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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
                           Network News Transport Protocol
                           draft-ietf-nntpext-base-12.txt
          
          
          1. Status of this Document
          
            This document is an Internet-Draft and is in full conformance
            with Section 10 of RFC 2026. Internet-Drafts are working
            documents of the Internet Engineering Task Force (IETF), its
            areas, and its working groups.  Note that other groups may
            also distribute working documents as Internet-Drafts.
            Internet-Drafts are draft documents valid for a maximum of six
            months and may be updated, replaced, or made obsolete by other
            documents at any time.  It is inappropriate to use Internet-
            Drafts as reference material or to cite them other than as
            "work in progress."
          
            The list of current Internet-Drafts can be accesses at
            http://www.ietf.org/ietf/1id-abstracts.txt.
            The list of Internet-Draft shadow directories can be accessed
            at http://www.ietf.org/shadow.html.
            This section will be updated with the appropriate verbiage
            from RFC 2223 should this document has been found ready for
            publication as an RFC.
          
            This document is a product of the NNTP Working Group, chaired
            by Ned Freed and Stan Barber.
          
          2. Abstract
          
            The Network News Transport Protocol has been in use in the
            Internet for a decade and remains one of the most popular
            protocols (by volume) in use today. This document is a
            replacement for RFC 977 and officially updates the protocol
            specification. It clarifies some vagueness in RFC 977,
            includes some new base functionality and provides a specific
            mechanism to add standardized extensions to NNTP.
          
          3. Introduction
          
            This document specifies the Network News Transport Protocol
            (NNTP), which is used for the distribution, inquiry,
            retrieval, and posting of net news articles using a reliable
            stream-based mechanism. For news reading clients, NNTP enables
            retrieval of news articles that are stored in a central
          
          
          Barber                                              [Page 1]
          

          INTERNET DRAFT                                          S. Barber
          
          Expires: June 30, 2001                 Academ Consulting Services
          
                                                              November 2000
          
            database, giving subscribers the ability to select only those
            articles they wish to read.
          
            The netnews model provides for indexing, cross-referencing,
            and expiration of aged messages. For server-to-server
            interaction, NNTP is designed for efficient transmission of
            net news articles over a reliable full duplex communication
            method.
          
            Every attempt is made to insure that the protocol
            specification in this document is compatible with the version
            specified in RFC 977[1]. However, this version does not
            support the ill-defined SLAVE command and permits four digit
            years to be specified in the NEWNEWS and NEWGROUPS commands.
            It changes the default character set to UTF-8[2] instead of
            US-ASCII[3]. It also extends the newsgroup name matching
            capabilities already documented in RFC 977.
          
            Generally, new functionality is available using new keywords.
            Part of that new functionality involves a mechanism to
            discover what new functionality is available to clients from a
            server.
          
            This mechanism can also be used to add more functionality as
            needs merit such additions.
          
            The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
            NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
            "OPTIONAL" in this document are to be interpreted as described
            in RFC 2119[4].
          
            An implementation is not compliant if it fails to satisfy one
            or more of the MUST requirements for this protocol.  An
            implementation that satisfies all the MUST and all the SHOULD
            requirements for its protocols is said to be "unconditionally
            compliant"; one that satisfies all the MUST requirements but
            not all the SHOULD requirements for NNTP is said to be
            "conditionally compliant".
          
            For the remainder of this memo, the term "client host" refers
            to a host making use of the NNTP service, while the term
            "server host" refers to a host that offers the NNTP service.
          
            In addition, where examples of interactions between a client
            host and a server host are provided a "[C]" will be used to
            represent the client host and a "[S]" will be used to
            represent the server host.
          
          
          4. Basic Operation.
          
            Every NNTP session MUST involve the following in this order:
          
          
          Barber                                              [Page 2]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            CONNECTION
          
            GREETING
          
            DISCONNECTION
          
            Other steps may occur between the GREETING and DISCONNECTION
            step. They are:
          
            CAPABILITIES DISCOVERY
          
            NEWS EXCHANGE
          
            CONCLUSION
          
            NNTP operates over any reliable data stream 8-bit-wide
            channel. When running over TCP/IP, the official port for the
            NNTP service is 119. Initially, the server host starts the
            NNTP service by listening on a TCP port.  When a client host
            wishes to make use of the service, it MUST establish a TCP
            connection with the server host by connecting to that host on
            the same port on which the server is listening. This is the
            CONNECTION step.  When the connection is established, the NNTP
            server host MUST send a greeting. This is the GREETING step.
          
            The client host and server host SHOULD then exchange commands
            and responses (respectively) until the connection is closed or
            aborted. This final step is called the DISCONNECTION step.
          
            If there is a CONCLUSION step, it MUST immediately precede the
            DISCONNECTION step. There MUST be only one CONNECTION,
            CONCLUSION and DISCONNECTION step for each NNTP session. All
            other steps MAY be repeated as needed. For example, the
            GREETING step may be repeated if the client makes use of the
            MODE READER command (See Section 7.2 for more on the MODE
            READER command).
          
            The character set for all NNTP commands is UTF-8. Commands in
            the NNTP MUST consist of an US-ASCII case-insensitive keyword,
            which MAY be followed by one or more arguments.  An US-ASCII
            CRLF pair MUST terminate all commands. Multiple commands MUST
            NOT be on the same line. Keywords MUST consist of printable
            US-ASCII characters.  Unless otherwise noted elsewhere in this
            document, arguments SHOULD consist of printable US-ASCII
            characters. Keywords and arguments MUST be each separated by
            one or more US-ASCII SPACE or US-ASCII TAB characters.
          
            Keywords MUST be at least three US-ASCII characters and MUST
            NOT exceed 12 US-ASCII characters.  Command lines MUST NOT
            exceed 512 octets, which includes the terminating US-ASCII
            CRLF pair. Arguments MUST NOT exceed 497 octets.
          
            Each response MUST start with a three-digit response code that
            is sufficient to distinguish all responses. Certain valid
            responses are defined to be multi-line; for all others, the
            response is contained in a single line. All multi-line
          
          Barber                                              [Page 3]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            responses MUST adhere to the following format: After sending
            the first line of the response and an US-ASCII CRLF, any
            additional lines are sent, each terminated by an US-ASCII CRLF
            pair. When all lines of the response have been sent, a final
            line MUST be sent, consisting of a termination octet (US-ASCII
            decimal code 046, ".") and an US-ASCII CRLF pair.  If any line
            of the multi-line response begins with the termination octet,
            the line MUST be "byte-stuffed" by pre-pending the termination
            octet to that line of the response. Hence, a multi-line
            response is terminated with the five octets "CRLF.CRLF" (in
            US-ASCII).  When examining a multi-line response, the client
            MUST check to see if the line begins with the termination
            octet. If so and if octets other than US-ASCII CRLF follow,
            the first octet of the line (the termination octet) MUST be
            stripped away.  If so and if US-ASCII CRLF immediately follows
            the termination character, then the response from the NNTP
            server is ended and the line containing ".CRLF" (in US-ASCII)
            MUST NOT be considered part of the multi-line response. Where
            a response is multi-line, the description of the command will
            define the format of the response before "byte-stuffing" takes
            place.
          
            A NNTP server MAY have an inactivity autologout timer. Such a
            timer MUST be of at least three minutes duration.  The receipt
            of any command from the client during that interval SHOULD
            suffice to reset the autologout timer.  When the timer
            expires, the server should close the TCP connection without
            sending any response to the client.
          
          4.1  Response Codes
          
            Each response MUST begin with a three-digit status indicator.
            These are status reports from the server and indicate the
            response to the last command received from the client.
          
            The first digit of the response broadly indicates the success,
            failure, or progress of the previous command.
          
            1xx - Informative message
          
            2xx - Command ok
          
            3xx - Command ok so far, send the rest of it.
          
            4xx - Command was correct, but couldn't be performed for some
               reason.
          
            5xx - Command unimplemented, or incorrect, or a serious
               program error occurred.
          
            The next digit in the code indicates the function response
            category.
          
            x0x - Connection, setup, and miscellaneous messages
          
          Barber                                              [Page 4]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            x1x - Newsgroup selection
          
            x2x - Article selection
          
            x3x - Distribution functions
          
            x4x - Posting
          
            x8x - Reserved for authentication and authorization extensions
          
            x9x - Reserved for private use (non-standard extensions)
          
            Certain responses contain parameters such as numbers and names
            in addition to the status indicator. In those cases, the
            number and type of such parameters is fixed for each response
            code to simplify interpretation by the client (any extension
            MUST follow this principle as well). In all other cases, the
            client MUST only use the status indicator itself to determine
            the nature of the response. The exact response codes that can
            be returned in response to a given command are detailed in the
            description of the keyword that is the first part of the
            command.
          
            Parameters MUST be separated from the numeric status indicator
            and from each other by a single US-ASCII space. All numeric
            parameters MUST be in base 10 (decimal) format, and MAY have
            leading zeros. String parameters MUST contain at least one
            character and MUST NOT contain US-ASCII spaces, CR, LF, or
            tab). The server MAY add any text after the response code or
            last parameter as appropriate, and the client MUST NOT make
            decisions based on this text. Such text MUST be separated from
            the numeric status indicator or the last parameter by at least
            one US-ASCII space.
          
            A server MUST respond to an unrecognized, unimplemented, or
            invalid command with a negative response code as follows. An
            unrecognized command, or an optional command or extension that
            is not implemented by the server, MUST be given a 500
            response. A syntax error in a recognized command MUST be given
            a 501 response. A command that is valid but not permitted
            because of the current internal state of the server MUST be
            given a 4XX or 5XX response.
          
            Each recognized command MUST return 501 (as above) or one of
            the response codes specifically listed in its description or
            in an extension. A server MAY provide extensions to this
            specification, including new commands, new features of
            existing commands, and other ways of changing the internal
            state of the server. However, the server MUST NOT produce any
            other responses to a client that does not invoke any of the
            additional features. (Therefore a client that restricts itself
            to this specification will only receive the responses that are
            listed).
          
          
          Barber                                              [Page 5]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            If a client receives an unexpected response, it SHOULD use the
            first digit of the response to determine the result. For
            example, an unexpected 2xx should be taken as success and an
            unexpected 4xx or 5xx as failure.
          
            Response codes not specified in this standard MAY be used for
            any installation-specific additional commands also not
            specified. These SHOULD be chosen to fit the pattern of x9x
            specified above.
          
            Neither this document nor any extension registered with IANA
            (see section 12) will specify any response codes of the x9x
            pattern. (Implementers of extensions are accordingly cautioned
            not to use such responses for extensions that may subsequently
            be submitted for registration.)
          
          5. The WILDMAT format
          
          
            The WILDMAT format[5] described here is based on the version
            first developed by Rich Salz which was derived from the format
            used in the UNIX "find" command to articulate file names. It
            was developed to provide a uniform mechanism for matching
            patterns in the same manner that the UNIX shell matches
            filenames. Patterns are implicitly anchored at the beginning
            and end of each string when testing for a match.  There are
            five pattern-matching operations other than a strict one-to-
            one match between the pattern and the source to be checked for
            a match. The first is an asterisk (*) to match any sequence of
            zero or more UTF-8 characters. The second is a question mark
            (?) to match any single UTF-8 character. The third specifies a
            specific set of characters. The set is specified as a list of
            characters, or as a range of characters where the beginning
            and end of the range are separated by a minus (or dash)
            character, or as any combination of lists and ranges. The dash
            can also be included in the set as a character it if is the
            beginning or end of the set. This set is enclosed in square
            brackets. The close square bracket (]) may be used in a set if
            it is the first character in the set. The fourth operation is
            the same as the logical not of the third operation and is
            specified the same way as the third with the addition of a
            caret character (^) at the beginning of the test string just
            inside the open square bracket. The final operation uses the
            backslash character to invalidate the special meaning of the
            open square bracket ([), the asterisk, backslash, or the
            question mark. Two backslashes in sequence will result in the
            evaluation of the backslash as a character with no special
            meaning.
          
