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INTERNET-DRAFT                                                   P. Grau
<draft-dfncis-netnews-admin-sys-01.txt>                        V. Heinau
Expires November 27, 2000                                 H. Schlichting
                                                                 DFN-CIS
                                                                May 2000


                  Netnews Administration System (NAS)
                <draft-dfncis-netnews-admin-sys-01.txt>



Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of section 10 of [RFC2026].

   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 obsoleted 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 accessed 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.


Abstract

   The Netnews Administration System (NAS) is a framework to simplify
   the administration and usage of network news on the Internet. Data
   for the administration of newsgroups and hierarchies are kept in a
   distributed hierarchical database, and are available through a
   client-server-protocol.

   The database is accessible by news servers and news administrators as
   well as by news readers. News servers can update their configuration
   automatically, administrators are able to get the data manually. News
   reader programs are able to get certain information from an NAS
   server, automatically or at a user's discretion, to provide detailed
   information about groups and hierarchies to the user.




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   NAS is usable in coexistence with the current, established process of
   control messages, an unwanted interference is impossible.
   Furthermore, NAS is able to reflect the somewhat chaotic structure of
   Usenet in a hierarchical database. NAS can be used without
   modification of existing news relay, news server or news reader
   software, however some tasks will be better accomplished with NAS
   compliant software.












































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                           Table of Contents

Status of this Memo ...............................................    1
Abstract ..........................................................    1
1.  Introduction ..................................................    4
2.  Overview ......................................................    5
3.  Protocol Level ................................................    6
4.  Description of Functions ......................................    7
5.  Definitions ...................................................    8
6.  Specification of the NAS Protocol (TCP) .......................    8
    6.1.  Responses ...............................................    8
        6.1.1.  Overview ..........................................    8
        6.1.2.  Response Code Values, Structure and Meaning .......    9
    6.2.  Connection setup ........................................   10
    6.3.  Commands ................................................   10
        6.3.1.  Structure .........................................   10
        6.3.2.  Overview ..........................................   11
        6.3.3.  Detailed Description ..............................   11
            6.3.3.1.  HELP ........................................   11
            6.3.3.2.  INFO ........................................   13
            6.3.3.3.  DATE ........................................   14
            6.3.3.4.  VERS ........................................   15
            6.3.3.5.  QUIT ........................................   16
            6.3.3.6.  LIST ........................................   16
            6.3.3.7.  LSTR ........................................   18
            6.3.3.8.  HIER ........................................   20
            6.3.3.9.  DATA ........................................   21
            6.3.3.10.  GETL .......................................   23
            6.3.3.11.  GETP .......................................   24
            6.3.3.12.  GETA .......................................   27
            6.3.3.13.  Unknown Commands and Syntax Errors .........   29
        6.3.4.  Data Headers ......................................   29
    6.4.  Status Indicators .......................................   41
    6.5.  Newsgroup Types .........................................   41
    6.6.  Hierarchy Types .........................................   42
    6.7.  PGP Keys ................................................   42
7.  Specification of the NAS Protocol (UDP) .......................   43
8.  Security Considerations .......................................   44
9.  References ....................................................   44
10.  Author's Address .............................................   45
Appendix A - Response Codes (Overview) ............................   45
Appendix B - Data Header for DATA and HIER Commands (Overview)









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1.  Introduction

   The increasing number of newsgroups, hierarchies and articles has
   made the administration of news servers a complex and time consuming
   task. The tools for the administration are unchanged for nearly ten
   years now and no longer appropriate. Many hierarchies are
   inconsistent, many new newsgroups are not created or only with a huge
   delay, removed groups keep lurking in the configuration files for a
   long period of time. There is no administration tool that utilizes
   the power of the Internet, nor is there a possibility to check the
   consistency of the news server at a given point of time.

   Users have difficulties to get an overview of the newsgroups, the
   charter of a particular one, which language is preferred, or whether
   a group is moderated or not. Renaming, the status change from
   moderated to unmoderated or vice versa, the splitting of a group into
   several others are dynamic processes. These processes are common use,
   but it takes a long time until every news server is aware of these
   changes.

   An increasing number of faked control messages appeared in the last
   few years. Purposely or accidentally control messages were sent to
   foreign news servers to create or remove a certain group, although
   this task was not approved by the rules of the hierarchy in question.
   Due to this fact, on many news servers the automatic creation is
   disabled and several dead groups have not been deleted. It is very
   difficult for users to determine the status of a group, and therefore
   the propagation of articles is affected by this fact.

   It is the design goal of NAS to provide a out of band system that
   helps to maintain, propagate and deliver the required information.
   There will not be any interference with current protocols and
   standards. It is not intended to make use of control messages or some
   special nntp commands. The advantage of NAS is that it provides more
   information in a more structured format than control messages. Not
   only news server administrators but also Usenet users can get more
   detailed information about newsgroups and hierarchies.

   Due to the fact that a client connects to a server, and the server
   asks for authentication, this is is a more resonable procedure of
   transmitting information than control messages. Futhermore it is
   possible to check for changes on a regular basis at customized
   intervals to keep local data uptodate.








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2.  Overview

   NAS is based on a database which contains information belonging to
   certain groups and hierarchies. This database is structured in a
   hierarchical manner, distributed to various servers and is able to
   receive queries at any time. The service is comparable to directory
   services like DNS, LDAP or NIS. The NAS protocol is inspired by
   protocols like NNTP and SMTP.  There already is a reserved port
   number for NAS, 991. It is registered by the Internet Assigned Number
   Authority (IANA) [IANA-PN].

   The organizational structure of NAS is hierarchical, that means an
   NAS root server collects data from the subservers which are
   authoritative for certain hierarchies. The root server signs the data
   and distributes it authoritatively. Replication of database entries
   is possible. The hierarchical structure can consist of multiple
   levels. Usage of the database is possible for news servers, news
   readers and special client programs. The communication is based on
   TCP and UDP.

   Taking the real world in account, there migth be some policy problems
   with a single root server. But it is possible to establish a
   structure like the current Usenet system, where some hierarchies have
   a good administration with a well defined system of rules and some
   which are not well maintained. The goal is to get as much information
   as possible under one hat, but there can be no "official" force to
   achieve this.

   During the startup phase it's quite likely that there will be a root
   server, handling just hierarchies with strict rules and accepted
   authorities (like BIG8, de.*, us.*, bln.*, fr.*, it.*, etc.).

   However it is also imaginable to have some NAS servers providing data
   on - for exapmle - alt.!binaries, some providing data on alt.*, and
   even some providing alt.*  following special policies or sets of
   rules.

   An administrator using NAS will have the choice to use just one root
   server (and all its data) and/or to use another NAS server for
   special hierarchies.

    ..............   ..............     ...................
    . NAS server .   . NAS server .     . NAS server      .
    .            .   .            .     . alt.*,          .
    . alt.*      .   . Big8       .     . !alt.binaries.* .
    ..............   ..............     ...................
    . database   .   . database   .     . database        .
    ..............   ..............     ...................



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           ^            ^      ^                  ^
           `--+      +--'      `------+      +----'
              |      |                |      |
           .------------.          .------------.
           | NAS client |          | NAS client |
           +------------+          +------------+
           |  netnews   |          |  netnews   |
           |  server    |          |  server    |
           .------------.          .------------.

           Configuration A         Configuration B

   NAS contains information about newsgroups as well as complete
   hierarchies. Furthermore it contains the information about the
   hierarchies' inheritable entries and default values for a single
   newsgroup.


3.  Protocol Level

   It is expected that the real life use of NAS will change the
   requirements for the Netnews Administration System. On one hand the
   protocol has to be extensible and flexible in order to implement
   improvements. On the other hand it must ensure compatibility between
   different versions. A simultaneous migration of all sites using NAS
   to a new protocol version is not likely to happen. To solve this
   problem, NAS has got a protocol level defined. This protocol level
   describes the current functionality. The protocol level, being a
   number between 1 and 32767, is negotiated at connection setup.
   Enhancements and modifications must use a different protocol level
   than their predecessors. (Usually the protocol level is incremented
   by 1 with every new version of the protocol specification.) Every
   current or future implementation must be compatible with the protocol
   level 1, in order to fall back to this level when communication on a
   higher level fails.

