rfc841.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

      BASIC     These fields need not be present in  all  messages  but
                when  they do appear, they must be processed by message
                receiving programs as defined  by  the  message  format
                specification.

      OPTIONAL  These  fields  need  not be present in all messages and
                may be ignored by  message  receiving  programs.    The
                exact  meaning  of  "ignored"  is  not specified by the
                message format specification.   However,  a  CBMS  must
                recognize  the existence of an optional field (that is,
                optional fields should not cause errors) and  must  not
                process the field in a manner contrary to the semantics
                defined  for  that field by the message format specifi-
                cation.  It is left to the discretion of a  recipient's
                CBMS  what  action is to be taken when an instance of a
                locally unimplemented optional field is detected.


           (Syntactic compliance is defined in Section 4.1.2.)


      3.1.3  Originator fields


           A message originator may be  a  person,  role,  or  process.
      Originator fields identify a message's author, who is responsible
      for   the   message,   who   or  what  sent  it,  and  where  any
      replies should be directed.  (See Section 2.4.)



                                     18

                                                          Section 3.1.3

      From                     (REQUIRED)

                This  field  contains the identity of the originator(s)
                taking formal responsibility for  this  message.    The
                contents  of  the  From field is to be used for replies
                when no Reply-to field appears in a message.

      Reply-To                 (BASIC)

                This field identifies any recipients of replies to  the
                message.

      Author                   (OPTIONAL)

                This  field  identifies the individual(s) who wrote the
                primary contents of the message.   Use  of  the  Author
                field  is  discouraged  when the contents of the Author
                field and the From field would be completely redundant.

      Sender                   (OPTIONAL)

                This field identifies the agent who sent  the  message.
                It is used either when the sender is not the originator
                responsible  for the message or to indicate who among a
                group  of  originators  responsible  for  the   message
                actually   sent  it.    Use  of  the  Sender  field  is
                discouraged when the contents of the Sender  field  and
                From  field  would be completely redundant.  The sender
                field may specify  only  one  originator  identity  and
                appear only once in a message.


      3.1.4  Recipient fields


           Message  recipients  may  be  people,  roles,  processes, or
      groups.  (See Section 2.4).  Recipient  fields  identify  who  or
      what is to receive the message.

      To                       (REQUIRED)

                This  field  identifies  the  primary  recipients  of a
                message.

      Bcc                      (OPTIONAL)

                This  field  identifies  additional  recipients  of   a
                message  (a  "blind carbon copies" list).  The contents
                of this field are not to be included in copies  of  the
                message  sent  to the primary and secondary recipients.
                See section 3.2.1 for further discussion of the use  of
                blind carbon copies lists.



                                     19

                                                          Section 3.1.4

      Cc                       (BASIC)

                This field identifies secondary recipients of a message
                (a "carbon copies" list).

      Circulate-Next           (OPTIONAL)

                This field is used in conjunction with the Circulate-To
                field.    (See  Section  3.2.6.1.)    It identifies all
                recipients in a circulation list who have not  received
                the message.

      Circulate-To             (OPTIONAL)

                This   field  identifies  recipients  of  a  circulated
                message.   (See  Section  3.2.6.1.)    It  is  used  in
                conjunction with the Circulate-Next field.


      3.1.5  Date fields


           Date  fields  for two kinds of uses are provided.  Dates can
      be associated with some event in the history  of  a  message  and
      dates  can  delimit  the span of time during which the message is
      meaningful (its life span).

      Posted-Date              (REQUIRED)

                This field contains the  posting  date,  which  is  the
                point  in  time  when  the  message  passes through the
                posting slot into a message transfer system.  Only  one
                Posted-Date field is permitted in a message.

      Date                     (OPTIONAL)

                This   field   contains   a  date  that  the  message's
                originator wishes to associate with  a  message.    The
                Date field is to the Posted-Date field as the date on a
                letter is to the postmark added by the post office.

      End-Date                 (OPTIONAL)

                This  field  contains the date on which a message loses
                effect.  (See also Section 3.2.5.)

      Received-Date            (OPTIONAL)

                This field is also called Delivery date.    This  field
                may  be  added  to a message by the recipient's message
                receiving program.  It indicates when the message  left




                                     20

                                                          Section 3.1.5

                the delivery system and entered the recipient's message
                processing domain.

      Start-Date               (OPTIONAL)

                This  field  contains the date on which a message takes
                effect.  (See also Section 3.2.5.)

      Warning-Date             (OPTIONAL)

                This field is used either alone or in conjunction  with
                an  End-Date  field.    It  contains one or more dates.
                These dates could  be  used  by  a  message  processing
                program  as  warnings of an impending end-date or other
                event.  (See also Section 3.2.5.)