          Barber                                              [Page 6]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            Implementers must be careful to apply the pattern-matching
            operators to whole characters encoded in UTF-8, and not to
            individual octets.
          
          5.1 Negating the wildmat pattern
          
            The exclamation point can be used at the beginning of a
            wildmat to negate it. That is, if the remainder of the pattern
            would match the string then the negated pattern does not, and
            vice versa. If it appears as any other character other than
            the first one, it has no special meaning.
          
          5.2 Examples
          
          
                 a) [^]-] -- matches any single character other than a
                    close square bracket or a minus sign/dash.
          
                 b) *bdc  -- matches any string that ends with the string
                    "bdc" including the string "bdc" (without quotes).
          
                 c) [0-9a-zA-Z] -- matches any single printable
                    alphanumeric ASCII character.
          
                 d) a??d  --  matches any four character string which
                    begins with a and ends with d.
          
                 e) !bc*d -- matches any string that does not start with
                    "bc" and end with "d" (without quotes)
                 f) !\\x  -- matches any string that does not start with
                    "\x" (without quotes)
          
          
          6. Format for Keyword Descriptions
          
            On the following pages are descriptions of each keyword
            recognized by the NNTP server and the responses that will be
            returned by those commands. These keywords are grouped by the
            functional step in which they are used.
          
            Each keyword is shown in upper case for clarity, although the
            NNTP server ignores case in the interpretation of commands.
          
            Parameters are shown as follows:
          
               o UPPERCASE    indicates literal text to be included in the
                 command;
          
               o lowercase    indicates a token described elsewhere;
          
               o [brackets]   indicate that the parameter is optional;
          
               o ellipsis...  indicates that the parameter may be repeated
                 any number of times (it must occur at least once);
          
               o vertical|bar indicates a choice of two mutually exclusive
                 parameters (exactly one must be provided).
          
          
          
          Barber                                              [Page 7]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            Parameters are case or language specific only when specified
            (either in this document or in RFC 1036[6]).
          
            The name "wildmat" for a parameter indicates that it is a
            wildmat format pattern as defined in section 5.
          
          
          7. The GREETING Step
          
          
          7.1 Initial Connection
          
            There is no keyword presented by the client upon initial
            connection to the server. The server MUST present an
            appropriate response code as a greeting to the client.  This
            response informs the client about what steps the client should
            take to reach the news exchange step.
          
            If the server will accept further commands from the client
            including POST, the server MUST present a 200 greeting code.
            If the server will accept further commands from the client,
            but it is not authorized to post articles using the POST
            command, the server MUST present a 201 greeting code.
            Otherwise the server MUST present a 400 or 502 greeting code
            and then immediately close the connection. 502 MUST be used if
            the client is not permitted under any circumstances to
            interact with the server and 400 otherwise.
          
          7.1.1 Initial Connection Example
          
            Example of a normal connection from an authorized client
          
                    [C] Initial TCP connection completed
          
                    [S] 200 NNTP Service Ready, posting permitted
          
            Client can send commands at this point. In this example, the
            client jumps directly to the conclusion step (See section 10).
          
                    [C] QUIT
          
                    [S] 205 NNTP Service exits normally
          
            Example of a normal connection from an unauthorized client
          
                    [C] Initial TCP connection completed
          
                    [S] 502 NNTP Service Unavailable
          
            At this point, the server closes the TCP connection.
          
          
          
          Barber                                              [Page 8]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            Example of a normal connection from an authorized client that
            is not permitted to post
          
                    [C] Initial TCP connection completed
          
                    [S] 201 NNTP Service Ready, posting prohibited
          
            Client can send commands at this point. In this example, the
            client jumps directly to the conclusion step (See section 10).
          
                    [C] QUIT
          
                    [S] 205 NNTP Service exits normally
          
          
          
            Example of a connection from any client where the server is
            unable to provide service
          
                    [C] Initial TCP connection completed
          
                    [S] 400 NNTP Service temporarily unavailable
          
            At this point, the server closes the TCP connection.
          
          
          7.2 MODE READER
          
            MODE READER
          
            MODE READER SHOULD be used by the client to indicate to the
            server that it is a newsreading client. This command may be
            entered at any time. The server MUST present a response (as
            described in section 7.1) appropriate to the server's ability
            to provide service to this client in this mode.
          
          7.2.1 Responses
          
                 200 Posting Permitted
          
                 201 Posting Not Permitted
          
                 400 Service temporarily unavailable
          
                 502 Service unavailable
          
            Following a 400 or 502 response the server MUST immediately
            close the connection.
          
            Note that the response need not be the same as the one
            presented during the initial greeting.
          
          
          7.2.2 MODE READER Examples
          
            Example of use of the MODE READER command by an authorized
            client
          
          Barber                                              [Page 9]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
                    [C] MODE READER
          
                    [S] 200 NNTP Service Ready, posting permitted
          
            Client can send commands at this point. In this example, the
            client jumps directly to the conclusion step (See section 10).
          
                    [C] QUIT
          
                    [S] 205 NNTP Service exits normally
          
          
          
            Example of use of MODE READER by a client not authorized to
            receive service from the server as a news reader
          
                    [C] MODE READER
          
                    [S] 502 Service Unavailable
          
            At this point, the server closes the TCP connection.
          
            Example of a normal connection from an authorized client that
            is not permitted to post
          
                    [C] MODE READER
          
                    [S] 201 NNTP Service Ready, posting prohibited
          
            Client can send commands at this point. In this example, the
            client jumps directly to the conclusion step (See section 10).
          
                    [C] QUIT
          
                    [S] 205 NNTP Service exits normally
          
          
          
            Example of a connection from any client where the server is
            unable to provide news reader service
          
                    [C] MODE READER
          
                    [S] 400 NNTP Service temporarily unavailable
          
            At this point, the server closes the TCP connection.
          
          
          8. The CAPABILITIES DISCOVERY Step
          
            A client NNTP that wishes to use extensions to NNTP can query
            the server to determine which extensions are available. This
            is done with the LIST EXTENSIONS command.
          
            If a particular extension is unavailable, the client can
            attempt to work around it or it may wish to terminate the
            session.
          
          Barber                                             [Page 10]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            See section 12 for further discussion of extensions.
          
          
          8.1 LIST EXTENSIONS
          
            The LIST EXTENSIONS command allows a client to determine which
            extensions are supported by the server.
          
            A client NNTP supporting NNTP service extensions SHOULD query
            the server early in the session for extensions session by
            issuing the LIST EXTENSIONS command. An NNTP Server that
            conforms to the specification in this document MUST give a
            successful response (see section 8.1.1), a failure response
            (see section 8.1.2), or an error response (see section 8.1.3).
            This command MAY be issued at anytime during a session.  It is
            not required that the client issues this command before
            attempting to make use of any extension. The response
            generated by this command MAY change during a session because
            of other state information. However, a client NNTP MUST NOT
            cache (for use in another session) any information returned if
            the LIST EXTENSIONS command succeeds. That is, a client NNTP
            is only able to get the current and correct information
            concerning available extensions during a session by issuing a
            LIST EXTENSIONS command during that session and processing
            that response.
          
          8.1.1 Successful response
          
            A successful response starts with a 202 code and is followed
            by a list of extension-labels, one per line. Each line MUST
            begin with exactly one space followed by an extension-label
            and optionally one or more parameters (separated by single
            spaces). The extension-label and the meaning of the parameters
            are specified as part of the definition of the extension. The
            extension-label MUST be in uppercase.
          
            The server MUST NOT list the same extension twice in the
            response, and MUST list all supported extensions. The order in
            which the extensions are listed is not significant. The server
            need not even consistently return the same order.
          
            The end of the list is defined by the usual period on a line
            by itself.
          
            A typical example reply to the LIST EXTENSIONS command might
            be a multiline reply of the form:
          
                    [C] LIST EXTENSIONS
          
          Barber                                             [Page 11]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
                    [S] 202 Extensions supported:
          
                    [S]  OVER
          
                    [S]  PAT
          
                    [S]  LISTGROUP
          
                    [S] .
          
          8.1.2 Failure response
          
            If for some reason the NNTP server is unable to list the
            service extensions it supports, it MUST return code 503. No
            list (not even an empty one) will be returned.
            In the case of a failure response, the client NNTP may try the
            extensions either as the need arises or configure itself for
            the basic NNTP functionality defined in this document.
          
          8.1.3 Error responses from extended servers
          
            If the NNTP server recognizes the LIST EXTENSIONS command, but
            due to various conditions cannot make any extensions available
            to the client at the time the client issued the LIST
            EXTENSIONS command, it MUST return code 402. No list (not even
            an empty one) will be returned.
          
            The client NNTP should configure itself for the basic NNTP
            functionality defined in this document, or issue commands that
            might change the state of the server, or issue the QUIT
            command (see section 10.1) if a particular extension is
            required for the client to properly operate.
          
            If the NNTP server determines that the NNTP service is no
            longer available (e.g., due to imminent system shutdown), it
            must return code 400. Note that this response code should not
            be generated due to an inactivity timeout as described in
            section 4.
          
            In the case of any error response outlined in this section,
            the client NNTP should issue the QUIT command (see section
            10.1). This will facilitate an orderly shutdown of the
            session.
          
          8.1.4 Responses from improperly implemented servers
          
          Barber                                             [Page 12]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            An NNTP server that improperly implements the LIST EXTENSIONS
            command may return an empty list. Clients SHOULD accommodate
            this protocol violation and interpret it as a response code
            402.
          
            The client NNTP should configure itself for the basic NNTP
            functionality defined in this document, or issue commands that
            might change the state of the server, or issue the QUIT
            command (see section 10.1) if a particular extension is
            required for the client to properly operate.
          
          
          9. The NEWS EXCHANGE Step
          
            During this step, two basic types of transactions occur:
          
               o article retrieval from the server
          
               o article posting to the server
          
          9.1 Article Retrieval
          
            News reading clients have available a variety of mechanisms to
            retrieve articles via NNTP. The news articles are stored and
            indexed using three types of keys. One key is the message id
            of an article. According to RFC 1036, this identifier should
            be globally unique. Another key is composed of the newsgroup
            name and the article number within that newsgroup. That key
            MUST be unique to a particular server (there will be only one
            article with that number within a particular newsgroup), but
            is not required to be globally unique.  Additionally, because
            the same article can be cross-posted to multiple newsgroups,
            there may be multiple keys that point to the same article on
            the same server. The final key is the arrival timestamp,
            giving the time that the article arrived at the server.
          
            The server MUST ensure that article numbers are issued in
            order of arrival timestamp; that is, articles arriving later
            MUST have higher numbers than those that arrive earlier. The
            server SHOULD allocate the next sequential unused number to
            each new article.
          
            Article numbers MUST lie between 1 and 4,294,967,295
            inclusive. The client and server SHOULD NOT use leading zeroes
            in specifying article numbers, and MUST NOT use more than 16
            digits. In some situations, the value zero replaces an article
            number to show some special situation.
          
          
          9.1.1 Article Retrieval by Newsgroup Name and Article Number
          
          Barber                                             [Page 13]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            The following commands are used to set the current newsgroup
            name and the "current article pointer" which is used by other
            commands for article retrieval. At the start of a NNTP
            session, both of these values are undefined.
          
          
          9.1.1.1 GROUP
          
            GROUP ggg
          
            The required parameter ggg is the name of the newsgroup to be
            selected (e.g. "news.software.b"). A list of valid newsgroups
            may be obtained by using the LIST keyword.  See section 9.4
            for more information on the LIST keyword.
          