   An implementation of higher protocol levels should be able to emulate
   the behavior of lower levels, even if this implies a loss of
   features. The negotiation of the protocol level between client and
   server is described in the specification of the command VERS. If
   there is no agreement on the protocol level, only commands of the
   protocol level 1 must be used. Documents enhancing or modifying the
   NAS standard must specify from upon which level these changes take
   place and how the behavior should be in other protocol levels.

   This document describes protocol level 1.





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4.  Description of Functions

   In order to use an NAS server, a connection must be opened by the
   client. The NAS server can be located in the same domain or somewhere
   else on the Internet.

   The NAS system is hierarchical. The idea is to have an NAS root
   server like the DNS root servers.  The root server distributes the
   data collected from client NAS servers, which are authoritative
   servers for their hierarchy.  The maintenance of the authoritative
   data is possible on any system. The root server collects the data and
   makes them available to other servers, which also can distribute
   these data to other servers. The administrator has the opportunity to
   make use of either all data or only parts of the database. NAS
   servers can ask multiple NAS servers for data. An attached time stamp
   provides the possibility to distinguish between new and old data, and
   to avoid loops in the propagation.

   To describe the NAS in greater detail it is necessary to emphasize
   the hierarchical design of the NAS system.  The following picture
   shows the propagation of data along the server hierarchy. There are
   two kinds of data collection: In first place the authoritative data
   for a newsgroup or a hierarchy are collected, and written into a
   database. This database is made available to a local NAS server. The
   data will then be collected by the upstream NAS server.

    ............     collects from >
    . root NAS .-------------------------+
    . server   .----------------+        |
    ............                |        |
    . database .                |        |
    ............                |        |
          ^ v                   |    ..............
          | |                   |    . de.*       .
          | |distributes        |    . NAS server .
   queries| |                   |    ..............
          | |                   |    .  database  .
          ^ v                   |    ..............
    ............                |
    . database .                `--------+
    . with NAS .                         |
    . client   .                     ..............
    ............                     . bln.*      .
      ^  ^  ^                        . NAS server .
      |  |  |  .---------.           ..............
    q |  |  `--| netnews |           .  database  .
    u |  |     | server  |           ..............
    e |  |     .---------.



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    r |  |
    i |  |  .---------.
    e |  `--| admin   |
    s |     | program |
      |     .---------.
      |
      |  .---------.
      `--| news    |
         | reader  |
         .---------.

   Requests to an NAS server originating at a client as well as
   another server are accomplished in several steps, as there are:
   Establishing a connection, authentication (optional),
   negotiating a protocol level (optional), queries on
   the database, and termination.


5.  Definitions

   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 [RFC2119].


6.  Specification of the NAS Protocol (TCP)

6.1.  Responses

6.1.1.  Overview


   An answer will start with a response code (a three digit number),
   optionally followed by white space and a textual message. Then the
   actual Text/Data will follow. Text is send as a series of successive
   lines of textual matter, each terminated with CRLF. A single line
   containing only a single period ('.') is sent to indicate the end of
   the text (i.e. the server will send a CRLF at the end of the last
   line of text, a period, and another CRLF).

   Answer = Status [ WSP Text] CRLF
            Data CRLF;
            "." CRLF

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



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   doubled period to a single one.

   Example:

   <-- INFO
   --> 101 Information follows
       Server: nas.fu-berlin.de (160.45.11.141)
       Uptime: 2 weeks, 3 days, 5 hours, 9 minutes
       Software: NAS 1.0
       Client: waran.cis.fu-berlin.de (160.45.11.136)
       Connection: 9 minutes
       Highest protocol level supported: 1
       Requested protocol level: 1
       Protocol level used: 1
       .


6.1.2.  Response Code Values, Structure and Meaning

   The first digit of the response code indicates the message type, i.e.
   informational, success, warning, error, data:

   1xx Information
   2xx Request successful
   3xx Request successful, data follow
   4xx Request accepted, but no operation possible
   5xx Request is wrong (syntax error), not implemented, or leads to an
       internal error
   6xx Request successful, data follow until end mark

   The second digit specifies the message category:

   x0x connection related stuff
   x1x queries, answers, data
   x2x server-server communication
   x3x authentication, authorization
   x8x non-standard extensions
   x9x debugging output

   The actual response code for a specific command is listed in the
   description of the commands. Answers of the type 1xx, 2xx, 4xx, and
   5xx can have a text after the numerical code. 3xx answers contain one
   or more parameters with data, the exact format is explained in the
   description of the commands.

   An answer to an incorrect request may be longer than one line.





Grau, Heinau, Schlichting                                       [Page 9]


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6.2.  Connection setup

   NAS typically uses port 991, which is reserved by IANA [IANA-PN].  If
   a connection is set up by the client, the server answers immediately
   (without a request) with the greeting message, which will start with
   code 200:

   --> 200 Welcome!
       nas.fu-berlin.de ready
       .

   If a connection is refused because the client has no permission
   to access the server, the answer code is 434. When the server
   is currently out of service, the answer code is 404.

    Examples:

   434 You have no permission to retrieve data. Good bye.
   404 Maintenance time

   After sending a 404 or 434 message the connection will be closed.


6.3.  Commands

6.3.1.  Structure

   A command consists of a command word, sometimes followed by a
   parameter. Parameters are separated from the command word by white
   space.

   Commands used in the NAS protocol are not case sensitive. A command
   word or parameter may be upper case, lower case, or any mixture of
   upper and lower case.

   The length of a command line is not limited.

   The protocol level described in this document uses command words with
   a length of exactly four characters each.

   In examples, octets sent to the NAS server are preceded by "<-- " and
   those sent by the NAS server by "--> ". The indicator is omitted if
   the direction of the dialog does not change.








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6.3.2.  Overview

   The commands described below are defined using the Augmented Backus-
   Naur Form (ABNF) defined in [RFC2234]. The definitions for `ALPHA',
   `CRLF', `DIGIT', `WSP' and `VCHAR' are taken from appendix A of
   [RFC2234] and not repeated here.

   The following ABNF definitions comprise the set of NAS commands which
   can be sent from the client to an NAS server.

6.3.3.  Detailed Description

   Some overall definitions:

   text       = %d1-9 /           ; all octets except
                %d11-12 /         ; US-ASCII NUL, CR and LF
                %d14-255

   answertext = WSP *(ALPHA / DIGIT / "+"/ "-"/ "/"/ "_"/ "="/ "?"/ "!"/ SP)

   utc-time   = 14*DIGIT  ; The date and time of the server in UTC
                          ; YYYYMMDDhhmmss

   Newsgroup names and hierarchy names are defined according to the
   following ABNF definitions. Since a hierarchy name can be the same as
   a newsgroup name (e.g., hierarchy bln.announce.fub.* and newsgroup
   name bln.announce.fub) there is no difference between the two.

   hierarchy-name      =  newsgroup-name ; these two are identical
   newsgroup-name      =  plain-component *( "." component )
   component           =  plain-component / encoded-word
   encoded-word        =  lowercase / DIGIT
                       =/ "+"/ "-"/ "/"/ "_"/ "="/ "?"
   plain-component     =  first-component-start component-rest
   first-component-start = lowercase
   component-start     =  lowercase / digit
   lowercase           =  %x61-7a ; letter a-z lowercase
   component-rest      =  component-start / "+"/ "-"/ "_"

NOTE: This definition of a newsgroup name is according to
son-of-1036-draft [SON1036]. When the current draft "News Article
Format" [USRFOR] is established as an RFC, it's definitions should be
integrated into a higher protocol level of NAS.

