Mail Transfer Protocol: ISI TOPS20 file definitions
The file formats for ISI TOPS-20's MTP mail system.
Sluizer, S. and J. Postel, "Mail Transfer Protocol: ISI TOPS20 file definitions", RFC 785, DOI 10.17487/RFC0785, July 1981, <https://www.rfc-editor.org/info/rfc785>.
@misc{rfc785,
series = {Request for Comments},
number = 785,
howpublished = {RFC 785},
publisher = {RFC Editor},
doi = {10.17487/RFC0785},
url = {https://www.rfc-editor.org/info/rfc785},
author = {S. Sluizer and J. Postel},
title = {{Mail Transfer Protocol: ISI TOPS20 file definitions}},
pagetotal = 3,
year = 1981,
month = jul,
} RFC text
Contents
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]
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
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]
AI ELI5
On this page
§1Introduction
RFC 785 defines the file interface between mail creation systems (such as MM or HERMES) and the Mail Transfer Protocol (MTP) on ISI's TOPS-20 system. It describes the file structures and naming conventions that allow these systems to exchange outgoing mail.
This memo describes how mail-writing programs talk to mail-sending programs using files on the TOPS-20 computer.
§2Control and Mail Files
The interface uses two files per message. The control file, named ^V[--UNSENT-MAIL-CONTROL--^V].MTP.-1, is an ASCII text file containing routing information: a FILE: line pointing to the mail text file, a FROM: line with the source address, and one or more TO: lines with destination addresses. The mail file contains the message headers and body conforming to RFC 733 format.
This two-file structure replaces the earlier method where mail creation systems created one separate file for each recipient, named with the mailbox and host of that recipient.
The control file is like a delivery label listing all the addresses, and the mail file is the actual letter. Both point to each other.
§3Addressing and Paths
Source and destination paths in the control file use angle brackets and are identical to the paths described in the MTP specification (RFC 780). The path format includes all routing information needed for MTP to relay the message to its destinations. Both the source address and all destination addresses are specified in a single control file, regardless of how many recipients the message has.
Addresses are written with angle brackets, like <person@computer>, and MTP knows how to deliver to each one listed in the control file.