            The successful selection response will return the article
            numbers of the first and last articles in the group at the
            moment of selection (these numbers are referred to as the
            "reported low water mark" and the "reported high water mark"),
            and an estimate of the number of articles on file in the
            group.
          
            If the group is not empty, the estimate MUST be at least the
            actual number of articles available, and MUST be no greater
            than one more than the difference between the reported low and
            high water marks. (Some implementations will actually count
            the number of articles on file. Others will just subtract the
            low water mark from the high water mark and add one to get an
            estimate.)
          
            If the group is empty, one of the following three situations
            will occur. Clients MUST accept all three cases; servers MUST
            NOT represent an empty group in any other way.
          
               o The high water mark will be one less than the low water
                 mark, and the estimated article count will be zero.
                 Servers SHOULD use this method to show an empty group.
                 This is the only time that the high water mark can be
                 less than the low water mark.
          
               o All three numbers will be zero.
          
               o The high water mark is greater than or equal to the low
                 water mark; the estimated article count might be zero or
                 non-zero; if non-zero, the same requirements apply as for
                 a non-empty group.
          
            The set of articles in a group may change after the GROUP
            command is carried out. That is:
          
               o articles may be removed from the group
          
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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
               o articles may be reinstated in the group with the same
                 article number, but those articles MUST have numbers no
                 less than the reported low water mark (note that this is
                 a reinstatement of the previous article, not a new
                 article reusing the number)
          
               o new articles may be added with article numbers greater
                 than the reported high water mark (if an article that was
                 the one with the highest number has been removed, the
                 next new article will not have the number one greater
                 than the reported high water mark)
          
            Except when the group is empty and all three numbers are zero,
            whenever a subsequent GROUP command for the same newsgroup is
            issued, either by the same client or a different client, the
            reported low water mark in the response MUST be no less than
            that in any previous response for that newsgroup sent to any
            client. The client may make use of the low water mark to
            remove all remembered information about articles with lower
            numbers, as these will never recur. This includes the
            situation when the high water mark is one less than the low
            water mark.
          
            No similar assumption can be made about the high water mark,
            as this can decrease if an article is removed, and then
            increase again if it is reinstated or if new articles arrive.
            When a valid group is selected by means of this command, the
            internally maintained "current article pointer" MUST be set to
            the first article in the group and the name of the current
            newsgroup MUST be set to the selected newsgroup name. If an
            invalid group is specified, the previously selected group, if
            any, and article MUST remain selected. If an empty newsgroup
            is selected, the "current article pointer" is in an
            indeterminate state and MUST NOT be used.
          
            The GROUP keyword (or the LISTGROUP keyword, if implemented)
            MUST be used by a client and a successful response received
            before the any other command is used that depends on having
            the "current article pointer" be valid.
          
          9.1.1.1.1 Responses
          
                 211 n f l s group selected
                 (n = estimated number of articles in group, f = first
                    article number in the group, l = last article number
                    in the group, s = name of the group.)
          
          
          
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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
                 411 no such newsgroup
          
          
          9.1.1.1.2 GROUP Examples
          
            Example for a group known to the server
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
            Example for a group unknown to the server
          
                    [C] GROUP example.is.sob.bradner.or.barber
          
                    [S] 411 example.is.sob.bradner.or.barber is unknown
          
          
          9.1.1.2   LAST
          
            LAST
          
            If the current newsgroup is valid, the internally maintained
            "current article pointer" MUST be set to the previous article
            in the current newsgroup.  If already positioned at the first
            article of the newsgroup, an error message MUST be returned
            and the current article MUST remain selected.
          
            There MAY be no previous article in the group, although the
            current article number is not the reported low water mark.
            There MUST NOT be a previous article when the current article
            number is the reported low water mark.
          
            Because articles can be removed and added, the results of
            multiple LAST and NEXT commands MAY not be consistent over the
            life of a particular NNTP session.
          
            If successful, a response indicating the current article
            number and a message-id string MUST be returned. No article
            text is sent in response to this command.
          
          9.1.1.2.1 Responses
          
                 223 n a article retrieved - request text separately (n =
                    article number, a = unique article id)
          
                 412 no newsgroup selected
          
                 420 no current article has been selected
          
                 422 no previous article in this group
          
          Barber                                             [Page 16]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
          9.1.1.2.2 LAST Examples
          
            Example of a successful article retrieval using LAST
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] NEXT
          
                    [S] 223 3000237 <668929@domain.com> retrieved
          
                    [C] LAST
          
                    [S] 223 3000234 <45223423@to.to> retrieved
          
          
          
            Example of an attempt to retrieve an article without having
            selected a group (via the GROUP command) first
          
                    [S] 200 NNTP Service ready
          
                    [C] LAST
          
                    [S] 412 no newsgroup selected
          
          
          
            Example of an attempt to retrieve an article using the LAST
            command when the current article pointer is pointing at the
          
            first article in the group
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] LAST
          
                    [S] 422 No previous article to retrieve
          
          
          
            Example of an attempt to retrieve an article using the LAST
            command when the current group selected is empty
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP example.empty.newsgroup
          
                    [S] 211 0 0 0 example.empty.newsgroup
          
                    [C] LAST
          
                    [S] 420 No current article selected
          
          
          9.1.1.3 NEXT
          
            NEXT
          
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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            If the current newsgroup is valid, the internally maintained
            "current article pointer" MUST be advanced to the next article
            in the current newsgroup.  If no more articles remain in the
            current group, an error message MUST be returned and the
            current article MUST remain selected.
          
            If successful, a response indicating the current article
            number and the message-id string MUST be returned.  No article
            text is sent in response to this command.
          
          9.1.1.3.1 Responses
          
                 223 n a article retrieved - request text separately (n =
                    article number, a = unique article id)
          
                 412 no newsgroup selected
          
                 420 no current article has been selected
          
                 421 no next article in this group
          
          
          9.1.1.3.2 NEXT Examples
          
            Example of a successful article retrieval using NEXT
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] NEXT
          
                    [S] 223 3000237 <668929@domain.com> retrieved
          
            Example of an attempt to retrieve an article without having
            selected a group (via the GROUP command) first
          
                    [S] 200 NNTP Service ready
          
                    [C] NEXT
          
                    [S] 412 no newsgroup selected
          
            Example of an attempt to retrieve an article using the NEXT
            command when the current article pointer is pointing at the
            last article in the group
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
          
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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
                    [C] ARTICLE 3002322
          
                    [S] 220 3002322 <411@whitehouse.gov> retrieved
          
                    [S] Path: pathost!demo!whitehouse!not-for-mail
          
                    [S] From: nobody@whitehouse.gov(Demo User)
          
                    [S] Newsgroups: misc.test
          
                    [S] Subject: I am just a test article
          
                    [S] Date: 6 Oct 1998 04:38:40 -0500
          
                    [S] Organization: The White House, Washington, DC
          
                    [S] Message-ID: <411@whitehouse.gov>
          
                    [S]
          
                    [S] This is just a test article.
          
                    [S] .
          
                    [C] NEXT
          
                    [S] 422 No next article to retrieve
          
          
          
            Example of an attempt to retrieve an article using the NEXT
            command when the current group selected is empty
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP example.empty.newsgroup
          
                    [S] 211 0 0 0 example.empty.newsgroup
          
                    [C] NEXT
          
                    [S] 420 No current article selected
          
          
          
          
          9.2 Retrieval of Articles and Article Sections
          
            The ARTICLE, BODY, HEAD, and STAT commands are very similar.
            They differ only in the parts of the article that are
            presented to the client and in the successful response code.
            The ARTICLE command is described here in full, while the other
            commands are described in terms of the differences.
            An article, as defined by RFC 1036, consists of two parts: the
            article headers and the article body. When responding to one
            of these commands, the server presents the entire article or
            appropriate part and does not attempt to alter or translate it
            in any way.
          
          
          
          
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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
          9.2.1 ARTICLE
          
          
          
            ARTICLE <message-id>
          
            ARTICLE [number]
          
            The ARTICLE command selects an article based on the arguments
            and presents the header, a blank line, and the body of that
            article. The command has two forms.
          
            In the first form, a message-id is specified (including the
            angle brackets), and the server presents the article with that
            message-id in its headers. In this case, the server MUST NOT
            alter the "current article pointer". This is both to
            facilitate the presentation of articles that may be referenced
            within another article being read, and because of the semantic
            difficulties of determining the proper sequence and membership
            of an article which may have been posted to more than one
            newsgroup.
          
            In the second form, an article number may be specified. If so,
            and if there is an article with that number in the currently
            selected group, the server MUST set the current article
            pointer to that number.
          
            Then, whether or not a number was specified, the article
            indicated by the current article pointer is presented to the
            client.
          
            Note that a previously valid article number MAY become invalid
            if the article has been removed. A previously invalid article
            number MAY become valid if the article has been reinstated,
            but such an article number MUST be no less than the reported
            low water mark for that group.
          
            The server MUST NOT change the currently selected group as a
            result of this command. The server MUST NOT change the current
            selected article except when an article number argument was
            provided and the article exists; in particular, it MUST NOT
            change it following an unsuccessful response.
          
          
          9.2.1.1 Responses
          
                 First form (message-id specified):
          
                 220 0 a     article retrieved and follows (multiline, a =
                    unique article id)
          
                 430         no such article
          
                 502         service unavailable
          
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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
                 Second form (optional article number specified):
          
                 220 n a     article retrieved and follows (multiline, n =
                    article number, a = unique article id)
          
                 412         no newsgroup selected
          
                 420         no current article selected
          
                 423         no such article number in this group
          
                 502         service unavailable
          
            The 420 response only occurs if no article number has been
            specified.
          
            In the 220 response, the first parameter is 0 for the first
            form and the article number (within the current group) for the
            second form. The second parameter is the message-id of the
            article (within angle brackets). This is taken from the
            message-id header line of the article (required by RFC 1036).
          
            If there is no such line, the message-id "<0>" MUST be used
            instead (without the double quotes).
          
            Since the message-id field is unique for each article, it may
            be used by a client to skip duplicate displays of articles
            that have been posted more than once, or to more than one
            newsgroup.
          
            The article headers and body are returned as a multiline
            response following the initial response line.
          
          
          9.2.1.2 Examples
          
            Example of a successful retrieval of an article (using no
            article number)
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] ARTICLE
          
                    [S] 220 3000234 <45223423@to.to>
          
                    [S] Path: pathost!demo!somewhere!not-for-mail
          
                    [S] From: nobody@nowhere.to (Demo User)
          
                    [S] Newsgroups: misc.test
          
                    [S] Subject: I am just a test article
          
                    [S] Date: 6 Oct 1998 04:38:40 -0500
          
                    [S] Organization: Nowhere, To
          
                    [S] Message-ID: <45223423@to.to>
          
          
          
          
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          INTERNET DRAFT                                          S. Barber
          
          Expires: June 30, 2001                 Academ Consulting Services
          
                                                              November 2000
          
                    [S]
          
                    [S] This is just a test article.
          
                    [S] .
          
            Example of a successful retrieval of an article by message-id
          
                    [S] 200 NNTP Service Ready
          
                    [C] ARTICLE <45223423@to.to>
          
                    [S] 220 0 <45223423@to.to>
          
                    [S] Path: pathost!demo!somewhere!not-for-mail
          
                    [S] From: nobody@nowhere.to (Demo User)
          
                    [S] Newsgroups: misc.test
          
                    [S] Subject: I am just a test article
          
                    [S] Date: 6 Oct 1998 04:38:40 -0500
          
                    [S] Organization: Nowhere, To
          
                    [S] Message-ID: <45223423@to.to>
          
                    [S]
          
                    [S] This is just a test article.
          
                    [S] .
          
