rfc1939-pop3.txt

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             C: STAT
             S: +OK 2 320


      LIST [msg]

         Arguments:
             a message-number (optional), which, if present, may NOT
             refer to a message marked as deleted





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RFC 1939                          POP3                          May 1996


         Restrictions:
             may only be given in the TRANSACTION state

         Discussion:
             If an argument was given and the POP3 server issues a
             positive response with a line containing information for
             that message.  This line is called a "scan listing" for
             that message.

             If no argument was given and the POP3 server issues a
             positive response, then the response given is multi-line.
             After the initial +OK, for each message in the maildrop,
             the POP3 server responds with a line containing
             information for that message.  This line is also called a
             "scan listing" for that message.  If there are no
             messages in the maildrop, then the POP3 server responds
             with no scan listings--it issues a positive response
             followed by a line containing a termination octet and a
             CRLF pair.

             In order to simplify parsing, all POP3 servers are
             required to use a certain format for scan listings.  A
             scan listing consists of the message-number of the
             message, followed by a single space and the exact size of
             the message in octets.  Methods for calculating the exact
             size of the message are described in the "Message Format"
             section below.  This memo makes no requirement on what
             follows the message size in the scan listing.  Minimal
             implementations should just end that line of the response
             with a CRLF pair.  More advanced implementations may
             include other information, as parsed from the message.

                NOTE: This memo STRONGLY discourages implementations
                from supplying additional information in the scan
                listing.  Other, optional, facilities are discussed
                later on which permit the client to parse the messages
                in the maildrop.

             Note that messages marked as deleted are not listed.

         Possible Responses:
             +OK scan listing follows
             -ERR no such message

         Examples:
             C: LIST
             S: +OK 2 messages (320 octets)
             S: 1 120



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RFC 1939                          POP3                          May 1996


             S: 2 200
             S: .
               ...
             C: LIST 2
             S: +OK 2 200
               ...
             C: LIST 3
             S: -ERR no such message, only 2 messages in maildrop


      RETR msg

         Arguments:
             a message-number (required) which may NOT refer to a
             message marked as deleted

         Restrictions:
             may only be given in the TRANSACTION state

         Discussion:
             If the POP3 server issues a positive response, then the
             response given is multi-line.  After the initial +OK, the
             POP3 server sends the message corresponding to the given
             message-number, being careful to byte-stuff the termination
             character (as with all multi-line responses).

         Possible Responses:
             +OK message follows
             -ERR no such message

         Examples:
             C: RETR 1
             S: +OK 120 octets
             S: <the POP3 server sends the entire message here>
             S: .


      DELE msg

         Arguments:
             a message-number (required) which may NOT refer to a
             message marked as deleted

         Restrictions:
             may only be given in the TRANSACTION state






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RFC 1939                          POP3                          May 1996


         Discussion:
             The POP3 server marks the message as deleted.  Any future
             reference to the message-number associated with the message
             in a POP3 command generates an error.  The POP3 server does
             not actually delete the message until the POP3 session
             enters the UPDATE state.

         Possible Responses:
             +OK message deleted
             -ERR no such message

         Examples:
             C: DELE 1
             S: +OK message 1 deleted
                ...
             C: DELE 2
             S: -ERR message 2 already deleted


      NOOP

         Arguments: none

         Restrictions:
             may only be given in the TRANSACTION state

         Discussion:
             The POP3 server does nothing, it merely replies with a
             positive response.

         Possible Responses:
             +OK

         Examples:
             C: NOOP
             S: +OK


      RSET

         Arguments: none

         Restrictions:
             may only be given in the TRANSACTION state

         Discussion:
             If any messages have been marked as deleted by the POP3
             server, they are unmarked.  The POP3 server then replies



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RFC 1939                          POP3                          May 1996


             with a positive response.

         Possible Responses:
             +OK

         Examples:
             C: RSET
             S: +OK maildrop has 2 messages (320 octets)

6. The UPDATE State

   When the client issues the QUIT command from the TRANSACTION state,
   the POP3 session enters the UPDATE state.  (Note that if the client
   issues the QUIT command from the AUTHORIZATION state, the POP3
   session terminates but does NOT enter the UPDATE state.)

   If a session terminates for some reason other than a client-issued
   QUIT command, the POP3 session does NOT enter the UPDATE state and
   MUST not remove any messages from the maildrop.

      QUIT

         Arguments: none

         Restrictions: none

         Discussion:
             The POP3 server removes all messages marked as deleted
             from the maildrop and replies as to the status of this
             operation.  If there is an error, such as a resource
             shortage, encountered while removing messages, the
             maildrop may result in having some or none of the messages
             marked as deleted be removed.  In no case may the server
             remove any messages not marked as deleted.

             Whether the removal was successful or not, the server
             then releases any exclusive-access lock on the maildrop
             and closes the TCP connection.

         Possible Responses:
             +OK
             -ERR some deleted messages not removed

         Examples:
             C: QUIT
             S: +OK dewey POP3 server signing off (maildrop empty)
                ...
             C: QUIT



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RFC 1939                          POP3                          May 1996


             S: +OK dewey POP3 server signing off (2 messages left)
                ...

7. Optional POP3 Commands

   The POP3 commands discussed above must be supported by all minimal
   implementations of POP3 servers.

   The optional POP3 commands described below permit a POP3 client
   greater freedom in message handling, while preserving a simple POP3
   server implementation.

      NOTE: This memo STRONGLY encourages implementations to support
      these commands in lieu of developing augmented drop and scan
      listings.  In short, the philosophy of this memo is to put
      intelligence in the part of the POP3 client and not the POP3
      server.

      TOP msg n

         Arguments:
             a message-number (required) which may NOT refer to to a
             message marked as deleted, and a non-negative number
             of lines (required)

         Restrictions:
             may only be given in the TRANSACTION state

         Discussion:
             If the POP3 server issues a positive response, then the
             response given is multi-line.  After the initial +OK, the
             POP3 server sends the headers of the message, the blank
             line separating the headers from the body, and then the
             number of lines of the indicated message's body, being
             careful to byte-stuff the termination character (as with
             all multi-line responses).

             Note that if the number of lines requested by the POP3
             client is greater than than the number of lines in the
             body, then the POP3 server sends the entire message.

         Possible Responses:
             +OK top of message follows
             -ERR no such message

         Examples:
             C: TOP 1 10
             S: +OK



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RFC 1939                          POP3                          May 1996


             S: <the POP3 server sends the headers of the
                message, a blank line, and the first 10 lines
                of the body of the message>
             S: .
                ...
             C: TOP 100 3
             S: -ERR no such message


      UIDL [msg]

      Arguments:
          a message-number (optional), which, if present, may NOT
          refer to a message marked as deleted

      Restrictions:
          may only be given in the TRANSACTION state.

      Discussion:
          If an argument was given and the POP3 server issues a positive
          response with a line containing information for that message.
          This line is called a "unique-id listing" for that message.

          If no argument was given and the POP3 server issues a positive