    Network Working Group                                         S. Sluizer
    Request for Comments: 785                                      J. Postel
                                                                         ISI
                                                                   July 1981

                            MAIL TRANSFER PROTOCOL:
                          ISI TOPS20 FILE DEFINITIONS

    INTRODUCTION

       This document defines the ISI TOPS20s interface between the Mail
       Transfer Protocol (MTP) and a mail creation system (e.g., MM, HERMES,
       etc.) in terms of the files which implement it.  The internal
       structure and name of each file is described below.

       For a complete understanding of the MTP protocol as well as the terms
       used within this document, see RFC 780, "Mail Transfer Protocol".

    DESCRIPTION

       For each piece of mail, the TOPS20 interface between a mail creation
       system and MTP is comprised of two files.  The first file must be
       named "^V[--UNSENT-MAIL-CONTROL--^V].MTP.-1", where "^V" represents
       the character "control V" (ASCII code 026) and the generation number
       "-1" indicates the next higher generation number (at the time of the
       file's creation).  It is strongly suggested that the second file be
       named "^V[--UNSENT-MAIL-FILE--^V].MTP.-1", where "^V" and "-1" are as
       defined before.  (However, the actual file name may be chosen by the
       mail creation system.)  Both these files reside in the directory of
       the user who created the mail (as is currently the case with the
       MAILER-based system).

       "^V[--UNSENT-MAIL-CONTROL--^V].MTP.-1" is the control file.  It is an
       ASCIZ file and contains all information necessary to relay the mail
       through MTP.  It consists of a pointer to the mail text, the
       source-path, and all destination-paths.

       First is "FILE:" followed by the FULL mail text file name (which must
       include directory name and generation number) followed by <CRLF>
       (ASCII code 15 followed by ASCII code 12).  Note that a structure
       name is allowed; if not given "PS:" will be assumed.  Also note that
       for each character that must be quoted in a file name the quote
       character (^V) must be present in the string following "FILE:".  Next
       is "FROM:" followed by the <FROM-path> followed by <CRLF>.  Finally,
       each destination is given in the form "TO:" followed by the <TO-path>
       followed by <CRLF>.  The FROM- and TO-paths include surrounding angle
       brackets (i.e., <...>) and are identical respectively to the source-
       and destination-paths described in RFC 780.

    Sluizer & Postel                                                Page [1]

    July 1981                                                        RFC 785
    ISI TOPS20 File Definitions

      ---------------------------------------------------------------------
                           +------------------------+
                           |FILE: <File name> <CRLF>|
                           +------------------------+
                           |FROM: <FROM-path> <CRLF>|
                           +------------------------+
                           |  TO: <TO-path> <CRLF>  |
                           +------------------------+
                           |           ...          |
                           +------------------------+
                           |  TO: <TO-path> <CRLF>  |
                           +------------------------+

            File structure for ^V[--UNSENT-MAIL-CONTROL--^V].MTP.-1
                                    Figure 1
      ---------------------------------------------------------------------

       "^V[--UNSENT-MAIL-FILE--^V].MTP.-1" is the mail text file.  (Note
       that this is the file to which <File name> in the control file
       refers.)  It is mail which conforms to the standard described in RFC
       733, "Standard for the Format of ARPA Network Text Messages".

    DISCUSSION

       The older mail creation systems create N copies of a mail text file,
       one for each of the N addresses in the TO, CC, and BCC fields.  Each
       file is named "^V[--UNSENT-MAIL--^V].<mailbox>^V@<host>.-1", where
       <mailbox> and <host> are as defined in MTP, and "^V" and "-1" are as
       defined above.

       The interface between the mail creation system and MTP requires only
       the creation of two files, regardless of the number of addresses in
       the TO, CC, and BCC fields.  The control file contains the
       source-path and destination-paths information as well as a pointer to
       the mail text file.  The mail text file contains the the RFC 733
       header and body.

    Page [2]                                                Sluizer & Postel

    RFC 785                                                        July 1981
                                                      Mail Transfer Protocol

    EXAMPLE

       In this example, there were no previously existing versions of either
       the control file or the mail text file in directory <LINDA> where the
       message was created.  Figure 2 shows the mail text file and figure 3
       shows the control file.

       ------------------------------------------------------------------
          DATE: April 6, 1981
          Sender: Linda at ISIF
          From: Jon Postel <postel@isif>
          To: DCrocker at UDel, Cerf at ISIA
          Cc: postel@ISIF
          Bcc: sluizer@isif
          Subject: MTP discussion

          Your comments on the MTP document were most helpful.  A revised
          version will be forthcoming shortly.

          Thanks again,
          --jon

            File contents of <LINDA>^V[--UNSENT-MAIL-FILE--^V].MTP.1
                                    Figure 2
       ------------------------------------------------------------------

       ------------------------------------------------------------------
              +--------------------------------------------------+
              |FILE:<LINDA>^V[--UNSENT-MAIL-FILE--^V].MTP.1<CRLF>|
              +--------------------------------------------------+
              |FROM:<Linda@ISIF><CRLF>                           |
              +--------------------------------------------------+
              |TO:<DCrocker@UDel><CRLF>                          |
              +--------------------------------------------------+
              |TO:<Cerf@ISIA><CRLF>                              |
              +--------------------------------------------------+
              |TO:<postel@ISIF><CRLF>                            |
              +--------------------------------------------------+
              |TO:<sluizer@isif><CRLF>                           |
              +--------------------------------------------------+

              File contents of ^V[--UNSENT-MAIL-CONTROL--^V].MTP.1
                                    Figure 3
       ------------------------------------------------------------------

    Sluizer & Postel                                                Page [3]