From owner-ietf-msgtrk@mail.imc.org Mon Jun 18 23:22:54 2001 Received: from above.proper.com (above.proper.com [208.184.76.39]) by ietf.org (8.9.1a/8.9.1a) with ESMTP id XAA29233 for ; Mon, 18 Jun 2001 23:22:53 -0400 (EDT) Received: from localhost (localhost [[UNIX: localhost]]) by above.proper.com (8.11.3/8.11.3) id f5J3IXU23670 for ietf-msgtrk-bks; Mon, 18 Jun 2001 20:18:33 -0700 (PDT) Received: from knecht.Neophilic.COM (knecht.sendmail.org [209.31.233.176]) by above.proper.com (8.11.3/8.11.3) with ESMTP id f5J3IVJ23665 for ; Mon, 18 Jun 2001 20:18:31 -0700 (PDT) Received: from knecht.Neophilic.COM (localhost.Neophilic.COM [127.0.0.1]) by knecht.Neophilic.COM (8.12.0.Beta12/8.12.0.Beta12) with ESMTP id f5J3Ia2U017373; Mon, 18 Jun 2001 20:18:36 -0700 (PDT) Message-Id: <200106190318.f5J3Ia2U017373@knecht.Neophilic.COM> X-Mailer: exmh version 2.3.1 01/18/2001 with nmh-1.0.4 To: Chris Newman From: Eric Allman X-URL: http://WWW.Sendmail.ORG/~eric cc: Eric Allman , ietf-msgtrk@imc.org Subject: Re: I-D ACTION:draft-ietf-msgtrk-trkstat-01.txt In-reply-to: Mail from Chris Newman dated Thu, 05 Apr 2001 17:57:14 PDT <1772928.986493434@nifty-jr.west.sun.com> Date: Mon, 18 Jun 2001 20:18:36 -0700 Sender: owner-ietf-msgtrk@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: Chris, sorry for the long delay in replying -- I set this aside for a while, and am just getting back to it. The problem with using "expanded" for all cases where there are multiple recipients is that the MTA doesn't necessarily know. For example, if the MTA can deliver to a program on behalf of a user, that program might explode a mailing list. I believe you see this in Postfix, and for that matter some message stores (including, I believe, Exchange) have the property that the MTA delivers to a real mailbox which is then scanned later by a background process that does the exploding. I think this is the same reason that the wording in 1894 is fairly ambiguous. eric ============= In Reply To: =========================================== : From: Chris Newman : Subject: Re: I-D ACTION:draft-ietf-msgtrk-trkstat-01.txt : Date: Thu, 05 Apr 2001 17:57:14 -0700 : --On Thursday, April 5, 2001 17:21 -0700 Eric Allman : wrote: : > This wording was taken nearly as is from 1894, and the intent was to : > keep things fairly parallel to that spec. I'm open to suggestions. : > Anyone? : : My suggestion is to use "expanded" for _all_ cases where there are multiple : recipients. If a user sends to a list and gets a "delivered" notification, : their assumption will be that the message has been delivered to all list : recipients. So any use of "delivered" with a multiple recipients is likely : to result in a "user astonishment" scenario. Since those are bad, stick to : "expanded". : : The only caveat would be if a site has a local alias sent to multiple : recipients, and wishes to conceal the fact the address is a list. Then : "delivered" would be OK. : : > Already dealt with, as indicated in my previous message. Do you still : > think a cross-reference is warranted? : : A non-normative cross-reference would be nice. When I'm considering only : the security implications of a protocol, I look only at the security : considerations and anything it references. But the text you added is good : enough. : : - Chris : From owner-ietf-msgtrk@mail.imc.org Tue Jun 19 13:30:41 2001 Received: from above.proper.com (above.proper.com [208.184.76.39]) by ietf.org (8.9.1a/8.9.1a) with SMTP id NAA28114 for ; Tue, 19 Jun 2001 13:30:40 -0400 (EDT) Received: by above.proper.com (8.11.3/8.11.3) id f5JHROo20647 for ietf-msgtrk-bks; Tue, 19 Jun 2001 10:27:24 -0700 (PDT) Received: from netscape.com (c3po.netscape.com [205.217.237.46]) by above.proper.com (8.11.3/8.11.3) with ESMTP id f5JHRMJ20643 for ; Tue, 19 Jun 2001 10:27:23 -0700 (PDT) Received: from u-gotmail.red.iplanet.com (u-gotmail.red.iplanet.com [192.18.73.45]) by netscape.com (8.10.0/8.10.0) with ESMTP id f5JHRIY07057; Tue, 19 Jun 2001 10:27:18 -0700 (PDT) Received: from nifty-jr.west.sun.com (nifty-jr.West.Sun.COM [129.153.12.95]) by we-gotmail.red.iplanet.com (iPlanet Messaging Server 5.1 (built May 7 2001)) with ESMTP id <0GF600H3QTUU7N@we-gotmail.red.iplanet.com>; Tue, 19 Jun 2001 10:28:07 -0700 (PDT) Date: Tue, 19 Jun 2001 10:25:45 -0700 From: Chris Newman Subject: Re: I-D ACTION:draft-ietf-msgtrk-trkstat-01.txt In-reply-to: <200106190318.f5J3Ia2U017373@knecht.Neophilic.COM> To: Eric Allman Cc: ietf-msgtrk@imc.org Message-id: <3353953.992946345@nifty-jr.west.sun.com> MIME-version: 1.0 X-Mailer: Mulberry/2.1.0a6 (Mac OS/PPC) Content-type: text/plain; charset=us-ascii; format=flowed Content-transfer-encoding: 7BIT Content-disposition: inline References: <200106190318.f5J3Ia2U017373@knecht.Neophilic.COM> Sender: owner-ietf-msgtrk@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: Content-Transfer-Encoding: 7BIT --On Monday, June 18, 2001 20:18 -0700 Eric Allman wrote: > The problem with using "expanded" for all cases where there are > multiple recipients is that the MTA doesn't necessarily know. For > example, if the MTA can deliver to a program on behalf of a user, > that program might explode a mailing list. I believe you see this > in Postfix, and for that matter some message stores (including, I > believe, Exchange) have the property that the MTA delivers to a > real mailbox which is then scanned later by a background process > that does the exploding. I'm all for accepting reality. So I'd say that both "delivered" and "expanded" are valid for any multi-recipient scenario, although the latter should be preferred since it makes it clearer to the notification recipient what happened. It's fine to have overlapping meanings like this, but it needs to be explicit to avoid confusion. - Chris From owner-ietf-msgtrk@mail.imc.org Wed Jun 20 22:59:54 2001 Received: from above.proper.com (above.proper.com [208.184.76.39]) by ietf.org (8.9.1a/8.9.1a) with SMTP id WAA02309 for ; Wed, 20 Jun 2001 22:59:53 -0400 (EDT) Received: from localhost (localhost [[UNIX: localhost]]) by above.proper.com (8.11.3/8.11.3) id f5L2vRr14719 for ietf-msgtrk-bks; Wed, 20 Jun 2001 19:57:27 -0700 (PDT) Received: from knecht.Neophilic.COM (knecht.sendmail.org [209.31.233.176]) by above.proper.com (8.11.3/8.11.3) with ESMTP id f5L2vPk14715 for ; Wed, 20 Jun 2001 19:57:25 -0700 (PDT) Received: from knecht.Neophilic.COM (localhost.Neophilic.COM [127.0.0.1]) by knecht.Neophilic.COM (8.12.0.Beta12/8.12.0.Beta12) with ESMTP id f5L2vU2U040408; Wed, 20 Jun 2001 19:57:30 -0700 (PDT) Message-Id: <200106210257.f5L2vU2U040408@knecht.Neophilic.COM> X-Mailer: exmh version 2.3.1 01/18/2001 with nmh-1.0.4 To: Chris Newman From: Eric Allman X-URL: http://WWW.Sendmail.ORG/~eric cc: Eric Allman , ietf-msgtrk@imc.org Subject: Re: I-D ACTION:draft-ietf-msgtrk-trkstat-01.txt In-reply-to: Mail from Chris Newman dated Tue, 19 Jun 2001 10:25:45 PDT <3353953.992946345@nifty-jr.west.sun.com> Date: Wed, 20 Jun 2001 19:57:30 -0700 Sender: owner-ietf-msgtrk@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: OK, I've added the following paragraph after the list of possible actions: There may be some confusion between when to use .q expanded versus .q delivered . Whenever possible, .q expanded should be used when the MTA knows that the message will be sent to multiple addresses. However, in some cases the delivery occurs to a program which, unknown to the MTA, causes mailing list expansion; in the extreme case, the delivery may be to a real mailbox that has the side effect of list expansion. If the MTA cannot ensure that this delivery will cause list expansion, it should set the action to .q delivered . Does this adequately clarify things? eric ============= In Reply To: =========================================== : From: Chris Newman : Subject: Re: I-D ACTION:draft-ietf-msgtrk-trkstat-01.txt : Date: Tue, 19 Jun 2001 10:25:45 -0700 : --On Monday, June 18, 2001 20:18 -0700 Eric Allman : wrote: : > The problem with using "expanded" for all cases where there are : > multiple recipients is that the MTA doesn't necessarily know. For : > example, if the MTA can deliver to a program on behalf of a user, : > that program might explode a mailing list. I believe you see this : > in Postfix, and for that matter some message stores (including, I : > believe, Exchange) have the property that the MTA delivers to a : > real mailbox which is then scanned later by a background process : > that does the exploding. : : I'm all for accepting reality. So I'd say that both "delivered" and : "expanded" are valid for any multi-recipient scenario, although