            Example of an unsuccessful retrieval of an article by message-
            id
          
                    [S] 200 NNTP Service Ready
          
                    [C] ARTICLE <i.am.not.there@nowhere.to>
          
                    [S] 430 No Such Article Found
          
            Example of an unsuccessful retrieval of an article by number
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 news.groups
          
                    [C] ARTICLE 300256
          
                    [S] 423 No such article number in this group
          
            Example of an unsuccessful retrieval of an article by number
            because no newsgroup was selected first
          
                    [S] 200 NNTP Service Ready
          
                    [C] ARTICLE 300256
          
                    [S] 412 No newsgroup selected
          
          
          
          
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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            Example of an attempt to retrieve an article when the current
            group selected is empty
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP example.empty.newsgroup
          
                    [S] 211 0 0 0 example.empty.newsgroup
          
                    [C] ARTICLE
          
                    [S] 420 No current article selected
          
            Example of a failure due to the service being unavailable
          
                    [S] 200 NNTP Service Ready
          
                    [C] ARTICLE <i.am.a.test.article@nowhere.to>
          
                    [S] 502 Service unavailable
          
          
          
          
          9.2.2 HEAD
          
            HEAD <message-id>
          
            HEAD [number]
          
            The HEAD command behaves identically to the ARTICLE command
            except that, if the article exists, only the headers are
            presented (the blank line separating the headers and body MUST
            NOT be included).
          
          9.2.2.1 Responses
          
                 First form (message-id specified):
          
                 221 0 a     article retrieved, headers follow (multiline)
          
                 430         no such article
          
                 502         service unavailable
          
                 Second form (optional article number specified):
          
                 221 n a     article retrieved, headers follow (multiline)
          
                 412         no newsgroup selected
          
                 420         no current article selected
          
                 423         no such article number in this group
          
                 502         service unavailable
          
          
          
            Except that only the headers are included in the response, the
            221 response behaves identically to the 220 response of the
            ARTICLE command.
          
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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
          9.2.2.2 Examples
          
            Example of a successful retrieval of the headers in an article
            (using no article number)
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] HEAD
          
                    [S] 220 3000234 <45223423@to.to>
          
                    [S] Path: pathost!demo!somewhere!not-for-mail
          
                    [S] From: nobody@nowhere.to (Demo User)
          
                    [S] Newsgroups: misc.test
          
                    [S] Subject: I am just a test article
          
                    [S] Date: 6 Oct 1998 04:38:40 -0500
          
                    [S] Organization: Nowhere, To
          
                    [S] Message-ID: <45223423@to.to>
          
                    [S] .
          
            Example of a successful retrieval of the headers in an article
            by message-id
          
                    [S] 200 NNTP Service Ready
          
                    [C] HEAD <45223423@to.to>
          
                    [S] 220 0 <45223423@to.to>
          
                    [S] Path: pathost!demo!somewhere!not-for-mail
          
                    [S] From: nobody@nowhere.to (Demo User)
          
                    [S] Newsgroups: misc.test
          
                    [S] Subject: I am just a test article
          
                    [S] Date: 6 Oct 1998 04:38:40 -0500
          
                    [S] Organization: Nowhere, To
          
                    [S] Message-ID: <45223423@to.to>
          
                    [S] .
          
            Example of an unsuccessful retrieval of the header of an
            article by message-id
          
                    [S] 200 NNTP Service Ready
          
                    [C] HEAD <i.am.not.there@nowhere.to>
          
                    [S] 430 No Such Article Found
          
          
          
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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
            Example of an unsuccessful retrieval of the header of an
            article by number
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] HEAD 300256
          
                    [S] 423 No such article number in this group
          
            Example of an unsuccessful retrieval the header of an article
            by number because no newsgroup was selected first
          
                    [S] 200 NNTP Service Ready
          
                    [C] HEAD 300256
          
                    [S] 412 No newsgroup selected
          
            Example of an attempt to retrieve the header of an article
            when the current group selected is empty
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP example.empty.newsgroup
          
                    [S] 211 0 0 0 example.empty.newsgroup
          
                    [C] HEAD
          
                    [S] 420 No current article selected
          
            Example of a failure due to the service being unavailable
          
                    [S] 200 NNTP Service Ready
          
                    [C] HEAD <i.am.a.test.article@nowhere.to>
          
                    [S] 502 Service unavailable
          
          
          9.2.3 BODY
          
            BODY <message-id>
          
            BODY [number]
          
            The BODY command behaves identically to the ARTICLE command
            except that, if the article exists, only the body is presented
            (the blank line separating the headers and body MUST NOT be
            included).
          
          9.2.3.1 Responses
          
                 First form (message-id specified):
          
                 222 0 a     article retrieved, body follows (multiline)
          
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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
                 430         no such article
          
                 502         service unavailable
          
                 Second form (optional article number specified):
          
                 222 n a     article retrieved, body follows (multiline)
          
                 412         no newsgroup selected
          
                 420         no current article selected
          
                 423         no such article number in this group
          
                 502         service unavailable
          
          
          
            Except that only the body is included in the response, the 222
            response behaves identically to the 220 response of the
            ARTICLE command.
          
          
          9.2.3.2 Examples
          
            Example of a successful retrieval of the body of an article
            (using no article number)
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] BODY
          
                    [S] 222 3000234 <45223423@to.to>
          
                    [S] This is just a test article.
          
                    [S] .
          
            Example of a successful retrieval of the body of an article by
            message-id
          
                    [S] 200 NNTP Service Ready
          
                    [C] BODY <45223423@to.to>
          
                    [S] 222 0 <45223423@to.to>
          
                    [S] This is just a test article.
          
                    [S] .
          
            Example of an unsuccessful retrieval of the body of an article
            by message-id
          
                    [S] 200 NNTP Service Ready
          
                    [C] BODY <i.am.not.there@nowhere.to>
          
                    [S] 430 No Such Article Found
          
            Example of an unsuccessful retrieval of the body of an article
            by number
          
          
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          INTERNET DRAFT                                          S. Barber
          
          Expires: June 30, 2001                 Academ Consulting Services
          
                                                              November 2000
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] BODY 300256
          
                    [S] 423 No such article number in this group
          
            Example of an unsuccessful retrieval of the body of an article
            by number because no newsgroup was selected first
          
                    [S] 200 NNTP Service Ready
          
                    [C] BODY 300256
          
                    [S] 412 No newsgroup selected
          
            Example of an attempt to retrieve the body of an article when
            the current group selected is empty
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP example.empty.newsgroup
          
                    [S] 211 0 0 0 example.empty.newsgroup
          
                    [C] BODY
          
                    [S] 420 No current article selected
          
            Example of a failure due to the service being unavailable
          
                    [S] 200 NNTP Service Ready
          
                    [C] BODY <i.am.a.test.article@nowhere.to>
          
                    [S] 502 Service unavailable
          
          
          9.2.4 STAT
          
            STAT <message-id>
          
            STAT [number]
          
            The STAT command behaves identically to the ARTICLE command
            except that, if the article exists, it is NOT presented to the
            client.
          
            This command allows the client to determine whether an article
            exists, and in the second form what its message-id is, without
            having to process an arbitrary amount of text.
          
          
          9.2.4.1 Responses
          
                 First form (message-id specified):
          
                 223 0 a     article exists
          
                 430         no such article
          
          
          
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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
                 502         service unavailable
          
                 Second form (optional article number specified):
          
                 223 n a     article exists
          
                 412         no newsgroup selected
          
                 420         no current article selected
          
                 423         no such article number in this group
          
                 502         service unavailable
          
          
          
            The parameters of the 223 response are identical to those that
            would have been given in a 220 response to the equivalent
            ARTICLE command. However, the response is NOT multiline.
          
          
          9.2.4.2 Examples
          
            Example of STAT on an existing article (using no article
            number)
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] STAT
          
                    [S] 223 3000234 <45223423@to.to>
          
            Example of a STAT of an existing article by message-id
          
                    [S] 200 NNTP Service Ready
          
                    [C] STAT <45223423@to.to>
          
                    [S] 223 0 <45223423@to.to>
          
            Example of an STAT of an article not on the server by message-
            id
          
                    [S] 200 NNTP Service Ready
          
                    [C] STAT <i.am.not.there@nowhere.to>
          
                    [S] 430 No Such Article Found
          
            Example of STAT of an article not in the server by number
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
          
          
          
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          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
                    [C] STAT 300256
          
                    [S] 423 No such article number in this group
          
            Example of STAT of an article by number when no newsgroup was
            selected first
          
                    [S] 200 NNTP Service Ready
          
                    [C] STAT 300256
          
                    [S] 412 No newsgroup selected
          
            Example of STAT of an article when the current group selected
            is empty
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP example.empty.newsgroup
          
                    [S] 211 0 0 0 example.empty.newsgroup
          
                    [C] STAT
          
                    [S] 420 No current article selected
          
            Example of a failure due to the service being unavailable
          
                    [S] 200 NNTP Service Ready
          
                    [C] STAT <i.am.a.test.article@nowhere.to>
          
                    [S] 502 Service unavailable
          
          
          
          
          9.3 Article Posting
          
            Article posting is done in one of two modes: individual
            article posting from news reading clients and article transfer
            from other news servers.
          
          
          9.3.1 POST
          
            POST
          
            If posting is allowed, response code 340 MUST be returned to
            indicate that the article to be posted should be sent.
          
            Response code 440 MUST be sent if that posting is prohibited
            for some installation-dependent reason.
          
            If posting is permitted, the article MUST be presented to the
            server by the client in the format specified by RFC 1036. The
            text forming the header and body of the message to be posted
            MUST be sent by the client using the conventions for text
            received from the news server: A single period (".") on a line
            indicates the end of the text, with lines starting with a
          
          
          
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            period in the original text having that period doubled during
            transmission.
          
            Following the presentation of the termination sequence by the
            client, the server MUST return a response code indicating
            success or failure of the article transfer. Note that response
            codes 340 and 440 are used in direct response to the POST
            command. Others are returned following the sending of the
            article.
          
            No attempt shall be made by the server to filter characters,
            fold or limit lines, or otherwise process incoming text. The
            intent is that the server just passes the incoming message to
            be posted to the server installation's news posting software,
            which is not part of this specification.
          
          9.3.1.1 Responses
          
                 240 article received ok
          
                 340 send article to be posted. End with <CR-LF>.<CR-LF>
          
                 440 posting not allowed
          
                 441 posting failed
          
          9.3.1.2 Examples
          
            Example of a successful posting
          
                    [S] 200 NNTP Service Ready
          
                    [C] POST
          
                    [S] 340 Input article. End with <CR-LF>.<CR-LF>
          
                    [C] From: demo@testdomain.com(Demo User)
          
                    [C] Newsgroups: misc.test
          
                    [C] Subject: I am just a test article
          
                    [C] Organization: Testdomain, USA
          
                    [C]
          
                    [C] This is just a test article.
          
                    [C] .
          
                    [S] 240 Article received ok
          
            Example of an unsuccessful posting
          
                    [S] 200 NNTP Service Ready
          
                    [C] POST
          
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                    [S] 340 Input article. End with <CR-LF>.<CR-LF>
          
                    [C] From: demo@testdomain.com(Demo User)
          
                    [C] Newsgroups: misc.test
          
                    [C] Subject: I am just a test article
          
                    [C] Organization: Testdomain, USA
          
                    [C]
          
                    [C] This is just a test article.
          
                    [C] .
          
                    [S] 441 Posting failed
          
            Example of an attempt to posting when posting is not allowed
          
                    [S] 201 NNTP Service Ready, read-only
          
                    [C] POST
          
                    [S] 440 Posting not permitted
          
          
          
          
          9.3.2 IHAVE
          
          
          
            IHAVE <message-id>
          
            The IHAVE command informs the server that the client has an
            article whose id is <message-id>. If the server desires a copy
            of that article, it MUST return a response instructing the
            client to send the entire article. If the server does not want
            the article (if, for example, the server already has a copy of
            it), a response indicating that the article is not wanted MUST
            be returned.
          
