rfc759.txt

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Internet Message Protocol
Specification



  3.4.3.  Command:  PROBE

    function:  Finds out if specified mailbox (specified in mailbox of
    the command) exists at a host.

    reply:  The reply is RESPONSE.

    arguments:  none.

  3.4.4.  Command:  RESPONSE

    function:  Reply to PROBE.

    arguments:

      reference:  the identification of the originating PROBE.

      address:  a specific address.

      error-class:
      error-string:

        If the mailbox was found the error class is 0 and the error
        string is "OK".  If the mailbox has moved and a forwarding
        address in known the error class is 1 and the error string is
        "Mailbox moved, see address".  Otherwise the error class is
        greater than 1 and the error string may be one of the following:
        "Mailbox doesn't exist", "Mailbox full", "Mailbox has moved, try
        the new location indicated in the address".

      trail:  the trace which came from the originating PROBE.


















[Page 18]                                                         Postel


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                                               Internet Message Protocol
                                                           Specification



  3.4.5.  Command:  CANCEL

    function:  Abort request for specified transaction.

    reply:  The reply is CANCELED.

    arguments:

      reference:  identification of transaction to be canceled.

  3.4.6.  Command:  CANCELED

    function:  Reply to CANCEL.

    arguments:

      reference:  identification of canceled transaction.

      error-class:
      error-string:

        If the command was canceled the error class is 0 and the error
        string is "OK".  Otherwise the error class is positive and the
        error string may be one of the following: "No such transaction",
        or any error for an unreachable mailbox.

      trail:  the trace of the CANCEL command.

  To summarize again, a command generally consists of a property list of
  the following objects:

    name            value
    ----            -----
    mailbox         property list of address information
    operation       name of operation
    arguments       ---
    error-class     numeric class of the error
    error-string    text description of the error
    trace           list ( handling-stamp, ... )

3.5.  Document

  The actual document follows the command.  The message delivery system
  does not depend on the document, examine it, or use it in any way.
  The standard for the contents of the document is reference [25].  The
  document must be the last <name,value> pair in the message property
  list.


Postel                                                         [Page 19]


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Internet Message Protocol
Specification



3.6.  Message Objects

  In the composition of messages, we use a set of objects such as
  mailbox or date.  These objects are encoded in basic data elements.
  Some objects are simple things like integers or character strings,
  other objects are more complex things built up of lists or property
  lists.

  The following is a list of the objects used in messages.  The object
  descriptions are in alphabetical order.

  Action

    The type of handling action taken by the MPM when processing a
    message.  One of ORIGIN, RELAY, FORWARD, or DESTINATION.

  Address

    Address is intended to contain the minimum information necessary to
    deliver a message, and no more (compare with mailbox).

      An address is a property list.  An address contains the following
      <name,value> pairs:

        name    description
        ----    -----------
        NET     network name
        HOST    host name
        USER    user name

      or:

        name    description
        ----    -----------
        MPM     mpm-identifier
        USER    user name

  Answer

    A yes (true) or no (false) answer to a question.

  Arguments

    Many operations require arguments, which differ from command to
    command.  This "object" is a place holder for the actual arguments
    when commands are described in a general way.



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                                               Internet Message Protocol
                                                           Specification



  City

    The character string name of a city.

  Command

    (mailbox, operation [ ,arguments ]
                                  [ ,error-class, error-string ], trace)

  Country

    The character string name of a country.

  Date

    The date and time are represented according to the International
    Standards Organization (ISO) recommendations [26,27,28].  Taken
    together the ISO recommendations 2014, 3307, and 4031 result in the
    following representation of the date and time:

      yyyy-mm-dd-hh:mm:ss,fff+hh:mm

    Where yyyy is the four-digit year, mm is the two-digit month, dd is
    the two-digit day, hh is the two-digit hour in 24 hour time, mm is
    the two-digit minute, ss is the two-digit second, and fff is the
    decimal fraction of the second.  To this basic date and time is
    appended the offset from Greenwich as plus or minus hh hours and mm
    minutes.