the latter : should be preferred since it makes it clearer to the notification recipient : what happened. It's fine to have overlapping meanings like this, but it : needs to be explicit to avoid confusion. : : - Chris : From owner-ietf-msgtrk@mail.imc.org Thu Jun 21 15:02:46 2001 Received: from above.proper.com (above.proper.com [208.184.76.39]) by ietf.org (8.9.1a/8.9.1a) with SMTP id PAA14336 for ; Thu, 21 Jun 2001 15:02:45 -0400 (EDT) Received: from localhost (localhost [[UNIX: localhost]]) by above.proper.com (8.11.3/8.11.3) id f5LJ11E11110 for ietf-msgtrk-bks; Thu, 21 Jun 2001 12:01:01 -0700 (PDT) Received: from netscape.com (c3po.netscape.com [205.217.237.46]) by above.proper.com (8.11.3/8.11.3) with ESMTP id f5LJ0xk11096 for ; Thu, 21 Jun 2001 12:00:59 -0700 (PDT) Received: from u-gotmail.red.iplanet.com (u-gotmail.red.iplanet.com [192.18.73.45]) by netscape.com (8.10.0/8.10.0) with ESMTP id f5LJ0tY21109; Thu, 21 Jun 2001 12:00:55 -0700 (PDT) Received: from nifty-jr.west.sun.com (nifty-jr.West.Sun.COM [129.153.12.95]) by we-gotmail.red.iplanet.com (iPlanet Messaging Server 5.1 (built May 7 2001)) with ESMTP id <0GFA00H9MNJ0R9@we-gotmail.red.iplanet.com>; Thu, 21 Jun 2001 12:01:48 -0700 (PDT) Date: Thu, 21 Jun 2001 11:59:19 -0700 From: Chris Newman Subject: Re: I-D ACTION:draft-ietf-msgtrk-trkstat-01.txt In-reply-to: <200106210257.f5L2vU2U040408@knecht.Neophilic.COM> To: Eric Allman Cc: ietf-msgtrk@imc.org Message-id: <7442996.993124759@nifty-jr.west.sun.com> MIME-version: 1.0 X-Mailer: Mulberry/2.1.0a6 (Mac OS/PPC) Content-type: text/plain; charset=us-ascii; format=flowed Content-transfer-encoding: 7BIT Content-disposition: inline References: <200106210257.f5L2vU2U040408@knecht.Neophilic.COM> Sender: owner-ietf-msgtrk@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: Content-Transfer-Encoding: 7BIT --On Wednesday, June 20, 2001 19:57 -0700 Eric Allman wrote: > OK, I've added the following paragraph after the list of possible actions: > > There may be some confusion between when to use > .q expanded > versus > .q delivered . > Whenever possible, > .q expanded > should be used when the MTA knows that the message will be sent to > multiple addresses. > However, in some cases the delivery occurs to a program > which, unknown to the MTA, causes mailing list expansion; > in the extreme case, the delivery may be to a real mailbox > that has the side effect of list expansion. > If the MTA cannot ensure that this delivery will cause list expansion, > it should set the action to > .q delivered . > > Does this adequately clarify things? Sounds good to me. - Chris From owner-ietf-msgtrk@mail.imc.org Thu Jun 21 21:16:18 2001 Received: from above.proper.com (above.proper.com [208.184.76.39]) by ietf.org (8.9.1a/8.9.1a) with SMTP id VAA22982 for ; Thu, 21 Jun 2001 21:16:17 -0400 (EDT) Received: from localhost (localhost [[UNIX: localhost]]) by above.proper.com (8.11.3/8.11.3) id f5M1BX119128 for ietf-msgtrk-bks; Thu, 21 Jun 2001 18:11:33 -0700 (PDT) Received: from knecht.Neophilic.COM (knecht.sendmail.org [209.31.233.176]) by above.proper.com (8.11.3/8.11.3) with ESMTP id f5M1BUk19123 for ; Thu, 21 Jun 2001 18:11:30 -0700 (PDT) Received: from knecht.Neophilic.COM (localhost.Neophilic.COM [127.0.0.1]) by knecht.Neophilic.COM (8.12.0.Beta12/8.12.0.Beta12) with ESMTP id f5M1BYJv051179 for ; Thu, 21 Jun 2001 18:11:34 -0700 (PDT) Message-Id: <200106220111.f5M1BYJv051179@knecht.Neophilic.COM> X-Mailer: exmh version 2.3.1 01/18/2001 with nmh-1.0.4 To: ietf-msgtrk@imc.org From: Eric Allman X-URL: http://WWW.Sendmail.ORG/~eric Subject: soon-to-be-submitted msgtrk drafts Mime-Version: 1.0 Content-Type: multipart/mixed ; boundary="==_Exmh_-10955732860" Date: Thu, 21 Jun 2001 18:11:34 -0700 Sender: owner-ietf-msgtrk@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: This is a multipart MIME message. --==_Exmh_-10955732860 Content-Type: text/plain Enclosed are the two updated drafts that I believe contain all the comments I've received to date. I want to submit these "soon", but I thought I would give folks here one last look-see. eric --==_Exmh_-10955732860 Content-Type: text/plain ; name="draft-ietf-msgtrk-smtpext.txt" Content-Description: draft-ietf-msgtrk-smtpext.txt Content-Disposition: attachment; filename="draft-ietf-msgtrk-smtpext.txt" Internet