6.3.3.1.  HELP

   Description




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   This command prints a short help text on a given command.  If called
   without parameters it will display a complete list of commands.

   help-cmd = "HELP" [ WSP Commandname ] CRLF

   Commandname =  "DATA" / "DATE" / "GETL" / "GETP" / "GETA"
               =/ "HELP" / "HIER" / "INFO" / "LIST" / "LSTR"
               =/ "QUIT" / "VERS"

   Possible answers

   100: Command overview, command description
   410: Indicates that the server is not giving any information


   help-answer =  "410" [ answertext ] CRLF
                  text CRLF
                  "." CRLF
               =/ "100" [ answertext ] CRLF
                  text CRLF
                  "." CRLF

   Examples

   <-- HELP
   --> 100 NAS server nas.fu-berlin.de, Version 1.0

       Supported commands:
       DATA - data for a newsgroup
       DATE - show time of server in UTC
       GETL - get list of hierarchy packages
       GETP - get package
       GETA - get data from an authoritative server
       HELP - show this help
       HIER - data for a hierarchy
       INFO - show info on current connection
       LIST - list newsgroups or hierarchies
       LSTR - recursive list newsgroups or hierarchies
       QUIT - close the connection
       VERS - show or set current protocol level

       Contact address nas@cis.fu-berlin.de
       .

   <-- HELP LIST
   --> 100 LIST
       LIST - list newsgroups or hierarchies
       Syntax: LIST hierarchy ...



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       Get a list of newsgroups and sub-hierarchies
       directly under the parameter hierarchy
       .

   <-- HELP NOOP
   --> 410
       unknown command "NOOP"
       .


6.3.3.2.  INFO

   Description

   Prints information about the current connection, the server, and the
   client.

   info-cmd =  "INFO" CRLF

   Possible answers

   101: Normal answer, prints some information about client
        and server
   400: Indicates that the server is not giving any information


   info-answer =  "400" [ answertext ] CRLF
                  text CRLF
                  "." CRLF
               =/ "101" [ answertext ] CRLF
                  text CRLF
                  "." CRLF

   Examples

   <-- INFO
   --> 101 Information follows
       Server: nas.fu-berlin.de (160.45.11.141)
       Uptime: 2 weeks, 3 days, 5 hours, 9 minutes
       Software: NAS 1.0
       Client: waran.cis.fu-berlin.de (160.45.11.136)
       Connection: 9 minutes
       Highest protocol level supported: 1
       Requested protocol level: 1
       Protocol level used: 1

       End
       .



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   <-- INFO
   --> 400
       No information available.
       .



6.3.3.3.  DATE

   Description

   Prints the actual time of the server in UTC (Universal Coordinated
   Time) in the format YYYYMMDDhhmmss, followed by an optional comment.
   The DATE command is only for informational use and to control the
   server time. For regular transmission of time over the network the
   NTP protocol [RFC1305] should be used.

   date-cmd =  "DATE" CRLF

   Possible answers

   300: Print the UTC time in specified format, see below
   511: Error, print an error message

   date-answer =  "511" [ answertext ] CRLF
                  text CRLF
                  "." CRLF
               =/ "300" [ answertext ] CRLF
                  utc-time [ answertext ] CRLF
                  "." CRLF



   Examples

   <-- DATE
   --> 300
       19990427135230 UTC
       .

   <-- DATE
   --> 511
       Time is unknown
       .







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6.3.3.4.  VERS

   Description

   The VERS command is used to determine the protocol level used between
   client and server. The parameter is a protocol level which the client
   supports and wants to use. The server will respond with the highest
   level that will be accepted. That version number must not be higher
   than requested by the client. Client and server must only use
   commands from the level that the server has confirmed. It is
   possible, but seldom necessary, to change the protocol level during a
   session by client request (VERS [protocol level]). When no option is
   given, the current protocol level will be printed. When no protocol
   level is negotiated, the protocol level 1 will be used. Commands of a
   higher level are not allowed without a successful negotiation. The
   protocol level can be followed by an optional comment.

   vers-cmd =  "VERS" [ WSP level ] CRLF

   level = 1*5DIGIT ; the valid range is 1 - 32767

   Possible answers

   202: Returns current protocol level
   302: Answer to an successful request
   402: Requested level too high, falling back to lower level
   510: Syntax error


   vers-answer =  "202" [ answertext ] CRLF
                  level [ answertext ] CRLF
                  "." CRLF
               =/ "302" [ answertext ] CRLF
                  level [ answertext ] WSP level CRLF
                  "." CRLF
               =/ "402" [ answertext ] CRLF
                  level [ answertext ] WSP level CRLF
                  "." CRLF
               =/ "510" [ answertext ] CRLF
                  level [ answertext ] CRLF
                  "." CRLF

   Examples

   <-- VERS
   --> 202
       2 Current protocol level is 2
       .



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   <-- VERS 2
   --> 302
       2 My max protocol level is 10
       .

   <-- VERS 11
   --> 402
       10 Falling back to level 10
       .

   <-- VERS BAL
   --> 510
       1 Syntax error
       .


6.3.3.5.  QUIT

   Description

   Terminates the connection.

   quit-cmd =  "QUIT" CRLF

   Possible answers

   201: Termination of the connection

   quit-answer = "201" [ answertext ] CRLF


   Examples

   <-- QUIT
   --> 201 Closing connection. Bye.



6.3.3.6.  LIST

   Description

   To obtain a list of newsgroups and sub-hierarchies in the requested
   hierarchies the command LIST is used. The status of the hierarchies
   is also given. The highest level consists of all top-level
   hierarchies and is labeled "*". It can be obtained this way, too.

   After the response code 610 follow white space and the end mark. The



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   last line of the data stream must begin with the end mark. The end
   mark will be checked case insensitive. Comments after the separating
   white space are allowed.

   The data consist of a newsgroup- or hierarchy-name/status indicator
   pair per line. Name and status indicator must be separated by at
   least one white space. The status indicator is one letter (see
   section 6.3.5). The interpretation is not case sensitive.

   list-cmd =  "LIST" ( "*" | 1*(WSP hierarchy-name)) CRLF

   Possible answers

   401: Permission denied
   530: The parameter "hierarchy" is missing
   610: Regular answer with all requested data

   list-answer =  "610" [ answertext ] CRLF
                  *( listdata CRLF )
                  "." CRLF
               =/ "401" [ WSP text ] CRLF
                  text CRLF
                  "." CRLF
               =/ "530" [ WSP text ] CRLF
                   text CRLF
                   "." CRLF

   listdata    =  newsgroup-name WSP list-status CRLF

   The list-status is the status of a newsgroup or hierarchy according
   to section 6.4.

   list-status =  "Hierarchy-Complete"
               =/ "Hierarchy-Incomplete"
               =/ "Hierarchy-Obsolete"
               =/ "Hierarchy-Unkown"
               =/ "Group-Post-Yes"
               =/ "Group-Post-No"
               =/ "Group-Moderated"
               =/ "Group-Removed"
               =/ "Group-Unkown"
               ; list-status is case-insensitive

   Examples

   <-- LIST *
   --> 610 data follow
       alt Hierarchy-Incomplete



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       bln Hierarchy-Complete
       comp Hierarchy-Complete
       de Hierarchy-Complete
       rec Hierarchy-Complete
       sub Hierarchy-Obsolete
       .

   <-- LIST de
   --> 610 data follow
       de.admin Hierarchy-Complete
       de.alt Hierarchy-Incomplete
       de.comm Hierarchy-Complete
       de.comp Hierarchy-Complete
       de.etc Hierarchy-Complete
       de.markt Hierarchy-Complete
       de.newusers Hierarchy-Complete
       de.org Hierarchy-Complete
       de.rec Hierarchy-Complete
       de.sci Hierarchy-Complete
       de.soc Hierarchy-Complete
       de.talk Hierarchy-Complete
       de.answers Group-Moderated
       de.test Group-Post-Yes
       .

   <-- LIST foo
   --> 610 data follow
       foo Hierarchy-Unkown
       .

   <-- LIST
   --> 530
       missing parameter hierarchy
       .

   <-- LIST de
   --> 401 Some thing is wrong
       Permission denied
       .


6.3.3.7.  LSTR

   Description

   To obtain a recursive list of newsgroups and sub-hierarchies in the
   named hierarchy the command LSTR is used. The status of the
   hierarchies is also given. The highest level consists of all top-



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   level hierarchies and is labeled "*". It can be obtained this way,
   too.

