SMTP Service Extension for Message Tracking
RFC 3885
| Document | Type |
RFC - Proposed Standard
(September 2004; No errata)
Updates RFC 3461
|
|
|---|---|---|---|
| Last updated | 2015-10-14 | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 3885 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Scott Hollenbeck | ||
| Send notices to | (None) | ||
Network Working Group E. Allman
Request for Comments: 3885 Sendmail, Inc.
Updates: 3461 T. Hansen
Category: Standards Track AT&T Laboratories
September 2004
SMTP Service Extension
for Message Tracking
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2004).
Abstract
This memo defines an extension to the SMTP service whereby a client
may mark a message for future tracking.
1. Other Documents and Conformance
The model used for Message Tracking is described in [RFC-MTRK-MODEL].
Doing a Message Tracking query is intended as a "last resort"
mechanism. Normally, Delivery Status Notifications (DSNs) [RFC-DSN-
SMTP] and Message Disposition Notifications (MDNs) [RFC-MDN] would
provide the primary delivery status. Only if the message is not
received, or there is no response from either of these mechanisms
should a Message Tracking query be issued.
The definition of the base64 token is imported from section 6.8 of
[RFC-MIME]. Formally,
base64 = %x2b / %x2f / %x30-39 / %x41-5a / %x61-7a
Allman & Hansen Standards Track [Page 1]
RFC 3885 Message Tracking ESMTP Extension September 2004
The definition of the DIGIT token is imported from [RFC-MSGFMT].
Formally,
DIGIT = %x30-39
Syntax notation in this document conforms to [RFC-ABNF].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14, RFC 2119
[RFC-KEYWORDS].
2. SMTP Extension Overview
The Message Tracking SMTP service extension uses the SMTP service
extension mechanism described in [RFC-ESMTP]. The following service
extension is hereby defined:
(1) The name of the SMTP service extension is "Message Tracking".
(2) The EHLO keyword value associated with this extension is
"MTRK".
(3) No parameters are allowed with this EHLO keyword value. Future
documents may extend this specification by specifying
parameters to this keyword value.
(4) One optional parameter using the keyword "MTRK" is added to the
MAIL command. In addition, the ENVID parameter of the MAIL
command (as defined in RFC 3461) MUST be supported, with
extensions as described below. The ORCPT parameter of the RCPT
command (as defined in RFC 3461) MUST also be supported. All
semantics associated with ENVID and ORCPT described in RFC 3461
MUST be supported as part of this extension.
(5) The maximum length of a MAIL command line is increased by 40
characters by the possible addition of the MTRK keyword and
value. Note that the 507 character extension of RCPT commands
for the ORCPT parameter and the 107 character extension of MAIL
commands for the ENVID parameter as mandated by RFC 3461 [RFC-
DSN-SMTP] must also be included.
(6) No SMTP verbs are defined by this extension.
Allman & Hansen Standards Track [Page 2]
RFC 3885 Message Tracking ESMTP Extension September 2004
3. The Extended MAIL Command
The extended MAIL command is issued by an SMTP client when it wishes
to inform an SMTP server that message tracking information should be
retained for future querying. The extended MAIL command is identical
to the MAIL command as defined in [RFC-SMTP], except that MTRK,
ORCPT, and ENVID parameters appear after the address.
3.1. The MTRK parameter to the ESMTP MAIL command
Any sender wishing to request the retention of data for further
tracking of message must first tag that message as trackable by
creating two values A and B:
A = some-large-random-number
B = SHA1(A)
The large random number A is calculated on a host-dependent basis.
See [RFC-RANDOM] for a discussion of choosing good random numbers.
This random number MUST be at least 128 bits but MUST NOT be more
than 1024 bits.
The 128-bit hash B of A is then computed using the SHA-1 algorithm as
described in [NIST-SHA1].
The sender then base64 encodes value B and passes that value as the
mtrk-certifier on the MAIL command:
mtrk-parameter = "MTRK=" mtrk-certifier [ ":" mtrk-timeout ]
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