            If transmission of the article is requested, the client MUST
            send the entire article, including header and body, in the
            manner specified for text transmission from the server. The
            server MUST return a response code indicating success or
            failure of the transferal of the article.
          
            This function differs from the POST command in that it is
            intended for use in transferring already-posted articles
            between hosts. It SHOULD NOT be used when the client is a
            personal news reading program. In particular, this function
            will invoke the server's news posting program with the
            appropriate settings (flags, options, etc.) to indicate that
            the forthcoming article is being forwarded from another host.
          
            However, the server MAY elect not to post or forward the
            article if after further examination of the article it deems
          
          
          
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            it inappropriate to do so. Reasons for such subsequent
            rejection of an article may include such problems as
            inappropriate newsgroups or distributions, disk space
            limitations, article lengths, garbled headers, and the like.
            These are typically restrictions enforced by the server host's
            news software and not necessarily the NNTP server itself.
          
          9.3.2.1 Responses
          
                 235 article transferred ok
          
                 335 send article to be transferred.  End with <CR-
                 LF>.<CR-LF>
          
                 435 article not wanted - do not send it
          
                 436 transfer failed - try again later
          
                 437 article rejected - do not try again
          
            Because some host news posting software may not be able to
            immediately render status on the whether an article is
            inappropriate for posting or forwarding, an NNTP server MAY
            acknowledge the successful transfer of the article and later
            silently discard it. Thus, an NNTP server MAY return the 235
            acknowledgment code and later discard the received article.
          
          
          9.3.2.2 Examples
          
            Example of successfully sending an article to another site
          
                    [S] 200 NNTP Service Ready
          
                    [C] IHAVE <i.am.an.article.you.will.want@nowhere.to>
          
                    [S] 335 Send it. End with <CR-LF>.<CR-LF>
          
                    [C] Path: pathost!demo!somewhere!not-for-mail
          
                    [C] From: nobody@nowhere.to (Demo User)
          
                    [C] Newsgroups: misc.test
          
                    [C] Subject: I am just a test article
          
                    [C] Date: 6 Oct 1998 04:38:40 -0500
          
                    [C] Organization: Nowhere, To
          
                    [C] Message-ID: <i.am.a.test.article@nowhere.to>
          
                    [C]
          
                    [C] This is just a test article.
          
                    [C] .
          
                    [S] 235 Article transferred ok
          
          
          
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          INTERNET DRAFT                                          S. Barber
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            Example of sending an article to another site that rejects it
          
                    [S] 200 NNTP Service Ready
          
                    [C] IHAVE <i.am.an.article.you.will.want@nowhere.to>
          
                    [S] 335 Send it. End with <CR-LF>.<CR-LF>
          
                    [C] Path: pathost!demo!somewhere!not-for-mail
          
                    [C] From: nobody@nowhere.to (Demo User)
          
                    [C] Newsgroups: misc.test
          
                    [C] Subject: I am just a test article
          
                    [C] Date: 6 Oct 1998 04:38:40 -0500
          
                    [C] Organization: Nowhere, To
          
                    [C] Message-ID: <i.am.a.test.article@nowhere.to>
          
                    [C]
          
                    [C] This is just a test article.
          
                    [C] .
          
                    [S] 437 Article rejected. Don't send again
          
          
          
            Example of sending an article to another site where the
            transfer fails
          
                    [S] 200 NNTP Service Ready
          
                    [C] IHAVE <i.am.an.article.you.will.want@nowhere.to>
          
                    [S] 335 Send it. End with <CR-LF>.<CR-LF>
          
                    [C] Path: pathost!demo!somewhere!not-for-mail
          
                    [C] From: nobody@nowhere.to (Demo User)
          
                    [C] Newsgroups: misc.test
          
                    [C] Subject: I am just a test article
          
                    [C] Date: 6 Oct 1998 04:38:40 -0500
          
                    [C] Organization: Nowhere, To
          
                    [C] Message-ID: <i.am.a.test.article@nowhere.to>
          
                    [C]
          
                    [C] This is just a test article.
          
                    [C] .
          
                    [S] 436 Transfer failed
          
          
          
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            Example of sending an article to another site that rejects it
          
                    [S] 200 NNTP Service Ready
          
                    [C] IHAVE <i.am.an.article.you.will.want@nowhere.to>
          
                    [S] 335 Send it. End with <CR-LF>.<CR-LF>
          
                    [C] Path: pathost!demo!somewhere!not-for-mail
          
                    [C] From: nobody@nowhere.to (Demo User)
          
                    [C] Newsgroups: misc.test
          
                    [C] Subject: I am just a test article
          
                    [C] Date: 6 Oct 1998 04:38:40 -0500
          
                    [C] Organization: Nowhere, To
          
                    [C] Message-ID: <i.am.a.test.article@nowhere.to>
          
                    [C]
          
                    [C] This is just a test article.
          
                    [C] .
          
                    [S] 435 Don't send it again
          
          
          9.4 The LIST Keyword
          
          9.4.1 LIST
          
            LIST [ACTIVE [wildmat]]
          
            The response to the LIST keyword with no parameters returns a
            list of valid newsgroups and associated information.  Each
            newsgroup is sent as a line of text in the following format:
          
               group first last status
          
            where <group> is the name of the newsgroup, <last> is the
            number of the last known article currently in that newsgroup,
            <first> is the number of the first article currently in the
            newsgroup, and <status> indicates the current status of the
            group on this server. Typically, the <status> will be consist
            of the US-ASCII character 'y' where posting is permitted, 'n'
            where posting is not permitted and 'm' where postings will be
            forwarded to the newsgroup moderator by the news server. Other
            status strings may exist. The definition of these other values
            and the circumstances under which they are returned is covered
            in other specifications.
          
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            The <first> and <last> fields will always be numeric.  They
            may have leading zeros. The <first> field corresponds to the
            "reported low water mark" and the <last> field corresponds to
            the "reported high water mark" described in the GROUP command
            (see Section 9.1.1.1).
          
            The status of a newsgroup only indicates how posts to that
            newsgroup are processed. It does not indicate if the current
            client is permitted to post. That is indicated by the status
            code returned as part of the greeting.
          
            Please note that an empty list (i.e., the text body returned
            by this command consists only of the terminating period) is a
            possible valid response, and indicates that there are
            currently no valid newsgroups.
          
            If the optional wildmat parameter is specified, the list is
            limited to only the groups that match the pattern.
          
            Specifying a single group is usually very efficient for the
            server. Multiple groups may be specified by using wildmat
            patterns (described in section 5).
          
          
          9.4.1.1 Responses
          
                 215 list of newsgroups follows
          
          
          9.4.1.2 Examples
          
          Example of LIST returning a list of newsgroups
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST
          
                    [S] 215 list of newsgroups follows
          
                    [S] misc.test 3000234 3002322 y
          
                    [S] alt.fc-writers.recovery 1 4 y
          
                    [S] tx.natives.recovery 56 89 y
          
                    [S] .
          
            Example of LIST returning no newsgroups
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST
          
                    [S] 215 list of newsgroups follows
          
                    [S] .
          
          
          
          
          
          
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          9.4.2 LIST ACTIVE.TIMES
          
          
          
            LIST ACTIVE.TIMES [wildmat]
          
            The active.times file is maintained by some news transport
            systems to contain information about who created a particular
            newsgroup and when. The format of this file includes three
            fields. The first field is the name of the newsgroup. The
            second is the time when this group was created on this news
            server measured in seconds since the start of January 1, 1970.
            The third is the email address of the entity that created the
            newsgroup. When executed, the information is displayed
            following the 215 response. When display is completed, the
            server will send a period on a line by itself. If the
            information is not available, the server will return the 503
            error response. If the server does not recognize the command,
            it SHOULD return the 501 error response.
          
            If the optional wildmat parameter is specified, the list is
            limited to only the groups that match the pattern.
          
            Specifying a single group is usually very efficient for the
            server. Multiple groups may be specified by using wildmat
            patterns (described in section 5).
          
          9.4.2.1 Responses
          
                 215 information follows
          
                 501 Syntax error
          
                 503 program error, function not performed
          
          
          9.4.2.2 Examples
          
          Example of LIST ACTIVE.TIMES returning a list of newsgroups
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST ACTIVE.TIMES
          
                    [S] 215 information follows
          
                    [S] misc.test 930445408 <creatme@isc.org>
          
                    [S] alt.rfc-writers.recovery 930562309 <m@nowhere.to>
          
                    [S] tx.natives.recovery 930678923 <sob@academ.com>
          
                    [S]  .
          
          
          
          
          
          
          
          
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            Example of LIST ACTIVE.TIMES returning an error (The server
            software is not configured to maintain this information, but
            does recognize the command as valid.)
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST ACTIVE.TIMES
          
                    [S] 503 program error, function not performed
          
            Example of LIST ACTIVE.TIMES sent to a server that does not
            recognize this argument (e.g. The software does not maintain
            this information.)
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST ACTIVE.TIMES
          
                    [S] 501 Syntax Error
          
          
          9.4.3 LIST DISTRIBUTIONS
          
            LIST DISTRIBUTIONS
          
            The distributions file is maintained by some news transport
            systems to contain information about valid values for the
            Distribution: line in a news article header and about what the
            values mean. Each line contains two fields, the value and a
            short explanation on the meaning of the value. When executed,
            the information is displayed following the 215 response. When
            display is completed, the server will send a period on a line
            by itself. If the information is not available, the server
            will return the 503 error response. If the server does not
            recognize this command, it SHOULD return the 501 error
            response.
          
          
          9.4.3.1 Responses
          
                 215 information follows
          
                 501 Syntax error
          
                 503 program error, function not performed
          
          
          9.4.3.2 Examples
          
          Example of LIST DISTRIBUTIONS returning a list of newsgroups
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST DISTRIBUTIONS
          
                    [S] 215 information follows
          
                    [S] usa United States of America
          
          
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                    [S] na North America
          
                    [S] world All over the World
          
                    [S] .
          
            Example of LIST DISTRIBUTIONS returning an error (e.g. The
            server software is not configured to maintain this
            information, but does recognize the command as valid.)
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST DISTRIBUTIONS
          
                    [S] 503 program error, function not performed
          
            Example of LIST DISTRIBUTIONS sent to a server that does not
            recognize the command (e.g. The server does not maintain this
            information regardless of configuration.)
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST DISTRIBUTIONS
          
                    [S] 501 Syntax Error
          
          
          9.4.4 LIST DISTRIB.PATS
          
            LIST DISTRIB.PATS
          
            The distrib.pats file is maintained by some news transport
            systems to allow clients to choose a value for the
            Distribution: line in the header of a news article being
            posted. The information returned consists of lines, in no
            particular order, each of which contains three fields
            separated by colons. These fields are a weight, a group name
            or wildmat pattern, and a Distribution: value, in that order.
          
            The client MAY use this information to select a Distribution:
            value based on the name of a newsgroup. To do so, it should
            determine the lines whose second field matches the newsgroup
            name, select that line with the highest weight (with 0 being
            the lowest), and use the Distribution: field from that line.
          
            When executed, the information is displayed following the 215
            response.  When display is completed, the server will send a
            period on a line by itself. If the information is not
            available, the server will return the 503 error response. If
            this command is not recognized, the server SHOULD return the
            501 error response.
          
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          9.4.4.1 Responses
          
                 215 information follows
          
                 501 Syntax error
          
                 503 program error, function not performed
          
          
          9.4.4.2 Examples
          
          Example of LIST DISTRIB.PATS returning a list of newsgroups
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST DISTRIB.PATS
          
                    [S] 215 information follows
          
                    [S] 10:local.*:local
          
                    [S] .
          