   The use of wildmat patters is also possible, so a "LSTR de.a*" would
   return a list of all newsgroup starting with de.a*.

Note: This is according to wildmat(3) from libinn, it SHOULD be possible
to issue requests in the style of the newsfeeds(5) pattern for newsgroup
syntax.

   lstr-cmd = "LSTR" ( "*" | 1*(WSP hierarchy-name)) CRLF

   Possible answers

   401: Permission denied
   530: The parameter "hierarchy" is missing
   610: Regular answer with all requested data

   lstr-answer =  "610" [ answertext ] CRLF
                  *( listdata CRLF )
                  "." CRLF
               =/ "401" [ answertext ] CRLF
                  text CRLF
                  "." CRLF
               =/ "530" [ answertext ] CRLF
                  text CRLF
                  "." CRLF

   listdata    =  newsgroup-name WSP list-status CRLF

   Examples

   <-- LSTR de.admin
   --> 610 recursive mode
       de.admin Hierarchy-Complete
       de.admin.archiv Group-Post-Yes
       de.admin.infos Group-Moderated
       de.admin.lists Group-Moderated
       de.admin.misc Group-Post-Yes
       de.admin.net-abuse Hierarchy-Complete
       de.admin.net-abuse.announce Moderated
       de.admin.net-abuse.mail Group-Post-Yes
       de.admin.net-abuse.misc Group-Post-Yes
       de.admin.net-abuse.news Group-Post-Yes
       de.admin.news Hierarchy-Complete
       de.admin.news.announce Group-Moderated
       de.admin.news.groups Group-Post-Yes
       de.admin.news.misc Group-Post-Yes



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       de.admin.news.nocem Group-Post-Yes
       de.admin.news.regeln Group-Post-Yes
       de.admin.submaps Group-Moderated
       .


6.3.3.8.  HIER

   Description

   The command HIER lists all available information about the hierarchy.
   With data header "Name" a new data block for each hierarchy is
   started. Code "Name" gives the name of the hierarchy. The data
   headers are described in section 6.3.4. The default is to transmit
   all aviable information. It can be limited to a list of desired
   headers ("Name" and "Status" are allways given). A set of comma
   separated headers as a option to the HIER command will return the
   requested header fields.

   hier-cmd =  "HIER" [ WSP range ] 1*( WSP hierarchy-name) CRLF

   range    = *( header ",") header ; Describes the data fields
                                    ; that are requested
   header   = *( ALPHA / "-") ; According to section 6.3.4

   Examples for range:

   Followup,Description : for all entries list Name, Status, Followup
                          and Description

   Possible answers

   401: Permission denied
   530: Missing parameter
   611: Regular answer with all requested data

   hier-answer =  "611" [ answertext ] CRLF
                  *( hierdata CRLF )
                  "." CRLF
               =/ "530" [ answertext ] CRLF
                  *( text CRLF )
                  "." CRLF
               =/ "401" [ answertext ] CRLF
                  *( text CRLF )
                  "." CRLF

   hierdata    =  "Name:" WSP test CRLF
                  "Status:" WSP text CRLF



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                  *( header ":" WSP text CRLF )
                  ( "Ctl-PGP-Key:" CRLF PGP-answer )
                  ( "Mod-PGP-Key:" CRLF PGP-answer )

   PGP-answer: The exact format is described in section 6.7

   Examples

   <-- HIER de
   --> 611 Data coming
       Name: de
       Status: Hierarchy-Complete
       Description: Internationale deutschsprachige Newsgruppen
       Netiquette: http://www.dana.de/de/netiquette.html
       Faq: http://www.dana.de/de/neue-de-gruppe.html
       Ctl-Send-Adr: moderator@dana.de
       Ctl-Newsgroup: de.admin.news.announce
       Mod-Wildcard: %s@moderators.dana.de
       Language: DE
       Charset: ISO-8859-1
       Encoding: text/plain
       Newsgroup-Type: Discussion
       Hier-Type: Int
       Name-Length: 14
       Date-Create: 199201060000
       .

   <-- HIER bln
   --> 401
       Permission denied
       .

   <-- HIER
   --> 530 There is an error
       missing parameter hierarchy
       .


6.3.3.9.  DATA

   Description

   The DATA command corresponds to the HIER command, but it is used for
   information about a newsgroup. A summary of codes can be found in
   section 6.3.4.

   data-cmd =  "DATA" [ WSP range ] 1*( WSP newsgroup-name ) CRLF




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   Possible answers

   401: Permission denied
   530: Missing parameter
   612: Regular answer with all requested data

   data-answer =  "612" [ answertext ] CRLF
                  *( datadata CRLF )
                  "." CRLF
               =/ "530" [ answertext ] CRLF )
                  text CRLF
                  "." CRLF
               =/ "401" [ answertext ] CRLF
                  text CRLF
                  "." CRLF

   datadata    =  "Name:" WSP test CRLF
                  "Status:" WSP text CRLF
                  *( header ":" WSP text CRLF )
                  ( "Ctl-PGP-Key:" CRLF PGP-answer )
                  ( "Mod-PGP-Key:" CRLF PGP-answer )

   Examples

   <-- DATA de.comp.os.unix.linux.moderated
   --> 612 data follow
       Name de.comp.os.unix.linux.moderated
       Status: Group-Moderated
       Description: Linux und -Distributionen.
                                <dcoulm-moderators@linux-config.de>
       Charter: http://www.dana.de/mod/chartas/de.comp.html#de.comp.
                                           os.unix.linux.moderated
       Netiquette: http://www.dana.de/de/netiquette.html
       Netiquette: ftp://ftp.fu-berlin.de/doc/usenet/german
                                                     /netiquette.gz
       Mod-Sub-Adr: dcoulm-moderators@linux-config.de
       Mod-Group-Info: http://wpxx02.toxi.uni-wuerzburg.de/~dcoulmod/
       Newsgroup-Type: Discussion
       .

   <-- DATA de.foo
   --> 612 data follow
       Name: de.foo
       Status: Incomplete
       .

   <-- DATA de
   --> 401



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       Permission denied
       .

   <-- DATA
   --> 530
       missing parameter newsgroup
       .


6.3.3.10.  GETL

   Description

   The GETL command is intended for server-server communication; it will
   request the list of packages that a server is offering. A package is
   the complete information available for a hierarchy or newsgroup, i.e.
   all entries that have a value including PGP keys. The format of the
   data is the same as for the commands "HIER" and "LIST".

   The server will send a list of available and distributable hierarchy
   packages.

   getl-cmd =  "GETL" CRLF

   Possible answers

   401: Permission denied
   614: Lists all packages a server is authoritative for

   getl-answer =  "614" [ answertext ] CRLF
                  *( getldata )
                  "." CRLF
               =/ "401" [ answertext ] CRLF
                  text CRLF
                  "." CRLF


   getldata    = *( newsgroup-name CRLF )

   Examples

   <-- GETL
   --> 614 data follow
       de
       .

   <-- GETL
   --> 614 data follow



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       de
       hk
       comp
       rec
       [...]
       bln
       .


6.3.3.11.  GETP

   Description

   GETP requests the packages specified by the parameter "Package". If
   "*" is given as package name, all data the server is offering will be
   transmitted. The "serial" is the date and time the package was last
   obtained by the client, so the server can check if the data on the
   client side is still valid or if it is too old. If the data on the
   client side is still valid a 213 answer is sent, so the client knows
   that his data is ok. If the serial is "0", the server is forced to
   transmit the data.

