the listing will
2I    be one message-id per line, as though text were being sent.  A single

I    line consisting solely of one period followed by CR-LF will terminate
i
    the list.
e 
hB    Date and time are in the same format as the NEWGROUPS command.
 
vG    A newsgroup name containing a "*" (an asterisk) may be specified to
tG    broaden the article search to some or all newsgroups.  The asterisk
wA    will be extended to match any part of a newsgroup name (e.g.,
pG    net.micro* will match net.micro.wombat, net.micro.apple, etc). Thus
bF    if only an asterisk is given as the newsgroup name, all newsgroups
"    will be searched for new news.
 
l=    (Please note that the asterisk "*" expansion is a general
tE    replacement; in particular, the specification of e.g., net.*.unix
sI    should be correctly expanded to embrace names such as net.wombat.unix
     and net.whocares.unix.)
  
 F    Conversely, if no asterisk appears in a given newsgroup name, only
H    the specified newsgroup will be searched for new articles. Newsgroup
H    names must be chosen from those returned in the listing of available
H    groups.  Multiple newsgroup names (including a "*") may be specified
G    in this command, separated by a comma.  No comma shall appear after
rH    the last newsgroup in the list.  [Implementors are cautioned to keep
4    the 512 character command length limit in mind.]
 
 G    The exclamation point ("!") may be used to negate a match. This can
 D    be used to selectively omit certain newsgroups from an otherwise
<    larger list.  For example, a newsgroups specification of
F    "net.*,mod.*,!mod.map.*" would specify that all net.<anything> and
I    all mod.<anything> EXCEPT mod.map.<anything> newsgroup names would be
 E    matched.  If used, the exclamation point must appear as the first
 5    character of the given newsgroup name or pattern.
o 
aD    The optional parameter "distributions" is a list of distribution
G    groups, enclosed in angle brackets.  If specified, the distribution
cG    portion of an article's newsgroup (e.g, 'net' in 'net.wombat') will
lH    be examined for a match with the distribution categories listed, and
F    only those articles which have at least one newsgroup belonging to
 
L 
 I Kantor & Lapsley                                               [Page 16]
y 
 
l 
rI RFC 977                                                    February 1986
n Network News Transfer Protocol
n 
  
t?    the list of distributions will be listed.  If more than one
aC    distribution group is to be supplied, they must be separated by
a%    commas within the angle brackets.
f 
 G    The use of the IHAVE, NEWNEWS, and NEWGROUPS commands to distribute
r:    news is discussed in an earlier part of this document.
 

H    Please note that an empty list (i.e., the text body returned by this
H    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
 
 2    230 list of new articles by message-id follows
 
n 3.9.  The NEXT command
o 
e
 3.9.1.  NEXT
e 
     NEXT
 
rF    The internally maintained "current article pointer" is advanced to
C    the next article in the current newsgroup.  If no more articles
cE    remain in the current group, an error message is returned and the
u%    current article remains selected.
  
cF    The internally-maintained "current article pointer" is set by this
    command.
 
sH    A response indicating the current article number, and the message-id
A    string will be returned.  No text is sent in response to this
e    command.
 
y 3.9.2.  Responses
 
i7    223 n a article retrieved - request text separately
&7            (n = article number, a = unique article id)
a    412 no newsgroup selected
 ,    420 no current article has been selected
%    421 no next article in this group
e 
r 
c 
w 
o 

 
  
2 
  
sI Kantor & Lapsley                                               [Page 17]
r 
 
a 
cI RFC 977                                                    February 1986
  Network News Transfer Protocol
v 
d 
w 3.10.  The POST command
 
a 3.10.1.  POST
 
w    POST
 
tI    If posting is allowed, response code 340 is returned to indicate that

H    the article to be posted should be sent. Response code 440 indicates
F    that posting is prohibited for some installation-dependent reason.
 

C    If posting is permitted, the article should be presented in the
iF    format specified by RFC850, and should include all required header
H    lines. After the article's header and body have been completely sent
I    by the client to the server, a further response code will be returned
l:    to indicate success or failure of the posting attempt.
 