            Example of LIST DISTRIB.PATS returning an error (e.g. The
            server software is not configured to maintain this
            information, but does recognize the command as valid.)
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST DISTRIB.PATS
          
                    [S] 503 program error, function not performed
          
            Example of LIST DISTRIB.PATS sent to a server that does not
            recognize the command (e.g. The software does not maintain
            this information regardless of configuration.)
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST DISTRIB.PATS
          
                    [S] 501 Syntax Error
          
          
          9.4.5 LIST NEWSGROUPS
          
               LIST NEWSGROUPS [wildmat]
          
               The newsgroups file is maintained by some news transport
               systems to contain the name of each newsgroup that is
               active on the server and a short description about the
               purpose of each newsgroup. Each line in the file contains
               two fields, the newsgroup name and a short explanation of
               the purpose of that newsgroup. When executed, the
               information is displayed following the 215 response. When
               display is completed, the server will send a period on a
               line by itself. If the information is not available, the
               server will return the 503 response. If the server does not
          
          
          
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               recognize the command it should return a 501 response. If
               the optional matching parameter is specified, the list is
               limited to only the groups that match the pattern (no
               matching is done on the group descriptions).  Specifying a
               single group is usually very efficient for the server, and
               multiple groups may be specified by using a wildmat(see
               section 5), not regular expressions. If nothing is matched
               an empty list is returned, not an error.
          
          
          9.4.5.1 Responses
          
                 215 information follows
          
                 501 Syntax error
          
                 503 program error, function not performed
          
          
          9.4.5.2 Examples
          
             Example of LIST NEWSGROUPS returning a list of newsgroups
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST NEWSGROUPS
          
                    [S] 215 information follows
          
                    [S] misc.test General Usenet testing
          
                    [S] alt.rfc-writers.recovery RFC Writers Recovery
          
                    [S] tx.natives.recovery Texas Natives Recovery
          
                    [S] .
          
            Example of LIST NEWSGROUPS returning an error (e.g. The server
            software recognizes the command as valid, but the information
            is not available.)
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST NEWSGROUPS
          
                    [S] 503 program error, function not performed
          
          9.5 Standard extensions
          
            Each of the following sections describes an extension that a
            server MAY provide. If the server provides the extension, it
            MUST include the appropriate extension label in the response
            to LIST EXTENSIONS. If it does not provide it, it MUST NOT
            include the appropriate extension label. The descriptions of
            facilities in each section are written as if the extension is
          
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            provided. If it is not provided, the entire section should be
            ignored.
          
          
          9.5.1 LISTGROUP extension
          
            This extension provides one command and has the extension
            label LISTGROUP.
          
          9.5.1.1 The LISTGROUP Command
          
               LISTGROUP [ggg]
          
               The LISTGROUP command is used to get a listing of all the
               article numbers in a particular newsgroup.
          
               The optional parameter ggg is the name of the newsgroup to
               be selected (e.g. "news.software.b").  A list of valid
               newsgroups may be obtained from the LIST command. If no
               group is specified, the current group is used as the
               default argument.
          
               The successful selection response will be a list of the
               article numbers in the group followed by a period on a line
               by itself. The list starts on the next line following the
               211 response code.
          
               When a valid group is selected by means of this command,
               the internally maintained "current article pointer" MUST be
               set to the first article in the group and the name of the
               current newsgroup MUST be set to the selected newsgroup
               name. If an invalid group is specified, the previously
               selected group and article remain selected.  If an empty
               newsgroup is selected, the "current article pointer" may be
               in an indeterminate state and should not be used.
          
               The LISTGROUP keyword MAY be used by a client as a
               replacement for the GROUP command in establishing a valid
               "current article pointer." After a successful response is
               received, any other command may be used that depends on
               having the "current article pointer" be valid.
          
               The group name MUST match a newsgroup obtained from the
               LIST command or an error will result, else the server will
               respond with the 411 error code.
          
               A server that does not implement this command SHOULD return
               a 500 error response.
          
          
          9.5.1.1.1 Responses
          
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                 211 list of article numbers follow
          
                 411 No such group
          
                 412 Not currently in newsgroup
          
                 500 Command not recognized
          
          
          9.5.1.1.2 Examples
          
            Example of a successful execution with a group that exists on
            the server
          
                    [S] 200 NNTP Service Ready
          
                    [C] LISTGROUP misc.test
          
                    [S] 211 list of article numbers follow
          
                    [S] 3000234
          
                    [S] 3000237
          
                    [S] 3000238
          
                    [S] 3000239
          
                    [S] 3002322
          
                    [S] .
          
            Example of an unsuccessful execution with a group that does
            not exist on the server
          
                    [S] 200 NNTP Service Ready
          
                    [C] LISTGROUP this.group.is.not.here
          
                    [S] 411 no such group
          
            Example of an attempt to retrieve an article when the current
            group selected is empty
          
                    [S] 200 NNTP Service Ready
          
                    [C] LISTGROUP example.empty.newsgroup
          
                    [S] 412 No current article selected
          
          
          9.5.2 The OVER Extension
          
            This extension provides two commands, OVER and LIST
            OVERVIEW.FMT. The label for this extension is OVER.
          
          
          9.5.2.1 LIST OVERVIEW.FMT
          
            LIST OVERVIEW.FMT
          
          
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            The overview.fmt file is maintained by some news transport
            systems to contain the order in which header information is
            stored in the overview databases for each newsgroup.  When
            executed, news article header fields are displayed one line at
            a time in the order in which they are stored in the overview
            database[6] following the 215 response.  When display is
            completed, the server will send a period on a line by itself.
          
            If the information is not available, the server will return
            the 503 response.
          
            If the header has the word "full" (without quotes) after the
            colon, the header's name is prepended to its field in the
            output returned by the server.
          
            This is command is part of the optional OVER extension which
            includes the OVER command defined in section . If the OVER
            extension is not implemented, then this command MUST NOT be
            implemented. If that case, the server MUST return a 501 error
            response when this command is presented by the client.
          
          9.5.2.1.1 Responses
          
                 215 information follows
          
                 501 Syntax Error
          
                 503 program error, function not performed
          
          
          9.5.2.1.2 Examples
          
            Example of LIST OVERVIEW.FMT returning a list of newsgroups
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST OVERVIEW.FMT
          
                    [S] 215 Order of fields in overview database.
          
                    [S] Subject:
          
                    [S] From:
          
                    [S] Date:
          
                    [S] Message-ID:
          
                    [S] .
          
            Example of LIST OVERVIEW.FMT returning an error
          
                    [S] 200 NNTP Service Ready
          
                    [C] LIST OVERVIEW.FMT
          
                    [S] 503 program error, function not performed
          
          
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          9.5.2.2 OVER
          
            OVER [range]
          
            The OVER command returns specific header information for the
            article(s) specified from the current selected group. The
            information returned in the response to this command can be
            used by clients to follow discussion threads.
          
            The optional range argument may be any of the following:
          
               o an article number
          
               o an article number followed by a dash to indicate all
                 following
          
               o an article number followed by a dash followed by another
                 article number
          
            If no argument is specified, then information from the current
            article is displayed. Successful responses start with a 224
            response followed by the overview information for all matched
            messages. Once the output is complete, a period is sent on a
            line by itself. If no argument is specified, the information
            for the current article is returned.  A newsgroup must have
            been selected earlier, else a 412 error response is returned.
            If no articles are in the range specified, the server returns
            a 420 error response. A 502 response will be returned if the
            client only has permission to transfer articles. A 500
            response SHOULD be returned by servers do not implement this
            command.
          
            The output consists of one line per article, sorted in
            numerical order of article number. Each line consists of a
            number of fields separated by an US-ASCII TAB character. The
            first 8 fields MUST be the following, in order:
            article number, subject, author, date, message-ID, references,
            byte count, line count
          
            The content of any subsequent field is given by the response
            to the LIST OVERVIEW.FMT command. A field may be empty (in
            which case there will be two adjacent US-ASCII tabs, and a
            sequence of trailing US-ASCII tabs may be omitted). Any
            sequence of US-ASCII space or non-printing characters in a
            field MUST be replaced by a single US-ASCII space.
          
            The server SHOULD not produce output for articles that no
            longer exist.
          
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          INTERNET DRAFT                                          S. Barber
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          9.5.2.2.1 Responses
          
                 224 Overview information follows
          
                 412 No newsgroup current selected
          
                 420 No article(s) selected
          
                 500 Command not recognized
          
                 502 Service Unavailable
          
          
          9.5.2.2.2 Examples
          
            Example of a successful retrieval of overview information for
            an article (using no article number)
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] OVER
          
                    [S] 224 Overview information follows
          
                        300234|I am just a test article|nobody@nowhere.to
          
                        (Demo User)|6 Oct 1998 04:38:40 -0500|
          
                        <45223423@to.to>
          
                    [S] .
          
            [Please note that the line that begins with 300234 is all one
            line that has been wrapped for readability. A vertical bar has
            been inserted to show where the US-ASCII TAB should actually
            be.]
          
            Example of an unsuccessful retrieval of overview information
            on an article by number
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] OVER 300256
          
                    [S] 420 No such article in this group
          
            Example of an unsuccessful retrieval of overview information
            by number because no newsgroup was selected first
          
                    [S] 200 NNTP Service Ready
          
                    [C] OVER
          
                    [S] 412 No newsgroup selected
          
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          INTERNET DRAFT                                          S. Barber
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            Example of an attempt to retrieve an article when the current
            group selected is empty
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP example.empty.newsgroup
          
                    [S] 211 0 0 0 example.empty.newsgroup
          
                    [C] OVER
          
                    [S] 420 No current article selected
          
          
          9.5.3 The PAT Extension
          
            This extension provides one new command, PAT. The label for
            this extension is PAT.
          
          
          9.5.3.1 PAT
          
          
          
            PAT header range|<message-id> [wildmat]
          
            The PAT command is used to retrieve specific headers from
            specific articles in the currently selected group, based on
            pattern matching on the contents of the header.
          
            The required header parameter is the name of a header line
            (e.g.  "subject") in a newsgroup article. See RFC-1036 for a
            list of valid header lines. The required range argument may be
            any of the following:
          
               o an article number
          
               o an article number followed by a dash to indicate all
                 following
          
               o an article number followed by a dash followed by another
                 article number.
          
            The required message-id argument indicates a specific article.
            The range and message-id arguments are mutually exclusive.
            Additional arguments consisting of one or more wildmats,
            separated by an US-ASCII space, may be specified. The default
            is the single wildmat "*".
          
            A successful response consists of a 221 code followed by the
            output from the command. The output consists of one line for
            each article where the relevant header line matches one or
            more of the wildmats. The line consists of the article number,
            a US-ASCII space, and then the contents of the header (without
            the header name). A valid response includes an empty list
            (indicating that there were no matches). Once the output is
            complete, a period is sent on a line by itself. If the
          
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            optional argument is a message-id and no such article exists,
            a 430 error response shall be returned. A 502 response shall
            be returned if the client only has permission to transfer
            articles. A 500 response SHOULD be issued by all servers that
            do not recognize this command.
          
          9.5.3.1.1 Responses
          
                 221 Header follows
          
                 412 no newsgroup selected
          
                 430 no such article
          
                 500 Command not recognized
          
                 502 Service Unavailable
          
          
          9.5.3.1.2 Examples
          
            Example of a successful retrieval of subject lines from a
            range of articles
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] PAT Subject 3000234-300238
          
                    [S] 221 Header Follows
          
                    [S] 3000234 I am just a test article
          
                    [S] 3000237 Re: I am just a test article
          
                    [S] 3000238 Ditto
          
                    [S] .
          
            Example of a successful retrieval of subject lines from a
            range of articles with header pattern matching
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] PAT Subject 3000234-300238 *j*
          
                    [S] 221 Header Follows
          
                    [S] 3000234 I am just a test article
          
                    [S] 3000237 Re: I am just a test article
          
                    [S] .
          