   The data for a successful request are sent in ASCII armor according
   to [RFC2440], so a client has the possibility to check the signature
   or to ignore it. The actual data will be surrounded by an indicator
   which indicates the signing method, the beginning mark, and the end
   mark. These specifications will be included in the signed text block.

   getp-cmd =  "GETP" WSP password WSP serial
               WSP ( "0" / *[ WSP hierarchy-name ] ) CRLF

   password =  *VCHAR / "0"

   serial   =  utc-time ; date and time of the last retrieval
            =/ "0"      ; force the transmission of data

   Possible answers

   213: Current data at the client side
   411: No package with that name
   430: Permission denied
   530: Missing parameter
   613: Package data

   getp-answer =  "613" [ answertext ] CRLF
                  pgp-start-mark ; this is according to [RFC2440]
                  "GETP" WSP "SIGN" WSP method CRLF
                  "GETP" WSP "BEGIN" CRLF



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                  *( getpdata CRLF)
                  "GETP" WSP "END" CRLF
                  pgp-end-mark ; this is according to [RFC2440]
                  "." CRLF
               =/ "213" [ answertext ] CRLF
                  text CRLF
                  "." CRLF
               =/ "430" [ answertext ] CRLF
                  text CRLF
                  "." CRLF
               =/ "411" [ answertext ] CRLF
                  text CRLF
                  "." CRLF
               =/ "530" [ answertext ] CRLF
                  text CRLF
                  "." CRLF

   Currently the following methods are supported:

   method      =  "PGP2" / "PGP5" / "GPG"
                  ; PGP version 2, PGP version 5 and GnuPG

   pgp-start-mark and the pgp-end-mark are build according to [RFC2440]
   Section 6.2. "Forming ASCII Armor".

   getpdata   =  "Name:" WSP test CRLF
                  "Status:" WSP text CRLF
                  *( header ":" WSP text CRLF )
                  ( "Ctl-PGP-Key:" CRLF PGP-answer )
                  ( "Mod-PGP-Key:" CRLF PGP-answer )


   Examples

   <-- GETP 0 0 humanities
   --> 613 data follow
       -----BEGIN PGP SIGNED MESSAGE-----

       GETP SIGN PGP2
       GETP BEGIN
       Name: humanities
       Status: Hierarchy-Complete
       Description: branches of learning that investigate human
                 constructs and concerns as opposed to natural processes
       Netiquette: ftp://rtfm.mit.edu/pub/usenet/news.announce.newusers/
                       A_Primer_on_How_to_Work_With_the_Usenet_Community
       Rules: http://www.uvv.org/formus/big8creation.htm
       Ctl-Send-Adr: group-admin@isc.org



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       Ctl-Newsgroup: news.announce.newgroup
       Lanugage: EN
       Chatset: US-ASCII
       Encoding: text/plain
       Newsgroup-Type: Discussion
       Hier-Type: Global
       Comp-Length: 14
       Date-Create: 19950417143009
       Name:  humanities.answers
       Status:  Moderated
       Description: Repository for periodic USENET articles. (Moderated)
       Mod-Sub-Adr: news-answers@mit.edu
       Mod-Adm-Adr: news-answers-request@mit.edu
       Newsgroup-Type: Announce
       Date-Create: 19950725182040
       Name: humanities.classics
       [...]
       GETP END


       -----BEGIN PGP SIGNATURE-----
       Version: 2.6.3in
       Charset: noconv

       iQCVAwUBOBhmWTiii3auEmclAQEM9wP9FVem1VXYrywFa2FLEh1apsay9yJC9jKT
       V80U1M1LAKkR+xkXZdczd/PIGEAQapauKjINpxFOgynMWd8A2Ta0y4s4ZXHgEiZP
       A/tKaMGi/7roZwUp8ERQRBsvc54kckgnX57HiVUgsbVd41FHPTvsVLv/QIHmqaGd
       fR5aQJfwKhE=
       =Sg4p
       -----END PGP SIGNATURE-----
       .

   <-- GETP 0 199909091010 de
   --> 213
       You are uptodate
       .

   <-- GETP foo
   --> 530
       Missing parameters
       .


   <-- GETP test 0 de
   --> 430
       You have no permission to retrieve the data
       Cause: Wrong IP number
       .



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6.3.3.12.  GETA

   Description

   The GETA command is used for server-server communication; it will
   request packages that the server is authoritative for. A package is
   the authoritative data either for a newsgroup or a hierarchy. Each
   package has a serial number attached to control the age of the
   package.  Serial is a number that is the date in UTC format of the
   last known modification of the package. A serial of "0" indicates
   that the package MUST be retrieved. If the retrieving client has a
   recent package (i.e. no modification on the authoritative server) the
   server sends only a 215 response.  The format of the data is the same
   as for the commands "HIER" and "LIST".

   geta-cmd =  "GETA" WSP password WSP serial WSP hierarchy-name CRLF

   password =  *VCHAR / "0"

   Possible answers

   215: The client already has the current data
   430: Permission denied
   411: No package with that name
   530: Missing parameter
   615: Regular answer with all requested data

   geta-answer =  "615" [ answertext ] CRLF
                  pgp-start-mark ; this is according to [RFC2440]
                  "GETA" WSP "SIGN" WSP method CRLF
                  "GETA" WSP "BEGIN" CRLF
                  *( getadata CRLF)
                  "GETA" WSP "END" CRLF
                  pgp-end-mark ; this is according to [RFC2440]
                  "." CRLF
               =/ "215" [ answertext ] CRLF
                   text CRLF
                   "." CRLF
               =/ "430" [ answertext ] CRLF
                  text CRLF
                  "." CRLF
               =/ "411" [ answertext ] CRLF
                  text CRLF
                  "." CRLF
               =/ "530" [ answertext ] CRLF
                  text CRLF
                  "." CRLF




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   geta-data = 2*( *( datacode "-" text CRLF ) datacode WSP text)

   Examples

   <-- GETA 0 0 humanities
   --> 613 data follow
       -----BEGIN PGP SIGNED MESSAGE-----

       GETA SIGN PGP2
       GETA BEGIN
       Name: humanities
       Status: Hierarchy
       Description: the branches of learning that investigate human
                 constructs and concerns as opposed to natural processes
       Netiquette: ftp://rtfm.mit.edu/pub/usenet/news.announce.newusers/
                       A_Primer_on_How_to_Work_With_the_Usenet_Community
       Rules: http://www.uvv.org/formus/big8creation.htm
       Ctl-Send-Adr: group-admin@isc.org
       Ctl-Newsgroup: news.announce.newgroup
       Language: EN
       Chartset: US-ASCII
       Encoding: text/plain
       Newsgroup-Type: Dissusion
       Hier-Type: Int
       Comp-Length: 14
       Date-Create: 19950417143009
       Name:  humanities.answers
       Status:  Moderated
       Description: Repository for periodic USENET articles. (Moderated)
       Mod-Sub-Adr: news-answers@mit.edu
       Mod-Adm-Adr: news-answers-request@mit.edu
       Newsgroup-Type: Announce
       Date-Create: 19950725182040
       Name: humanities.classics
       [...]
       GETA END


       -----BEGIN PGP SIGNATURE-----
       Version: 2.6.3in
       Charset: noconv

       iQCVAwUBOBhmWTiii3auEmclAQEM9wP9FVem1VXYrywFa2FLEh1apsay9yJC9jKT
       V80U1M1LAKkR+xkXZdczd/PIGEAQapauKjINpxFOgynMWd8A2Ta0y4s4ZXHgEiZP
       A/tKaMGi/7roZwUp8ERQRBsvc54kckgnX57HiVUgsbVd41FHPTvsVLv/QIHmqaGd
       fR5aQJfwKhE=
       =Sg4p
       -----END PGP SIGNATURE-----



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       .


6.3.3.13.  Unknown Commands and Syntax Errors

   If a command is recognized as unknown, it MUST be ignored. If an
   error occurs after the command string (e.g. a missing parameter) a
   530 return code is given.




6.3.4.  Data Headers

   The following descriptions are keywords and key terms which support
   retrieval and storing of information.  Every header has a unique
   English name.

   The content of a header is inheritable within a hierarchy, as long as
   the header is marked as inheritable. The content is the default value
   for all downstream newsgroups and sub-hierarchies. For example in the
   hierarchy "de" the language header has a value of "DE" (German),
   therefore this value is true for all newsgroups in this hierarchy,
   except those who explicitly define a language code of their own.

   Hierarchies and newsgroups must at least have values for the header
   "Name" and "Status". Unknown hierarchies get the status "Incomplete"
   and unknown groups get the status "Unkown".

