SMTP Service Extension for Message Tracking
RFC 3885
Document | Type |
RFC - Proposed Standard
(September 2004; No errata)
Updates RFC 3461
|
|
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Authors | Tony Hansen , Eric Allman | ||
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 ]Show full document text