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          INTERNET DRAFT                                          S. Barber
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            Example of a successful retrieval of header from an article by
            message-id
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP misc.test
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] PAT subject <i.am.a.test.article@nowhere.to>
          
                    [S] 221 Header information follows
          
                    [S] 3000345 I am just a test article
          
                    [S] .
          
            Example of an unsuccessful retrieval of a header from an
            article by message-id
          
                    [S] 200 NNTP Service Ready
          
                    [C] PAT subject <i.am.not.there@nowhere.to>
          
                    [S] 430 No Such Article Found
          
            Example of an unsuccessful retrieval of headers from articles
            by number because no newsgroup was selected first
          
                    [S] 200 NNTP Service Ready
          
                    [C] PAT subject 300256-
          
                    [S] 412 No newsgroup selected
          
            Example of an unsuccessful retrieval of headers from articles
            by message-id because no newsgroup was selected first
          
                    [S] 200 NNTP Service Ready
          
                    [C] PAT subject <i.am.a.test.article@nowhere.to>
          
                    [S] 412 No newsgroup selected
          
            Example of retrieving header information when the current
            group selected is empty
          
                    [S] 200 NNTP Service Ready
          
                    [C] GROUP example.empty.newsgroup
          
                    [S] 211 0 0 0 example.empty.newsgroup
          
                    [C] PAT subject 0-
          
                    [S] 221 Headers follow
          
                        .
          
            Example of a failure due to restrictions configured into the
            server
          
                    [S] 200 NNTP Service Ready
          
          
          
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          INTERNET DRAFT                                          S. Barber
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                    [C] GROUP news.group
          
                    [S] 211 1234 3000234 3002322 misc.test
          
                    [C] PAT Subject 3000234-300238
          
                    [S] 502 Service Unavailable
          
          
          10. The CONCLUSION Step
          
          
          10.1 QUIT
          
            QUIT
          
            The server process MUST acknowledge the QUIT command and then
            close the connection to the client.  This is the preferred
            method for a client to indicate that it has finished all its
            transactions with the NNTP server.
          
            If a client simply disconnects (or the connection times out or
            some other fault occurs), the server MUST gracefully cease its
            attempts to service the client, disconnecting from its end if
            necessary.
          
          
          10.1.1 Responses
          
                 205 closing connection - goodbye!
          
          
          10.1.2 Example
          
                    [S] 200 NNTP Service Ready
          
                    [C] QUIT
          
                    [S] 205 closing connection
          
          
          11. Other Keywords
          
            There are other keywords that may be used at any time between
            the beginning of a session and its termination.  Using these
            keywords does not alter any state information, but the
            response generated from the use of these keywords may provide
            useful information to clients that use them.
          
          
          11.1 DATE
          
            DATE
          
            This command exists to help clients find out the current time
            from the server's perspective.  This command SHOULD NOT be
          
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            used as a substitute for NTP[7], but to provide information
            that might be useful when using the NEWNEWS command (see
            section 11.4).
          
            This command returns a one-line response code of 111 followed
            by the UTC date and time on the server in the form
            YYYYMMDDhhmmss.
          
          
          11.1.1 Responses
          
                 111 YYYYMMDDhhmmss
          
          
          11.1.2 Example
          
                    [S] 200 NNTP Service Ready
          
                    [C] DATE
          
                    [S] 111 19990623135624
          
          
          11.2 The HELP Command
          
            HELP
          
            This command provides a short summary of commands that are
            understood by this implementation of the server. The help text
            will be presented as a textual response terminated by a single
            period on a line by itself.
          
            This text is not guaranteed to be in any particular format and
            SHALL NOT be used by clients as a replacement for the LIST
            EXTENSIONS command described in section 8.1.
          
          11.2.1 Responses
          
                 100 help text follows
          
          11.2.2 Example
          
                    [S] 200 NNTP Service Ready
          
                    [C] HELP
          
                    [S] 100 Help text follows
          
                    [S] This is some help text. There is no specific
          
                    [S] formatting requirement for this test, though
          
                    [S] it is customary for it to list the valid commands
          
                    [S] and give a brief definition of what they do
          
          
          
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                    [S] .
          
          
          11.3 NEWGROUPS
          
            NEWGROUPS date time [GMT|UTC]
          
            A list of newsgroups created since <date and time> MUST be
            listed in the same format as the LIST command.
          
            The date is sent as 6 or 8 digits in the format [XX]YYMMDD,
            where XX is the first two digits of the year, YY is the last
            two digits of the year, MM is the two digits of the month
            (with leading zero, if appropriate), and DD is the day of the
            month (with leading zero, if appropriate). If the first two
            digits of the year are not specified, the year is to be taken
            from the current century if YY is smaller than or equal to the
            current year, otherwise the year is from the previous century.
            Time must also be specified.  It must be as 6 digits HHMMSS
            with HH being hours in the 24-hour clock 00-23, MM minutes 00-
            59, and SS seconds 00-60, which allows for leap seconds. The
            tokens "GMT" and "UTC" specifies that the date and time are
            given in UTC. If the tokens "GMT" and "UTC" are omitted then
            the date and time are specified in the server's local
            timezone. Note that there is no way within this specification
            of NNTP to establish the server's local timezone.
          
            Note that an empty list (i.e., the text body returned by this
            command consists only of the terminating period) is a possible
            valid response, and indicates that there are currently no new
            newsgroups.
          
            Clients SHOULD make all queries using GMT/UTC time when
            possible.
          
          
          11.3.1 Responses
          
                 231 list of new newsgroups follows
          
          
          11.3.2 Examples
          
            Example where there are new groups
          
                    [S] 200 NNTP Service Ready
          
                    [C] NEWGROUPS 19990624 000000 UTC
          
                    [S] 230 list of new newsgroups follows
          
                    [S] alt.rfc-writers.recovery
          
                    [S] tx.natives.recovery
          
          
          
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          INTERNET DRAFT                                          S. Barber
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                    [S] .
          
            Example where there are no new groups
          
                    [S] 200 NNTP Service Ready
          
                    [C] NEWGROUPS 19990624 000000 UTC
          
                    [S] 230 list of new newsgroups follows
          
                    [S] .
          
          
          11.4 NEWNEWS
          
            NEWNEWS newsgroups date time [GMT|UTC]
          
            A list of message-ids of articles posted or received to the
            specified newsgroup or groups since "date" will be listed. The
            format of the listing will be one message-id per line, as
            though text were being sent. Each message-id SHALL appear only
            once in a response. The order of the response has no specific
            significance and may vary from response to response in the
            same session. A single line consisting solely of one period
            followed by CR-LF will terminate the list.
          
            Date and time are in the same format as the NEWGROUPS command.
            The newsgroups parameter MUST be in wildmat format and MAY
            consist of multiple wildmat constructs separated by an US-
            ASCII comma character.
          
            Note that an empty list (i.e., the text body returned by this
            command consists only of the terminating period) is a possible
            valid response, and indicates that there is currently no new
            news.
          
            Clients SHOULD make all queries in UTC time when possible.
          
          
          11.4.1 Responses
          
               230 list of new articles by message-id follows
          
          
          11.4.2 Examples
          
            Example where there are new articles
          
                    [S] 200 NNTP Service Ready
          
                    [C] NEWNEWS news.*,sci.* 19990624 000000
          
                    [S] 230 list of new articles by message-id follows
          
                    [S] <i.am.a.new.article@nowhere.to>
          
                    [S] <i.am.another.new.article@nowhere.to>
          
          
          
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          INTERNET DRAFT                                          S. Barber
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            Example where there are no new articles
          
                    [S] 200 NNTP Service Ready
          
                    [C] NEWNEWS alt.* 19990624 000000
          
                    [S] 230 list of new articles by message-id follows
          
                    [S] .
          
          
          12. Framework for NNTP Extensions
          
          
          
            Although NNTP is widely and robustly deployed, some parts of
            the Internet community might wish to extend the NNTP service.
            This memo defines a means whereby an extended NNTP client may
            query the server to determine the service extensions that it
            supports.
          
            It must be emphasized that any extension to the NNTP service
            should not be considered lightly. NNTP's strength comes
            primarily from its simplicity.  Experience with many protocols
            has shown that:
            Protocols with few options tend towards ubiquity, whilst
            protocols with many options tend towards obscurity.
          
            This means that each and every extension, regardless of its
            benefits, must be carefully scrutinized with respect to its
            implementation, deployment, and interoperability costs. In
            many cases, the cost of extending the NNTP service will likely
            outweigh the benefit.
          
            Given this environment, the framework for the extensions
            described in this memo consists of:
          
            a)a mechanism for clients to determine a server's available
                 extensions
          
            b)a registry of NNTP service extensions
          
            The LIST EXTENSIONS command is described in section 8.1 of
            this memo and is the mechanism for clients to use to determine
            what extensions are available for client use.
          
            The IANA shall maintain a registry of NNTP service extensions.
          
            An extension is identified by a unique extension-label, which
            is an string of 1 to 12 uppercase letters. The extension-label
            will often be the name of a new command that the extension
            adds. However this is not a requirement: an extension might
            not add any new commands or keywords.
          
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            An extension is either a private extension or else it is
            included in the IANA registry and is defined in an RFC. Such
            RFCs either must be on the standards-track or must define an
            IESG-approved experimental protocol.
          
            The definition of an extension must include:
          
               o a descriptive name for the extension
          
               o the extension-label (which is returned by LIST EXTENSIONS
                 to indicate to the client that the server supports this
                 particular extension)
          
               o the syntax, values, and meanings of any parameters
                 following the extension-label in the output of LIST
                 EXTENSIONS
          
               o any new NNTP keywords associated with the extension
          
               o the syntax and possible values of parameters associated
                 with the new NNTP keywords
          
               o any new parameters the extension associates with any
                 other pre-existing NNTP keywords
          
               o how support for the extension affects the behavior of a
                 server and client NNTP
          
               o any increase in the maximum length of commands over the
                 value specified in this memo
          
            The extension-label of private extensions MUST begin with "X".
            The extension-label of registered extensions MUST NOT begin
            with "X".
          
            Any keyword values presented in the NNTP response that do not
            begin with "X" MUST correspond to a standard, standards-track,
            or IESG-approved experimental NNTP service extension
            registered with IANA.  A conforming server MUST NOT offer non
            "X" prefixed keyword values that are not described in a
            registered extension.
          
            Except where stated otherwise, the commands in this document
            are understood (even if not supported) by all servers and are
            not described in the list of features returned by the LIST
            EXTENSIONS command.
          
            A server MAY provide additional keywords - either new commands
            or new parameters to existing commands - as part of a private
            extension. These new keywords MUST begin with "X".
          
            A server MUST NOT send different response codes to basic NNTP
            commands documented here or commands documented in registered
            extensions in response to the availability or use of a private
            extension.
          