   The header names used in the NAS protocol are not case sensitive. A
   header may be upper case, lower case, or any mixture of upper and
   lower case. But the prefered syntax is the first letter upper case up
   to the end or a dash lower case, after a dash the first letter is
   again upper case then lower case and so on.

   Name

   Name:        Name

   Used for:    hierarchy
   Mandatory:   yes
   Inheritable: no
   Repeatable:  no
   Description: Name of a hierarchy
   Comment:     Start of a new data block
   Example:     Name: comp

   Used for:    newsgroup



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   Mandatory:   yes
   Repeatable:  no
   Description: Name of a newsgroup
   Comment:     Start of a new data block
   Example:     Name: de.admin.news.announce


   Status

   Name:        Status

   Used for:    hierarchy
   Mandatory:   yes
   Inheritable: no
   Repeatable:  no
   Description: Status of a hierarchy
   Comment:     For a detailed description see section 6.4.
   Example:     Status: Hierarchy-Complete

   Used for:    newsgroup
   Mandatory:   yes
   Repeatable:  no
   Description: Status of a newsgroup
   Comment:     For a detailed description see section 6.4.
   Example:     Status: Group-Moderated


   Group for followup

   Name:        Followup

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  no
   Description: Name of the newsgroup, that will take the followup
                postings of a moderated group.
   Comment:     The value can be used as default value for the
                "Followup-To:" header on postings to a moderated group.
                This value is only useful on groups which are moderated
                (Status M) and have a dedicated discussion group.
   Example:     Followup: bln.announce.fub.zedat.d
                (for the moderated group bln.announce.fub.zedat)


   Short description

   Name:        Description




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   Used for:    hierarchy
   Mandatory:   no
   Inheritable: no
   Repeatable:  no
   Description: Short description of a hierarchy
   Example:     Description: Angelegenheiten, die den Grossraum Berlin
                                                             betreffen
                (for the hierarchy bln)

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  no
   Description: Short description of a newsgroup
   Comment:     This information is often presented to the news reader
                upon selection of the newsgroup, and it should describe
                the topics in brief, but meaningful.
   Example:     Description: Technisches zur Newssoftware
                (for de.admin.news.software)


   Charter-URL

   Name:        Charter

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: no
   Repeatable:  yes
   Description: URL that points to the charter of a hierarchy
   Example:     Charter: ftp://ftp.fu-berlin.de/doc/news/bln/bln
                (for the hierarchy bln)

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  yes
   Description: URL that points to the charter of a newsgroup
   Comment:     This information should be presented to the
                news reader upon selection of the newsgroup.
   Example:     Charter: http://www.dana.de/mod/charta/admin.html


   Netiquette-URL

   Name:        Netiquette

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes



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   Repeatable:  yes
   Description: URL that points to the netiquette of a hierarchy.
   Comment:     Since the netiquettes are often valid for
                a complete hierarchy this is inheritable.
   Example:     Netiquette: http://www.dana.de/mod/netiquette.html

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  yes
   Description: URL for Netiquette
   Comment:     If a group has some special rules, this is the
                pointer to these rules.
   Example:     Netiquette: http://research.de.uu.net:8080/
                                              de.sci.announce/faq
                (for de.sci.announce)


   Frequently Asked Questions (FAQ)

   Name:        FAQ

   Used for:    Newsgroup
   Mandatory:   no
   Repeatable:  yes
   Description: URL for the FAQ of a newsgroup
   Example:     FAQ: http://www2.informatik.uni-wuerzburg.de/dclc-faq/
                (for de.comp.lang.c)


   Administration rules

   Name:        Rules

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  yes
   Description: URL pointing to a document that describes the rules for
                creating, deleting or renaming newsgroups in this
                hierarchy.
   Comment:     Normally inherited from the (toplevel)
                hierarchy
   Example:     Rules: http://www.dana.de/mod/einrichtung.html
                (for the hierarchy de)


   Control Email




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   Name:        Ctl-Send-Adr

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  yes
   Description: Email address of the sender of control messages
   Comment:     Multiple addresses are valid
   Example:     Ctl-Send-Adr: group-admin@isc.org
                (for the hierarchy sci)


   Control newsgroup

   Name:        Ctl-Newsgroup

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  yes
   Description: Name of the newsgroup that will get the postings for
                checkgroups, rmgroup and newsgroup control messages.
   Example:     Ctl-Newsgroup: de.admin.news.groups


   Moderators

   Name:        Mod-Wildcard

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  no
   Description: Moderator wildcard for this hierarchy.
   Comment:     This information can be used by the configuration of the
                news system, for example the moderators file in INN.
   Example:     Mod-Wildcard: %s@moderators.dana.de
                (for the hierarchy de)


   Submission address

   Name:        Mod-Sub-Adr

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  yes
   Description: Email address for submissions to the newsgroup.



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   Comment:     If there is no "Mod-Sub-Adr" for a moderated newsgroup,
                "Mod-Wildcard" of the hierarchy is used. This is only
                useful for moderated groups (Status Moderated).
   Example:     Mod-Sub-Adr: news-answers@mit.edu
                (for the newsgroup news.answers)


   Moderator's address (email)

   Name:        Mod-Adm-Adr

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  yes
   Description: Email address of the moderator for the newsgroup.
   Comment:     If there is no code "Mod-Adm-Adr" for a moderated
                newsgroup, "Mod-Wildacard" of the hierarchy is used.
                This is only useful for moderated groups
                (Status Moderated).
   Example:     Mod-Adm-Adr: news-answers-request@mit.edu
                (for the newsgroup news.answers)


   Info-URL

   Name:        Mod-Group-Info

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  yes
   Description: URL that points to a document, where the moderator
                presents information about the newsgroup and the
                submission of articles.
   Example:     Mod-Group-Info: http://www.cs.helsinki.fi/u/mjrauhal/
                                                 linux/cola-submit.html
                (for comp.os.linux.announce)


   Language

   Name:        Language

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  yes
   Description: The language that will normally be used in postings
   Comment:     The notation is according to [RFC1766], the



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                "Content-Language" field.  The languages that are not
                the preferred language are enclosed in parenthesis.
   Example:     Language: DE
                (for the hierarchy de)

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  yes
   Description: The language that will normally be used in postings.
   Comment:     The notation is according to [RFC1766], the
                "Content-Language" field. The languages that are not
                the preferred language are enclosed in parenthesis.
   Example:     Language: TR
                          DE
                          (EN)
                (for the newsgroup bln.kultur.tuerkisch)


   Charset

   Name:        Charset

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  yes
   Description: Charset that will normally be used in postings in this
                hierarchy.
   Comment:     The complete set of charset names is defined by
                [RFC2277] and the IANA Character Set registry [IANA-CS].
                The charsets that are not the preferred charsets are
                enclosed in parenthesis.
   Example:     Charset: ISO-8859-1
                (for the hierarchy de)

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  yes
   Description: Charset that will normally be used in
                postings in this group.
   Comment:     The complete set of charset names is defined by
                [RFC2277] and the IANA Character Set registry
                [IANA-CS]. The charsets that are not the preferred
                charsets are enclosed in parenthesis.
   Example:     Charset: ISO-8859-9
                         ISO-8859-1
                (for the newsgroup bln.kultur.tuerkisch)




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   Encoding

   Name:        Encoding

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  yes
   Description: Encoding for this hierarchy according to MIME [RFC2045]
   Comment:     This is the media type used in this hierarchy, a list of
                registered media types can be found at [IANA-MT]. The
                encodings that are not the preferred encoding are
                enclosed in parenthesis.
   Example:     Encoding text/plain

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  yes
   Description: Encoding for this newsgroup according to MIME [RFC2045]
   Comment      This is the media type used in this newsgroup, a list of
                registered media types can be found at [IANA-MT]. The
                encodings that are not the preferred encoding are
                enclosed in parenthesis.
   Example:     Encoding: text/plain


   Type of newsgroup

   Name:        Newsgroup-Type

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  yes
   Description: Default newsgroup type in this hierarchy
   Comment:     This code has no concrete meaning for a hierarchy, but
                is used for the inheritance to newsgroups in the
                hierarchy.
                Specification of the types can be found in section 6.5
   Example:     Newsgroup-Type: Discussion
                (for the hierarchy de)