      3.1.6  Cross-reference fields


           Cross-reference fields can be used to identify a message and
      to provide cross-references to  other  messages.    (See  Section
      3.2.4.)

      In-Reply-To              (OPTIONAL)

                This  field designates previous correspondence to which
                this message is a reply.  The usual  contents  of  this
                field  would be the contents of the Message-ID field of
                the message(s) being replied to.

      Message-ID               (OPTIONAL)

                This field contains a unique identifier for a  message.
                This  identifier is intended for machine generation and
                processing.   Further  definition  appears  in  Section
                3.2.4.1.    Only one Message-ID field is permitted in a
                message.

      Obsoletes                (OPTIONAL)

                This field identifies one or more  messages  that  this
                one replaces.

      Originator-Serial-Number (OPTIONAL)

                This field contains one or more serial numbers assigned
                by  the  message's  originator.  Messages with multiple
                recipients  should  have  the   same   value   in   the
                Originator-Serial-Number field.





                                     21

                                                          Section 3.1.6

      References               (OPTIONAL)

                This  field  identifies  other correspondence that this
                message  references.    If  the  other   correspondence
                contains  a  Message-ID  field,  the  contents  of  the
                References field must be the message identifier.


      3.1.7  Message-handling fields


           Message-handling fields describe aspects of how a message is
      to be handled or categorized.

      Precedence               (OPTIONAL)

                This  field  indicates  the  precedence  at  which  the
                message  was posted.  Ordinarily, message precedence or
                priority is a service request  to  a  message  transfer
                system.    A  message  originator, however, can include
                precedence information in a message.   One  example  of
                precedence  categories  are  those  used  by  the  U.S.
                Military: "ROUTINE,"  "PRIORITY,"  "IMMEDIATE,"  "FLASH
                OVERRIDE,"  and "EMERGENCY COMMAND PRECEDENCE."

      Message-Class            (OPTIONAL)

                This  field  indicates  the  purpose of a message.  For
                example, it might contain values  indicating  that  the
                                                             1
                message is a memorandum or a data-base entry. 

      Reissue-Type             (OPTIONAL)

                This   field   is  used  in  conjunction  with  message
                encapsulating  (see  Section  3.2.2)  to  differentiate
                between messages being assigned or redistributed.

      Received-From            (OPTIONAL)

                This  field  contains  a  record  of  a  message's path
                through   a   message    transfer    system.        The
                recipient's  message receiving program could store here
                any information about the  transfer  that  it  obtained
                from a message transfer system.
      _______________

        1
         The message format specification is not intended to be used as
      a  specification  for  exchanging  data-base  records.  Messages,
      however, sometimes contain data from or for a database.




                                     22

                                                          Section 3.1.7

      3.1.8  Message-content fields


           The   intent   of  most  messages  is  to  communicate  some
      particular information from originator  to  recipient.    Several
      fields in a message are designed to contain that information.

      Subject                  (BASIC)

                This  field  contains  any  information  the originator
                provided to summarize or indicate  the  nature  of  the
                message.

      Text                     (BASIC)

                This field contains the primary content of the message.

      Attachments              (OPTIONAL)

                This  field  contains  additional  data  accompanying a
                message.  It is similar in intent to  enclosures  in  a
                conventional mail system.

      Comments                 (OPTIONAL)

                This  field  permits  adding  comments  to  the message
                without  disturbing  the  original  contents   of   the
                message.

      Keywords                 (OPTIONAL)

                This  field  contains  keywords  or  phrases for use in
                retrieving a message.


      3.1.9  Extensions


           This message  format  specification  allows  two  additional
      types  of  fields,  vendor-defined  fields  and  as-yet-undefined
      (extension) fields that will be introduced by extensions to  this
      message format specification.


      vendor-defined-field
                Any  field  not defined in this message format specifi-
                cation or any extension or successor to it is a vendor-
                defined field.  Names for vendor-defined  fields  could
                be  preempted  by  extensions  to  this  message format
                specification.





                                     23

                                                          Section 3.1.9

      extension-field
                Any  field that is defined in a document published as a
                formal extension or replacement to this message  format
                specification.



      3.2  Message Processing Functions


           A  CBMS  provides three basic classes of functions: creating
      messages, transmitting messages to  their  recipient,  and  post-
      receipt  processing.    Although the message format specification
      does not define the number or nature of user functions in  CBMSs,
      the  meanings  for  the  fields  clearly  assume certain kinds of
      functions.  For example, fields specifying recipients of  replies
      to messages assume some kind of reply function; fields specifying
      message life span assume some kind of date processing functions.

           This  section  provides  more  detail on the processing that
      might be done by these kinds of functions, discussing the message
      fields that would be used and how  they  would  be  used.    (See
      summary in Table 1.)



      Processing Function    Fields Involved

      Message creation       Author, From, Sender, To,
        and posting