 D    The text forming the header and body of the message to be posted
H    should be sent by the client using the conventions for text received
H    from the news server:  A single period (".") on a line indicates the
F    end of the text, with lines starting with a period in the original
8    text having that period doubled during transmission.
 
sH    No attempt shall be made by the server to filter characters, fold or
F    limit lines, or otherwise process incoming text.  It is our intent
F    that the server just pass the incoming message to be posted to the
G    server installation's news posting software, which is separate from
 5    this specification.  See RFC850 for more details.
r 
rG    Since most installations will want the client news program to allow
sG    the user to prepare his message using some sort of text editor, and
dH    transmit it to the server for posting only after it is composed, the
I    client program should take note of the herald message that greeted it
 E    when the connection was first established. This message indicates
 F    whether postings from that client are permitted or not, and can be
H    used to caution the user that his access is read-only if that is the
E    case. This will prevent the user from wasting a good deal of time
nG    composing a message only to find posting of the message was denied.
oG    The method and determination of which clients and hosts may post is
rD    installation dependent and is not covered by this specification.
 
w 3.10.2.  Responses
  
t    240 article posted ok
r;    340 send article to be posted. End with <CR-LF>.<CR-LF>
z    440 posting not allowed
o    441 posting failed
 
  
  
rI Kantor & Lapsley                                               [Page 18]
, 
 
2 
)I RFC 977                                                    February 1986
  Network News Transfer Protocol
u 
l 
,H    (for reference, one of the following codes will be sent upon initial
F    connection; the client program should determine whether posting is
G    generally permitted from these:) 200 server ready - posting allowed
e)    201 server ready - no posting allowed
s 
f 3.11.  The QUIT command
 
c 3.11.1.  QUIT
 
k    QUIT
 
iH    The server process acknowledges the QUIT command and then closes the
H    connection to the client.  This is the preferred method for a client
G    to indicate that it has finished all its transactions with the NNTP
e    server.
h 
tH    If a client simply disconnects (or the connection times out, or some
H    other fault occurs), the server should gracefully cease its attempts
    to service the client.
 
e 3.11.2.  Responses
d 
n%    205 closing connection - goodbye!
s 
p 3.12.  The SLAVE command
, 
d 3.12.1.  SLAVE
h 
 	    SLAVE
l 
oE    Indicates to the server that this client connection is to a slave
g    server, rather than a user.
  
 H    This command is intended for use in separating connections to single
H    users from those to subsidiary ("slave") servers.  It may be used to
E    indicate that priority should therefore be given to requests from
lF    this client, as it is presumably serving more than one person.  It
C    might also be used to determine which connections to close when
mG    system load levels are exceeded, perhaps giving preference to slave
p?    servers.  The actual use this command is put to is entirely
 H    implementation dependent, and may vary from one host to another.  In
B    NNTP servers which do not give priority to slave servers, this
<    command must nonetheless be recognized and acknowledged.
 
a 3.12.2.  Responses
m 
d    202 slave status noted
 
t 
iI Kantor & Lapsley                                               [Page 19]
  
 
  
aI RFC 977                                                    February 1986
n Network News Transfer Protocol
c 
  
l 4.  Sample Conversations
t 
cF    These are samples of the conversations that might be expected with
H    the news server in hypothetical sessions.  The notation C: indicates
I    commands sent to the news server from the client program; S: indicate
r5    responses received from the server by the client.
o 
 , 4.1.  Example 1 - relative access with NEXT
 
t%    S:      (listens at TCP port 119)
x 
 1    C:      (requests connection on TCP port 119)
v8    S:      200 wombatvax news server ready - posting ok
 
s.    (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:      .
t 
l     (client selects a newsgroup)
"    C:      GROUP net.unix-wizards
?    S:      211 104 10011 10125 net.unix-wizards group selected
yA            (there are 104 articles on file, from 10011 to 10125)
m 
c'    (client selects an article to read)
l    C:      STAT 10110
I    S:      223 10110 <23445@sdcsvax.ARPA> article retrieved - statistics
 ;            only (article 10110 selected, its message-id is
d!            <23445@sdcsvax.ARPA>)
l 
e     (client examines the header)
    C:      HEAD
C    S:      221 10110 <23445@sdcsvax.ARPA> article retrieved - head
a5            follows (text of the header appears here)
 