Draft E. Allman draft-ietf-msgtrk-smtpext-02.txt Sendmail, Inc. Valid for six months T. Hansen Updates: RFC 1891 AT&T Laboratories June 21, 2001 SMTP Service Extension for Message Tracking Status of This Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also dis- tribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at: http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at: http://www.ietf.org/shadow.html This document is a submission by the MSGTRK Working Group of the Internet Engineering Task Force (IETF). Comments should be submitted to the ietf-msgtrk@imc.org mailing list. An archive of the mailing list may be found at http://www.imc.org/ietf-msgtrk/index.html Distribution of this memo is unlimited. 1. Abstract This memo defines an extension to the SMTP service whereby a client may mark a message for future tracking. Internet Draft Message Tracking ESMTP Extension June 21, 2001 2. Other Documents and Conformance The model used for Message Tracking is described in [DRAFT- 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 mecha- nisms should a Message Tracking query be issued. The definition of the base64 token is imported from section 6.8 of [RFC-MIME]. 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 RFC 2119 [RFC-KEYWORDS]. 3. SMTP Extension Overview The Message Tracking SMTP service extension uses the SMTP ser- vice extension mechanism described in [RFC-ESMTP]. The following service extension is hereby defined: (1) The name of the SMTP service extension is "Message Track- ing". (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 options. (4) One optional parameter using the keyword "MTRK" is added to the MAIL FROM command. In addition, the ENVID and ORCPT parameters (as defined in RFC 1891 sections 5.4 and 5.2 respectively) MUST be supported, with extensions as described below. (5) The maximum length of a MAIL FROM command line is increased by 40 characters by the possible addition of the MTRK key- word and value. Note that a further extension of 614 char- acters for the ORCPT and ENVID parameters is required by [RFC-DSN-EXT]. (6) No SMTP verbs are defined by this extension. Allman & Hansen [Page 2] Internet Draft Message Tracking ESMTP Extension June 21, 2001 4. The Extended MAIL FROM Command The extended MAIL FROM 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 FROM command is identical to the MAIL FROM command as defined in [RFC-SMTP], except that MTRK, ORCPT, and ENVID parameters appear after the address. 4.1. The MTRK parameter to the ESMTP MAIL command Any sender wishing to track a 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 ran- dom 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 FROM command: mtrk-parameter = "MTRK=" mtrk-certifier [ ":" mtrk-timeout ] mtrk-certifier = base64 ; authenticator mtrk-timeout = 1*9digit ; seconds until timeout A is stored in the originator's tracking database to vali- date future tracking requests as described in [DRAFT-MTRK-MTQP]. B is stored in tracking databases of compliant MTAs and used to authenticate future tracking requests. The mtrk-timeout field indicates the number of seconds that the client requests that this tracking information be retained on intermediate servers, as measured from the initial receipt of the message at that server. Servers MAY ignore this value if it violates local policy. In particular, servers MAY silently enforce an upper limit to how long they will retain tracking data; this limit MUST be at least one day. If no mtrk-timeout field is specified then the server should use a local default. This default SHOULD be 8-10 days and MUST be at least one day. Notwithstanding this clause, the information MUST NOT be expired while the message remains in the queue for this server: that is, an MTQP server MUST NOT deny knowledge of a message while that same message sits in the MTA queue. If the message is relayed to another compliant SMTP server, the MTA acting as the client SHOULD pass an mtrk-timeout field Allman & Hansen [Page 3] Internet Draft Message Tracking ESMTP Extension June 21, 2001 equal to the remaining life of that message tracking informa- tion. Specifically, the tracking timeout is decremented by the number of seconds the message has lingered at this MTA and then passed to the next