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  yes
   Description: Type of newsgroup
   Comment:     Specification of the types can be found in section 6.6
   Example:     Newsgroup-Type: Announce



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                (for de.admin.news.announce)


   Type of hierarchy

   Name:        Hier-Type

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  yes
   Description: Type of hierarchy
   Comment:     Specification of the types can be found in section 6.6
   Example:     Hier-Type: Regional
                (for hierarchy bln)


   Regional or organizational area

   Name:        Area

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  yes
   Description: Description of the geographical region or organization
                of this hierarchy
   Comment:     This code is useful when the hierarchy type
                (Hier-type) is "Regional" or "Organisation".
   Example:     Area: Grossraum Berlin
                (for the hierarchy bln)


   Name length of group names

   Name:        Name-Length

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  no
   Description: Maximum length of a newsgroup name
   Example:     Name-Length: 72
                (for the hierarchy bln)


   Component length of group names




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   Name:        Comp-Length

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  no
   Description: Maximum length of a single component in the newsgroup
                name
   Example:     Comp-Length: 14
                (for the hierarchy de)


   Article length

   Name:        Article-Length

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  no
   Description: Maximum length of an article in bytes.
   Comment:     This code has no concrete meaning for a hierarchy, but
                is used for the inheritance to newsgroups in the
                hierarchy.
   Example:     Article-Length: 50000

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  no
   Description: Maximum length of an article in bytes
   Example:     Article-Length: 50000


   Date of creation

   Name:        Date-Create

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  no
   Description: Creation date of a hierarchy (can even be in future).
   Comment:     The format is the same as in the DATE command.
   Example:     Date-Create: 19970330101514

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  no



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   Description: Creation date of a newsgroup (can even be in future).
   Comment:     The format is the same as in the DATE command.
   Example:     Date-Create: 19970330101514


   Date of removal

   Name:        Date-Delete

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  no
   Description: Date of removal of a hierarchy (can even be in future).
   Comment:     The format is the same as in the DATE command.
   Example:     Date-Delete: 19970330101514

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  no
   Description: Date of removal of a newsgroup (can even be in future).
   Comment:     The format is the same as in the DATE command.
   Example:     Date-Delete: 19970330101514


   Successor

   Name:        Replacement

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: no
   Repeatable:  yes
   Description: Name of the hierarchy that replaced a removed hierarchy
                if status is O or will replace a hierarchy if the date
                of removal is in the future.
   Example:     Replacement: de
                (for the hierarchy sub)

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  yes
   Description: Name of the newsgroup or newsgroups that will replace a
                removed newsgroup if status is X or will replace the
                newsgroup if the date of removal is in the future.
   Example:     Replacement: bln.markt.arbeit
                (for bln.jobs)




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   Source

   Name: Source

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  no
   Description: Name of the organization/person that is responsible for
                this hierarchy. SHOULD be a URL or email.
   Example:     Source: http://www.dana.de/mod/
                (for the hierarchy de)

NOTE: This is for tracking the maintainer of an hierarchy


   Control PGP key

   Name:        Ctl-PGP-Key

   Used for:    hierarchy
   Mandatory:   no
   Inheritable: yes
   Repeatable:  yes
   Description: PGP key (with additional information: key owner, key-id,
                etc.) of the sender of control messages in this
                hierarchy.
   Comment:     The exact format is described in section 6.7.
   Example:     Ctl-PGP-Key:
                U de.admin.news.announce
                B 1024
                I D3033C99
                L http://www.dana.de/mod/pgp/dana.asc
                L ftp://ftp.isc.org/pub/pgpcontrol/PGPKEYS.gz
                F 5B B0 52 88 BF 55 19 4F  66 7D C2 AE 16 26 28 25
                V 2.6.3ia
                K------BEGIN PGP PUBLIC KEY BLOCK-----
                K-Version: 2.6.3ia
                K-
                K-mQCNEALZ+Xfm/WDCEMXM48gK1PlKG6TkV3SLbXt4CnzpGM0tOMa
                K-HjlHqM1wEGUHD5hw/BL/heR5Tq+C5IEyXQQmYwkrgeVFMOz/rAQ
                [...]
                K-SDw+iQgAAtN6zrYOhHFBp+
                K-VpvRovMz+lSOy9Zcsbs+5t8Pj9ZVAQyfxBkqD5A=
                K-=Xwgc
                K -----END PGP PUBLIC KEY BLOCK-----





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   Moderator's PGP key

   Name:        Mod-PGP-Key

   Used for:    newsgroup
   Mandatory:   no
   Repeatable:  yes
   Description: Public PGP key (with additional information: key owner,
                key-id, etc) of this newsgroup's moderator.
   Comment:     The exact format is described in section 6.7
   Example:     see section 6.7


6.4.  Status Indicators

   The status indicator is used as a unique indicator of the status of a
   hierarchy or newsgroup. The indicator is case-insensitive.

   Indicator            Type      Description
   -------------------- --------- -------------------------------------
   Hierarchy-Complete   hierarchy authorized, complete known hierarchy
   Hierarchy-Incomplete hierarchy not completely known hierarchy
   Hierarchy-Obsolete   hierarchy obsolete hierarchy, should contain
                                  only newsgroups with status "Removed"
   Hierarchy-Unkown     hierarchy no information available,
                                  unknown hierarchy
   Group-Post-Yes       newsgroup posting allowed, unmoderated
   Group-Post-No        newsgroup posting not allowed
   Group-Moderated      newsgroup moderated group, articles must be
                                  sent to the moderator
   Group-Removed        newsgroup deleted or renamed newsgroup, no
                                  posting or transport
   Group-Unknown        newsgroup unknown group, no information
                                  available
   -------------------- --------- -------------------------------------



6.5.  Newsgroup Types

   A comprehensive overview about some characteristics of a newsgroup,
   being a test group, a binary group and so on. The indicator is case-
   insensitive.

   Code       Use of a newsgroup
   ---------- ----------------------------------------------------
   Discussion discussion (text postings)
   Binary     (encoded) binary postings



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   Sources    source postings (e.g., comp.unix.sources)
   Announce   announcements, press releases, RfD/CfV
   Test       test postings, sometimes reflectors (e.g., de.test)
   Robots     automatic postings (e.g., comp.mail.maps)
   Experiment experimental, other
   ---------- ----------------------------------------------------


6.6.  Hierarchy Types

   To describe a hierarchy the following codes are used. These flags are
   used to mark some properties of a news hierarchy.  The indicator is
   case-insensitive.

   Code           Type of hierarchy
   -------------- ---------------------------------------------------
   Global         international, global hierarchy
                  (e.g., the hierarchies comp, de, rec)
   Regional       regional hierarchy
                  (e.g., the hierarchies ba, bln, tor)
   Alt            alternative hierarchy, simpler rules for
                  creating a group, no formal structure
                  (e.g., the hierarchy alt)
   Non-Commercial only for personal use, commercial use is prohibited
                  (e.g., the hierarchy de)
   Commercial     commercial use permitted
                  (e.g., the hierarchy biz)
   Organization   hierarchy bound to an organization
                  (e.g., the hierarchy gnu)
   -------------- ---------------------------------------------------


6.7.  PGP Keys

   PGP keys for Ctrl-PGP-Key and Mod-PGP-Key are transmitted in the
   following structure:

   PGP-answer = "V" SP Version CRLF
                "U" SP User-ID CRLF              "B" SP Bits CRLF
                "I" SP Key-ID CRLF
                "F" SP Finger CRLF
                *("L" SP Location CRLF)
                *("K-" Keyblock CRLF) "K" SP Keyblock CRLF

   Key Name      Mandatory Description
   --- --------- --------- --------------------------------------
    K  Keyblock  yes       public key block in ASCII armor format
                           [RFC2440]



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    V  Version   yes       PGP-Version
    U  User-ID   no        key user id
    B  Bits      no        number of bits
    I  Key-ID    no        key id, without leading "0x"
    F  Finger    no        fingerprint
    L  Location  no        URL that points to the public key
   --- --------- --------- --------------------------------------

   A hyphen following the code indicates that the block is continued on
   the next line. In the last message row there must be white space
   after the code, this is also true for a single line code.