    S:      .
s 
b6    (client wants to see the text body of the article)
    C:      BODY
C    S:      222 10110 <23445@sdcsvax.ARPA> article retrieved - body
a$            follows (body text here)

    S:      .
i 
i*    (client selects next article in group)
 
l 
wI Kantor & Lapsley                                               [Page 20]
  
 
  
 I RFC 977                                                    February 1986
  Network News Transfer Protocol
  
  
b    C:      NEXT
I    S:      223 10113 <21495@nudebch.uucp> article retrieved - statistics
l2            only (article 10113 was next in group)
 
     (client finishes session)
a    C:      QUIT
    S:      205 goodbye.
 
f7 4.2.  Example 2 - absolute article access with ARTICLE
m 
s%    S:      (listens at TCP port 119)
i 
n1    C:      (requests connection on TCP port 119)
eB    S:      201 UCB-VAX netnews server ready -- no posting allowed
 
c    C:      GROUP msgs
7    S:      211 103 402 504 msgs Your new group is msgs
d5            (there are 103 articles, from 402 to 504)
. 
e    C:      ARTICLE 401
 1    S:      423 No such article in this newsgroup
h 
E    C:      ARTICLE 402
 F    S:      220 402 <4105@ucbvax.ARPA> Article retrieved, text follows
,    S:      (article header and body follow)

    S:      .
n 
g    C:      HEAD 403
G    S:      221 403 <3108@mcvax.UUCP> Article retrieved, header follows
t$    S:      (article header follows)

    S:      .
T 
i    C:      QUIT
A    S:      205 UCB-VAX news server closing connection.  Goodbye.
A 
s$ 4.3.  Example 3 - NEWGROUPS command
 
e%    S:      (listens at TCP port 119)
b 
e1    C:      (requests connection on TCP port 119)
cB    S:      200 Imaginary Institute News Server ready (posting ok)
 
q8    (client asks for new newsgroups since April 3, 1985)
#    C:      NEWGROUPS 850403 020000
s 
u=    S:      231 New newsgroups since 03/04/85 02:00:00 follow
4 
n 
e 
aI Kantor & Lapsley                                               [Page 21]
y 
 
  
 I RFC 977                                                    February 1986
  Network News Transfer Protocol
  
  
     S:      net.music.gdead
s    S:      net.games.sources
.
    S:      .
o 
n!    C:      GROUP net.music.gdead

8    S:      211 0 1 1 net.music.gdead Newsgroup selected
9            (there are no articles in that newsgroup, and
bA            the first and last article numbers should be ignored)
  
     C:      QUIT
F    S:      205 Imaginary Institute news server ceasing service.  Bye!
 
r) 4.4.  Example 4 - posting a news article
C 
,%    S:      (listens at TCP port 119)

 
 1    C:      (requests connection on TCP port 119)
e=    S:      200 BANZAIVAX news server ready, posting allowed.
e 
n    C:      POST
C    S:      340 Continue posting; Period on a line by itself to end
 5    C:      (transmits news article in RFC850 format)
a
    C:      .

,    S:      240 Article posted successfully.
 
n    C:      QUIT
7    S:      205 BANZAIVAX closing connection.  Goodbye.
n 
l7 4.5.  Example 5 - interruption due to operator request
n 
i%    S:      (listens at TCP port 119)
a 
g1    C:      (requests connection on TCP port 119)
NA    S:      201 genericvax news server ready, no posting allowed.