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          12.1 Initial IANA Registry
          
            The IANA's initial registry of NNTP service extensions
            consists of these entries:
          
          Service Extension    NNTP Extension Label Added Behavior
          
          Overview Support     OVER               Defined in this
                                                     document
          
          Specific Article     LISTGROUP            Defined in this
          Numbers                                    document
          
          Header Pattern       PAT                  Defined in this
          Matching                                   document
          
          
          13. Augmented BNF[8] Syntax for NNTP Commands
          
          
          This syntax defines the non-terminal "command". The non-terminal
          "parameter" is used for command parameters whose syntax is
          specified elsewhere. The syntax is in alphabetical order. Note
          that ABNF strings are case insensitive.
          
            article-command = "ARTICLE" [1*WSP (msg-id / article-number)]
               *WSP CRLF
          
            article-number = 1*16DIGIT
          
            argument = parameter ; excluding sequence ".."
          
            body-command = "BODY" [1*WSP (msg-id / article-number)] *WSP
               CRLF
          
            command = article-command /
               body-command /
               date-command /
               group-command /
               head-command /
               help-command /
               ihave-command /
               last-command /
               list-active-times-command /
               list-distrib-pats-command /
               list-distributions-command /
               list-extensions-command /
               list-newsgroups-command /
               list-overview-fmt-command /
               list-command /
               listgroup-command /
               mode-reader-command /
               newgroups-command /
               newnews-command /
               next-command /
          
          
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               over-command /
               pat-command /
               post-command /
               quit-command /
               stat-command
          
            CR = %x0D
          
            CRLF = CR LF
          
            date-command = "DATE" *WSP CRLF
          
            date = 6*8DIGIT
          
            DIGIT = %x30-39
          
            group-command = "GROUP" 1*WSP newsgroup *WSP CRLF
          
            head-command = "HEAD" [1*WSP (msg-id / article-number)] *WSP
               CRLF
          
            header = parameter
          
            help-command = "HELP" *WSP CRLF
          
            HT = %x09
          
            ihave-command = "IHAVE" 1*WSP msg-id *WSP CRLF
          
            last-command = "LAST" *WSP CRLF
          
            LF = %x0A
          
            list-active-times-command = "LIST" 1*WSP "ACTIVE.TIMES"
               [1*WSP wildmat] *WSP CRLF
          
            list-command = "LIST" [1*WSP "ACTIVE" [1*WSP wildmat]] *WSP
               CRLF
          
            list-distrib-pats-command = "LIST" 1*WSP "DISTRIB.PATS" *WSP
               CRLF
          
            list-distributions-command = "LIST" 1*WSP "DISTRIBUTIONS" *WSP
               CRLF
          
            list-extensions-command = "LIST" 1*WSP "EXTENSIONS" *WSP CRLF
          
            list-newsgroups-command = "LIST" 1*WSP "NEWSGROUPS" [1*WSP
               wildmat] *WSP CRLF
          
            list-overview-fmt-command = "LIST" 1*WSP "OVERVIEW.FMT" *WSP
               CRLF
          
            listgroup-command = "LISTGROUP" [1*WSP newsgroup] *WSP CRLF
          
            mode-reader-command = "MODE" 1*WSP "READER" *WSP CRLF
          
            msg-id = <defined in RFC822>
          
            newgroups-command = "NEWGROUPS" 1*WSP date 1*WSP time [1*WSP
               "GMT"/"UTC"] *WSP CRLF
          
            newnews-command = "NEWNEWS" 1*WSP newsgroup *("," newsgroup)
               1*WSP date 1*WSP time [1*WSP "GMT"/"UTC"]
               *WSP CRLF
          
            newsgroup = parameter
          
            next-command = "NEXT" *WSP CRLF
          
            over-command = "OVER" [1*WSP range] *WSP CRLF
          
            parameter = 1*(%x21-FF) ; generic command parameter
          
            pat-command = "PAT" 1*WSP header 1*WSP (range / msg-id)
               *(1*WSP wildmat) *WSP CRLF
          
          
          
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                                                              November 2000
          
            post-command = "POST" *WSP CRLF
          
            quit-command = "QUIT" *WSP CRLF
          
            range = article-number ["-" [article-number]]
          
            SP = %x20
          
            stat-command = "STAT" [1*WSP (msg-id / article-number)] *WSP
               CRLF
          
            time = 6DIGIT
          
            UTF-8-non-ascii = UTF8-2 / UTF8-3 / UTF8-4 / UTF8-5 / UTF8-6
          
            UTF8-1 = %x80-BF
          
            UTF8-2 = %xC0-DF UTF8-1
          
            UTF8-3 = %xE0-EF 2UTF8-1
          
            UTF8-4 = %xF0-F7 3UTF8-1
          
            UTF8-5 = %xF8-FB 4UTF8-1
          
            UTF8-6 = %xFC-FD 5UTF8-1
          
            wildmat = ["!"]1*("*" / "?" / wildmat-exact / wildmat-set /
            "\" (%x22-7F / UTF-8-non-ascii))
          
            wildmat-exact = %x22-29 / %x2B-3E / %x40-5A / %x5D-7F / UTF-8-
               non-ascii ; exclude space ! * ? [ \
          
            wildmat-non-hyphen = %x21-2C / %x2E-7F / UTF-8-non-ascii ;
               exclude space -
            wildmat-set = "[" ["^"] ["]" / "-"] *(wildmat-non-hyphen"["-"
               wildmat-non-hyphen]) ["-"]
          
            WSP = SP / HT
          
          
          14. Security Considerations
          
            This section is meant to inform application developers,
            information providers, and users of the security limitations
            in NNTP as described by this document. The discussion does not
            include definitive solutions to the problems revealed, though
            it does make some suggestions for reducing security risks.
          
          
          14.1 Personal and Proprietary Information
          
            NNTP, because it was created to distribute network news
            articles, will forward whatever information is stored in those
            articles. Specification of that information is outside this
            scope of this document, but it is likely that some personal
            and/or proprietary information is available in some of those
            articles. It is very important that designers and implementers
            provide informative warnings to users so personal and/or
            proprietary information is not disclosed inadvertently.
          
            Additionally, effective and easily understood mechanisms to
            manage the distribution of news articles must be provided to
            NNTP Server administrators, so that they are able to report
            with confidence what information is and is not being forwarded
            in news articles passing though their servers.
          
          
          
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          14.2 Abuse of Server Log Information
          
            A server is in the position to save session data about a
            user's requests that might identify their reading patterns or
            subjects of interest. This information is clearly confidential
            in nature and its handling can be constrained by law in
            certain countries. People using the NNTP protocol to provide
            data are responsible for ensuring that such material is not
            distributed without the permission of any individuals that are
            identifiable by the published results.
          
          
          14.3 DNS Spoofing
          
            Clients and Servers using NNTP rely heavily on the Domain Name
            Service, and are thus generally prone to security attacks
            based on the deliberate misassociation of IP addresses and DNS
            names. Clients and Servers need to be cautious in assuming the
            continuing validity of an IP number/DNS name association.
            In particular, NNTP clients and servers SHOULD rely on their
            name resolver for confirmation of an IP number/DNS name
            association, rather than caching the result of previous host
            name lookups. Many platforms already can cache host name
            lookups locally when appropriate, and they SHOULD be
            configured to do so. It is proper for these lookups to be
            cached, however, only when the TTL (Time To Live) information
            reported by the name server makes it likely that the cached
            information will remain useful.
          
            If NNTP clients or servers cache the results of host name
            lookups in order to achieve a performance improvement, they
            MUST observe the TTL information reported by DNS.
          
            If NNTP clients or servers do not observe this rule, they
            could be spoofed when a previously-accessed server's IP
            address changes. As network renumbering is expected to become
            increasingly common, the possibility of this form of attack
            will grow. Observing this requirement thus reduces this
            potential security vulnerability.
          
            This requirement also improves the load-balancing behavior of
            clients for replicated servers using the same DNS name and
            reduces the likelihood of a user's experiencing failure in
            accessing sites which use that strategy.
          
          
          
          
          Barber                                             [Page 58]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
          14.4 Weak Authentication and Access Control
          
            There is no user-based or token-based authentication in the
            basic NNTP specification. Access is normally controlled by
            server configuration files. Those files specify access by
            using domain names or IP addresses. However, this
            specification does permit the creation of extensions to the
            NNTP protocol itself for such purposes. While including such
            mechanisms is optional, doing so is strongly encouraged.
            Other mechanisms are also available. For example, a proxy
            server could be put in place that requires authentication
            before connecting via the proxy to the NNTP server.
          
          15. References
          
            [1] Kantor, B and P. Lapsley, "Network News Transfer Protocol",
            RFC-977, U.C. San Diego and U.C. Berkeley.
          
            [2] Yergeau, F., "UTF-8, a transformation format of ISO 10646",
            RFC 2279, Alis Technologies.
          
            [3] Coded Character Set-7-bit American Standard Code for
            Information Interchange, ANSI x3.4-1986.
          
            [4] Bradner, Scott, "Key words for use in RFCs to Indicate
            Requirement Levels", RFC-2119, Harvard University.
          
            [5] Salz, Rich, Manual Page for wildmat(3) from the INN 1.4
            distribution, UUNET Technologies, Revision 1.10, April, 1992.
          
            [6]  Robertson, Rob, "FAQ: Overview database / NOV General
            Information", ftp://ftp.uu.net/networking/news/nntp/inn/faq-
            nov.Z, January, 1995.
          
            [7] Mills, David L., "Network Time Protocol (Version 3),
            Specification, Implementation and Analysis", RFC-1305,
            University of Delaware, March 1992.
          
            [8] Crocker, D.  and Overell, P., "Augmented BNF for Syntax
            Specifications: ABNF", RFC-2234, Internet Mail Consortium and
            Demon Internet, Ltd.
          
          16. Notes
          
            UNIX is a registered trademark of the X/Open Consortium.
          
          Barber                                             [Page 59]
          

          INTERNET DRAFT                                          S. Barber
          Expires: June 30, 2001                 Academ Consulting Services
                                                              November 2000
          
          17. Acknowledgments
          
            The author acknowledges the original authors of NNTP as
            documented in RFC 977: Brian Kantor and Phil Lapsey.
            The author gratefully acknowledges the work of the NNTP
            committee chaired by Eliot Lear. The organization of this
            document was influenced by the last available draft from this
            working group. A special thanks to Eliot for generously
            providing the original machine readable sources for that
            document.
          
            The author gratefully acknowledges the work of the Marshall
            Rose & John G. Meyers in RFC 1939 and the work of the DRUMS
            working group, specifically RFC 1869, which is the basis of
            the NNTP extensions mechanism detailed in this document.
            The author gratefully acknowledges the authors of RFC 2616 for
            providing specific and relevant examples of security issues
            that should be considered for HTTP. Since many of the same
            considerations exist for NNTP, those examples that are
            relevant have been included here with some minor rewrites.
          
            The author gratefully acknowledges the comments and additional
            information provided by the following individuals in preparing
            one of the progenitors of this document:
          
               o Wayne Davison <davison@armory.com>
          
               o Clive D.W. Feather <clive@demon.net>
          
               o Chris Lewis <clewis@bnr.ca>
          
               o Tom Limoncelli <tal@mars.superlink.net>
          
               o Eric Schnoebelen <eric@egsner.cirr.com>
          
               o Rich Salz <rsalz@osf.org>
          
            This work was motivated by the work of various newsreader
            authors and newsserver authors, which includes those listed
            below:
          
               o Rick Adams-Original author of the NNTP extensions to the
                 RN newsreader and last maintainer of Bnews
          
               o Stan Barber-Original author of the NNTP extensions to the
                 newsreaders that are part of Bnews.
          
               o Geoff Collyer-Original author of the OVERVIEW database
                 proposal and one of the original authors of CNEWS
          
               o Dan Curry-Original author of the xvnews newsreader
          
               o Wayne Davison-Author of the first threading extensions to
                 the RN newsreader (commonly called TRN).
          
               o Geoff Huston-Original author of ANU NEWS
          
               o Phil Lapsey-Original author of the UNIX reference
                 implementation for NNTP
          
               o Iain Lea-Original maintainer of the TIN newsreader
          
               o Chris Lewis-First known implementor of the AUTHINFO
                 GENERIC extension
          
               o Rich Salz-Original author of INN
          
               o Henry Spencer-One of the original authors of CNEWS
          
               o Kim Storm-Original author of the NN newsreader
          
          
          18.Author's Address
          
            Stan Barber
            P.O. Box 300481
            Houston, Texas 77230
            Email: <sob@academ.com>
          
            This document expires June 30, 2001.
          
          Barber                                             [Page 60]
          

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