ietf-nntp MODE READER

Clive D.W. Feather clive at demon.net
Wed Jul 19 01:09:39 PDT 2000


Okay, I think I understand what's going on with MODE READER now. So here is
a proposed rewrite.

  7.  The GREETING Step
 
  7.1 Initial Connection

[Text up to the 7.1.1 heading unchanged and omitted here.]

[New section]

  7.2 Types of client

  Historically, some servers distinguish two types of client:
  * "push" clients, whose main purpose is to send articles using IHAVE.
  * "pull" clients, whose main purpose is to read articles using ARTICLE.
  Each type of client may be prohibited from using commands appropriate
  to the other or may be restricted in other ways. Such servers will
  assume that a client is a push client until told otherwise using the
  MODE READER command.

  Servers SHOULD NOT alter their behaviour depending on whether or not
  the client has used the MODE READER command. Any authentication SHOULD
  be done using the identity of the client (e.g. its IP address) or
  separate authentication extensions. Server authors are encouraged to
  remove any side-effects of MODE READER.

  Clients SHOULD issue a MODE READER command as the first command if
  they intend to use the GROUP, ARTICLE, HEAD, BODY, STATUS, or POST
  commands during the connection. They SHOULD NOT do so if they intend
  to use the IHAVE command.

[Note the renumbering from 7.1.1.]

  7.3  MODE READER

  MODE READER
 
  MODE READER MAY be used by the client to indicate to the server that
  it is a news reading ("pull") client as described in section 7.2.
  This command may be entered at any time. The server MUST present a
  response code appropriate to the server's ability to provide service
  to this client in this mode.

  7.3.1  Responses

      200     posting permitted
      201     posting prohibited
      400     service temporarily unavailable
      502     service permanently unavailable
 
[Note the change in format from example comments to explanation. I think
this is a better approach and I'm doing it whenever I provide new text.]

  Following a 400 or 502 response the server MUST immediately close the
  connection.

  Note that the response need not be the same as the initial greeting.
 
  7.3.2 MODE READER Examples
 
  Example of use of the MODE READER command by an authorized
  client
 
          [C] MODE READER
 
          [S] 200 NNTP Service Ready, posting permitted
 
  Client can send commands at this point.

[Delete the stuff about jumping to QUIT; it's irrelevant.]

  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.

  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.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:  +44 20 8371 1138
Internet Expert     | Home:  <clive at davros.org>  | Fax:  +44 20 8371 1037
Demon Internet      | WWW: http://www.davros.org | DFax: +44 20 8371 4037
Thus plc            |                            | Mobile: +44 7973 377646 



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