 
 :            (assume normal conversation for some time, and
/            that a newsgroup has been selected)
n 
e    C:      NEXT
H    S:      223 1013 <5734@mcvax.UUCP> Article retrieved; text separate.
 
r    C:      HEAD
G    C:      221 1013 <5734@mcvax.UUCP> Article retrieved; head follows.
n 
i:    S:      (sends head of article, but halfway through is
>            interrupted by an operator request.  The following
6            then occurs, without client intervention.)
 
d 
hI Kantor & Lapsley                                               [Page 22]
t 
 
w 
 I RFC 977                                                    February 1986
p Network News Transfer Protocol
i 
d 
 1    S:      (ends current line with a CR-LF pair)
h
    S:      .
a8    S:      400 Connection closed by operator.  Goodbye.
    S:      (closes connection)
e 
 C 4.6.  Example 6 - Using the news server to distribute news between
.       systems.
  
 %    S:      (listens at TCP port 119)
s 
y1    C:      (requests connection on TCP port 119)
v5    S:      201 Foobar NNTP server ready (no posting)
  
 =    (client asks for new newsgroups since 2 am, May 15, 1985)
n#    C:      NEWGROUPS 850515 020000
i2    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
w4    S:      230 New news since 850515 020000 follows
    S:      <1772@foo.UUCP>
     S:      <87623@baz.UUCP>
    S:      <17872@GOLD.CSNET>

    S:      .
e 
e-    (client asks for article <1772@foo.UUCP>)
h#    C:      ARTICLE <1772@foo.UUCP>
w6    S:      220 <1772@foo.UUCP> All of article follows
"    S:      (sends entire message)

    S:      .
Q 

-    (client asks for article <87623@baz.UUCP>
I$    C:      ARTICLE <87623@baz.UUCP>
7    S:      220 <87623@baz.UUCP> All of article follows
a"    S:      (sends entire message)

    S:      .
t 
r/    (client asks for article <17872@GOLD.CSNET>
I&    C:      ARTICLE <17872@GOLD.CSNET>
9    S:      220 <17872@GOLD.CSNET> All of article follows
e"    S:      (sends entire message)

    S:      .
e 
c 
h 
l 
tI Kantor & Lapsley                                               [Page 23]
p 
 
  
eI RFC 977                                                    February 1986
  Network News Transfer Protocol
c 
n 
 7    (client offers an article it has received recently)
i$    C:      IHAVE <4105@ucbvax.ARPA>
6    S:      435 Already seen that one, where you been?
 
i#    (client offers another article)
d$    C:      IHAVE <4106@ucbvax.ARPA>
0    S:      335 News to me!  <CRLF.CRLF> to end.
    C:      (sends article)
v
    C:      .
n:    S:      235 Article transferred successfully.  Thanks.
 
t    (or)
 
      S:      436 Transfer failed.
 
e,    (client is all through with the session)
    C:      QUIT
5    S:      205 Foobar NNTP server bids you farewell.
e 
t) 4.7.  Summary of commands and responses.
o 
oG    The following are the commands recognized and responses returned by
t    the NNTP server.
 
e 4.7.1.  Commands
e 
n    ARTICLE
d    BODY
	    GROUP
o    HEAD
    HELP
	    IHAVE
     LAST
    LIST

    NEWGROUPS
     NEWNEWS
     NEXT
    POST
    QUIT
	    SLAVE
     STAT
 
F 4.7.2.  Responses
 
     100 help text follows
     199 debug output
 
w 
  
sI Kantor & Lapsley                                               [Page 24]
s 
 
o 
hI RFC 977                                                    February 1986
t Network News Transfer Protocol
n 
a 

&    200 server ready - posting allowed
)    201 server ready - no posting allowed
s    202 slave status noted
%    205 closing connection - goodbye!
     211 n f l s group selected
"    215 list of newsgroups follows
H    220 n <a> article retrieved - head and body follow 221 n <a> article
    retrieved - head follows
.    222 n <a> article retrieved - body follows
I    223 n <a> article retrieved - request text separately 230 list of new
o"    articles by message-id follows
&    231 list of new newsgroups follows
    235 article transferred ok
    240 article posted ok
  