    The time is local time and the offset is the difference between
    local time and Coordinated Universal Time (UTC).  To convert from
    local time to UTC algebraically subtract the offset from the local
    time.

    For example, when the time in
              Los Angeles is  14:25:00-08:00
              the UTC is      22:25:00

    or when the time in
              Paris is        11:43:00+01:00
              the UTC is      10:43:00

  Document

    The document is the user's composition and is not used by the
    message delivery system in any way.



Postel                                                         [Page 21]


                                                             August 1980
Internet Message Protocol
Specification



  Error-Class

    A numeric code for the class of the error.  The error classes are
    coded as follows:

      = 0: indicates success, no error.
        This is the normal case.
      = 1: failure, address changed.
        This error is used when forwarding is possible, but not allowed
        by the type of service specified.
      = 2: failure, resources unavailable.
        These errors are temporary and the command they respond to may
        work if attempted at a later time.
      = 3: failure, user error.
        For example, unknown operation, or bad arguments.
      = 4: failure, MPM error.  Recoverable.
        These errors are temporary and the command they respond to may
        work if attempted at a later time.
      = 5: failure, MPM error.  Permanent.
        These errors are permanent, there is no point in trying the same
        command again.
      = 6: Aborted as requested by user.
        The response to a successfully canceled command.


























[Page 22]                                                         Postel


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                                               Internet Message Protocol
                                                           Specification



  Error-String

    This is a character string describing the error.  Possible errors:

              error-string                  error-class

      No errors                                  0
      Ok                                         0
      Mailbox Moved, see address                 1
      Mailbox Full, try again later              2
      Syntax error, operation unrecognized       3
      Syntax error, in arguments                 3
      No Such User                               3
      No Such Host                               3
      No Such Network                            3
      No Such Transaction                        3
      Mailbox Does Not Exist                     3
      Ambiguous Address                          3
      Server error, try again later              4
      No service available                       5
      Command not implemented                    5
      Aborted as requested by user               6

  Handling-Stamp

    The handling-stamp indicates the MPM, the date (including the time)
    that a message was processed by an MPM, and the type of handling
    action taken.

    ( mpm-identifier, date, action )

  Host

    The character string name of a host.

  Identification

    This is the transaction identifier associated with a particular
    message.  It is the transaction number, and the MPM identifier of
    the originating MPM.

    ( mpm-identifier, transaction-number )







Postel                                                         [Page 23]


                                                             August 1980
Internet Message Protocol
Specification



  Internet Address

    This identifies a host in the ARPA internetwork environment.  When
    used as a part of identification, it identifies the originating host
    of a message.  The internet address is a 32 bit number, the higher
    order 8 bits identify the network, and the lower order 24 bits
    identify the host on that network [2].  For use in the MPMs the
    internet address is divided into eight bit fields and the value of
    each field is represented in decimal digits.  For example, the
    ARPANET address of ISIE is 167837748 and is represented as
    10,1,0,52.  Further, this representation may be extended to include
    an address within a host, such as the TCP port of the MPM, for
    example, 10,1,0,52,0,45.

  Mailbox

    This is the destination address of a user of the internetwork mail
    system.  Mailbox contains information such as network, host,
    location, and local user indentifier of the recipient of the
    message.  Some information contained in mailbox may not be necessary
    for delivery.

    As an example, when one sends a message to someone for the first
    time, he may include many items which are not necessary simply to
    insure delivery.  However, once he gets a reply to this message, the
    reply will contain an Address (as opposed to Mailbox) which may be
    used from then on.

      A mailbox is a property list.  A mailbox might contain the
      following <name,value> pairs:

        name    description
        ----    -----------
        MPM     mpm-identifier
        NET     network name
        HOST    host name
        PORT    address of MPM within the host
        USER    user name
        ORG     organization name
        CITY    city
        STATE   state
        COUNTRY country
        ZIP     zip code
        PHONE   phone number

    The minimum mail box is an Address.



[Page 24]                                                         Postel