    Example

   <-- HIER de
   --> 611 ..
       Name: de
       Status: Hierarchy
       [...]
       Ctl-PGP-Key:
       U de.admin.news.announce
       B 1024
       I D3033C99
       L http://www.dana.de/mod/pgp/dana.asc
       L ftp://ftp.fu-berlin.de/unix/news/pgpcontrol/PGPKEYS.gz
       F 5B B0 52 88 BF 55 19 4F  66 7D C2 AE 16 26 28 25
       V 2.6.3ia
       K------BEGIN PGP PUBLIC KEY BLOCK-----
       K-Version: 2.6.3ia
       K-
       K-mQCNAzGeB/YAAAEEALZ+Xfm/WDCEMXM48gK1PlKG6TkV3SLbXt4CnzpGMtOM
       K-HjlHaU6Xco5ijAuqM1wEGUHD5hw/BL/heR5Tq+C5IEyXQQmYwkrgeVFMO/rA
       [...]
       K-SDw+Id0JPFO9AWOiQgAAtN6zrYOhHFBp+68h9k674Yg9IHqj3BWdRjJF6PKo
       K-VpvRovMz+lSOy9Zcsbs+5t8Pj9ZVAQyfxBkqD5A=
       K-=Xwgc
       K -----END PGP PUBLIC KEY BLOCK-----
       [...]
       .



7.  Specification of the NAS Protocol (UDP)

   UDP is intended for reading programs (news reader), it is not in the
   scope of this document and will be described in a separate paper.





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8.  Security Considerations

   Security issues are only vital for the server-server communication,
   since we want a strict hierarchical model of the netnews
   administration system. So we want to be sure that only authorized
   clients connect to an authoritative server.

   Every server has the possibility to deny some commands or the whole
   connection based on the client's IP number.

Note: A stronger authentication scheme will be provided in a higher
protocol level.


9.  References


   [IANA-CS] IANA: Character Sets
             ftp://ftp.isi.edu/in-notes/iana/assignments/character-sets

   [IANA-MT] IANA: Media Types   ftp://ftp.isi.edu/in-notes/iana/
             assignments/media-types/media-types

   [IANA-PN] IANA: Assigned Port Numbers
             ftp://ftp.isi.edu/in-notes/iana/assignments/port-numbers

   [RFC1036] Horton, M., and Adams, R., "Standard for Interchange of
             USENET Messages", RFC 1036, AT&T Bell Laboratories/
             Center for Seismic Studies, December 1987

   [RFC1305] Mills, D.L., "Network Time Protocol", RFC 1305,
             University of Delaware, March 1992

   [RFC1700] Reynolds, J., and J. Postel, "Assigned Numbers", STD 2, RFC
             1700, USC/ISI, October 1994.

   [RFC1766] Alvestrand, H., "Tags for the Identification of
             Languages", RFC 1766, March 1995.

   [RFC2026] Bradner, S., "The Internet Standards Process - Revision 3",
             RFC 2026, Harvard University, October 1996

   [RFC2045] Freed, N. and Borenstein, N., "Multipurpose Internet Mail
             Extensions (MIME)", RFC 2045, Innosoft/First Virtual,
             November 1996

   [RFC2119] Bradner, "Key words for use in RFCs to Indicate Requirement
             Levels", RFC 2119, Harvard University, March 1997.



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   [RFC2234] Crocker, Overell, "Augmented BNF for Syntax Specifications:
             ABNF", RFC 2234, November 1997.

   [RFC2277] Alvestrand, H., "IETF Policy on Character Sets and
             Language", RFC 2277, January 1998

   [RFC2440] Callas, J., Donnerhacke, L., Finney, H. and R.  Thayer,
             "OpenPGP Message Format", RFC 2240, November 1998.

   [SON1036] Henry Spencer, "News Article Format and Transmission",
             A Draft for an RFC 1036 Successor,
             ftp://zoo.toronto.edu/pub/news.txt.Z

   [USEFOR]  USEFOR Working Group, "News Article Format"
             draft-ietf-usefor-article-02


10.  Author's Address

   Philipp Grau, Vera Heinau, Heiko Schlichting
   Freie Universitaet Berlin
   ZEDAT, DFN-CIS
   Fabeckstr. 32
   14195 Berlin
   Germany

   Phone: +49 30 838-56583
   Fax:   +49 30 838-56721

   Email: nas@cis.fu-berlin.de
   WWW: http://nas.cis.fu-berlin.de/


Appendix A - Response Codes (Overview)

   Code  Description
   ----  ---------------------------------------------------------------
   100   Command overview, Infomation command description (HELP)
   101   Information about connection, client and server (INFO)
   200   Greeting message (Connection Setup)
   201   Termination of the connection (QUIT)
   202   Returns current protocol level (VERS)
   213   Valid data at the client side (GETP)
   215   The client already has the current data (GETA)
   300   Time in UTC (DATE)
   302   Answer to an successful request (VERS)
   400   Indicates that the server is not giving any information (INFO)
   401   Permission denied (LIST, LSTR, HIER, DATA, GETL)



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   402   Requested level too high, falling back to lower level (VERS)
   404   Server currently out of service (Connection Setup)
   410   Indicates that the server is not giving any information (HELP)
   411   No package with that name (GETP, GETA)
   430   Permission denied (GETP, GETA)
   434   Client has no permission to talk to server (Connection Setup)
   510   Syntax error (VERS)
   511   Internal error (TIME)
   530   Missing parameter (LIST, LSTR, HIER, DATA, GETP, GETA)
   610   Regular answer with all requested data (LIST,LSTR)
   611   Regular answer with all requested data (HIER)
   612   Regular answer with all requested data (DATA)
   613   Package data (GETP)
   614   Lists all packages a server is authoritative for (GETL)
   615   Regular answer with all requested data (GETA)
   ----  ---------------------------------------------------------------


Appendix B - Data Header for DATA and HIER Commands (Overview)

   Name            Mandatory  Use Multiple Description
   --------------- ---------- --- -------- ------------------------
   Name                yes    H/N    no    Name of a hierarchy or
                                           newsgroup (Start of a
                                           new data block)
   Status              yes    H/N    no    Status of hierarchy or
                                           newsgroup
   Followup            no       N    no    Group for followup
   Description         no     H/N    no    Short description of a
                                           hierarchy/newsgroup
   Charter             no     H/N    yes   Charter-URL
   Netiquette          no     H/N    yes   Netiquette-URL
   FAQ                 no       N    yes   FAQ-URL
   Rules               no     H      yes   Administration rules URL
   Ctl-Send-Adr        no     H      yes   Control email
   Ctl-Newsgroup       no     H      yes   Control newsgroup
   Mod-Wildcard        no     H      no    Moderator wildcard
   Mod-Sub-Adr         no       N    no    Submission address
   Mod-Adm-Adr         no       N    yes   Moderator's address
                                           (email)
   Mod-Group-Info      no       N    yes   Info-URL
   Language            no     H/N    yes   Language
   Charset             no     H/N    yes   Charset
   Encoding            no     H/N    yes   Encoding
   Newsgroup-Type      no     H/N    yes   Type of newsgroup
   Hier-Type           no     H      yes   Type of hierarchy
   Area                no     H      yes   Regional or
                                           organizational area



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   Name-Length         no     H      no    Total length of group
                                           names
   Comp-Length         no     H      no    Component length of
                                           group names
   Article-Length      no     H      no    Article length
   Date-Create         no     H/N    no    Date of creation
   Date-Delete         no     H/N    no    Date of removal
   Replacement         no     H/N    yes   Successor
   Source              no     H      yes   Source of data
   Ctl-PGP-Key         no     H      yes   Control PGP key
   Mod-PGP-Key         no       N    yes   Moderator's PGP key
   --------------- ---------- --- -------- ------------------------

   Expires November 27, 2000





































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