 A    335 send article to be transferred.  End with <CR-LF>.<CR-LF>
a;    340 send article to be posted. End with <CR-LF>.<CR-LF>
2 
1    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
1)    422 no previous article in this group
A,    423 no such article number in this group
    430 no such article found
i+    435 article not wanted - do not send it
.)    436 transfer failed - try again later
r,    437 article rejected - do not try again.
    440 posting not allowed
r    441 posting failed
 
f    500 command not recognized
    501 command syntax error
/    502 access restriction or permission denied
t-    503 program fault - command not performed
< 
40 4.8.  A Brief Word about the USENET News System
 
 G    In the UNIX world, which traditionally has been linked by 1200 baud
rI    dial-up telephone lines, the USENET News system has evolved to handle
 I    central storage, indexing, retrieval, and distribution of news.  With
 F    the exception of its underlying transport mechanism (UUCP), USENET
H    News is an efficient means of providing news and bulletin service to
C    subscribers on UNIX and other hosts worldwide.  The USENET News
n 
o 

 
  
 I Kantor & Lapsley                                               [Page 25]
f 
 
  
mI RFC 977                                                    February 1986
T Network News Transfer Protocol
e 
s 
cG    system is discussed in detail in RFC 850.  It runs on most versions
 C    of UNIX and on many other operating systems, and is customarily
3    distributed without charge.
s 
dH    USENET uses a spooling area on the UNIX host to store news articles,
D    one per file. Each article consists of a series of heading text,
@    which contain the sender's identification and organizational
B    affiliation, timestamps, electronic mail reply paths, subject,
H    newsgroup (subject category), and the like.  A complete news article
I    is reproduced in its entirety below.  Please consult RFC 850 for more
d    details.
 
S?       Relay-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site
v       sdcsvax.UUCP
.F       Posting-Version: version B 2.10.1 6/24/83 SMI; site unitek.uucp
I       Path:sdcsvax!sdcrdcf!hplabs!qantel!ihnp4!alberta!ubc-vision!unitek
        !honman
*       From: honman@unitek.uucp (Man Wong)
#       Newsgroups: net.unix-wizards
o*       Subject: foreground -> background ?
$       Message-ID: <167@unitek.uucp>
#       Date: 25 Sep 85 23:51:52 GMT
3,       Date-Received: 29 Sep 85 09:54:48 GMT
2       Reply-To: honman@unitek.UUCP (Hon-Man Wong)
       Distribution: net.all
4       Organization: Unitek Technologies Corporation
       Lines: 12
 
eI       I have a process (C program) which generates a child and waits for
 F       it to return.  What I would like to do is to be able to run the
I       child process interactively for a while before kicking itself into
 F       the background so I can return to the parent process (while the
I       child process is RUNNING in the background).  Can it be done?  And
        if it can, how?
 
e2       Please reply by E-mail.  Thanks in advance.
 
        Hon-Man Wong
t 
e 
  
  
S 
  
( 
t 
  
T 
p 
 I Kantor & Lapsley                                               [Page 26]
2 
 
A 
XI RFC 977                                                    February 1986
0 Network News Transfer Protocol
n 
y 
s 5.  References
C 
 D    [1]  Crocker, D., "Standard for the Format of ARPA Internet Text
B         Messages", RFC-822, Department of Electrical Engineering,
.         University of Delaware, August, 1982.
 
 C    [2]  Horton, M., "Standard for Interchange of USENET Messages",
S-         RFC-850, USENET Project, June, 1983.
  
(C    [3]  Postel, J., "Transmission Control Protocol- DARPA Internet
sB         Program Protocol Specification", RFC-793, USC/Information
-         Sciences Institute, September, 1981.
a 
 >    [4]  Postel, J., "Simple Mail Transfer Protocol", RFC-821,
:         USC/Information Sciences Institute, August, 1982.
 
  6.  Acknowledgements
  
 D    The authors wish to express their heartfelt thanks to those many
H    people who contributed to this specification, and especially to Erik
I    Fair and Chuq von Rospach, without whose inspiration this whole thing
 "    would not have been necessary.
 
 
 7.  Notes
 
y1    <1> UNIX is a trademark of Bell Laboratories.
e 
] 
  
  
  
  
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  
  
  
  
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F 
u 
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6I Kantor & Lapsley                                               [Page 27]
  