MTA. If the decremented tracking timeout is less than or equal to zero, the entire MTRK parameter MUST NOT be passed to the next MTA; essentially, the entire tracking path is considered to be lost at that point. See [RFC-DELIVERYBY] section 4 for an explanation of why a timeout is used instead of an absolute time. 4.2. Use of ENVID To function properly, Message Tracking requires that each message have a unique identifier that is never reused by any other message. For that purpose, if the MTRK parameter is given, an ENVID parameter MUST be included, and the syntax of ENVID from RFC 1891 section 5.4 is extended as follows: envid-parameter = "ENVID=" unique-envid unique-envid = local-envid "@" fqhn local-envid = xtext fqhn = xtext The unique-envid MUST be chosen in such a way that the same ENVID will never be used by any other message sent from this system or any other system. In most cases, this means setting fqhn to be the fully qualified host name of the system generat- ing this ENVID, and local-envid to an identifier that is never re-used by that host. Any resubmissions of this message into the message trans- mission system MUST assign a new ENVID. In this context, "resubmission" includes forwarding or resending a message from a user agent, but does not include MTA-level aliasing or forward- ing where the message does not leave and re-enter the message transmission system. 4.3. Forwarding Tracking Certifiers MTAs SHOULD forward unexpired tracking certifiers to com- pliant mailers as the mail is transferred during regular hop-to- hop transfers. If the "downstream" MTA is not MTRK-compliant, then the MTRK= parameter MUST be deleted. If the downstream MTA is DSN-compliant, then the ENVID and ORCPT parameters MUST NOT be deleted. If aliasing, forwarding, or other redirection of messages to a single recipient occurs, then the MTA SHOULD treat this as an ordinary hop-to-hop transfer and forward the MTRK=, ENVID=, and ORCPT= values; these values MUST NOT be modified. MTAs MUST NOT copy MTRK certifiers when relaying a message to multiple recipients. An MTA MAY designate one recipient in a multi-recipient alias as the "primary" recipient to which track- ing requests shall be forwarded; other addresses SHALL NOT Allman & Hansen [Page 4] Internet Draft Message Tracking ESMTP Extension June 21, 2001 receive tracking certifiers. MTAs MUST NOT forward MTRK certi- fiers when doing mailing list expansion. 5. Security Issues 5.1. Denial of service An attacker could attempt to flood the database of a server by submitting large numbers of small, tracked messages. In this case, a site may elect to lower its maximum retention period retroactively. 5.2. Confidentiality The mtrk-authenticator value (``A'') must be hard to pre- dict and not reused. The originating client must take reasonable precautions to protect the secret. For example, if the secret is stored in a message store (e.g., a "Sent" folder), the client must make sure the secret isn't accessible by attackers, particularly on a shared store. Many site administrators believe that concealing names and topologies of internal systems and networks is an important security feature. MTAs need to balance such desires with the need to provide adequate tracking information. In some cases site administrators may want to treat deliv- ery to an alias as final delivery in order to separate roles from individuals. For example, sites implementing ``postmas- ter'' or ``webmaster'' as aliases may not wish to expose the identity of those individuals by permitting tracking through those aliases. In other cases, providing the tracking informa- tion for an alias is important, such as when the alias points to the user's preferred public address. 6. References [DRAFT-MTRK-MODEL] T. Hansen, ``Message Tracking Model and Requirements.'' draft-ietf-msgtrk-model-03.txt. November 2000. [DRAFT-MTRK-MTQP] T. Hansen, ``Message Tracking Query Protocol.'' draft-ietf- msgtrk-mtqp-01.txt. November 2000. [RFC-ABNF] Crocker, D., Editor, and P. Overell, ``Augmented BNF for Syn- tax Specifications: ABNF'', RFC 2234, November 1997. [RFC-DELIVERYBY] D. Newman, ``Deliver By SMTP Service Extension.'' RFC 2852. June 2000. Allman & Hansen [Page 5] Internet Draft Message Tracking ESMTP Extension June 21, 2001 [RFC-DSN-REPT] G. Vaudreuil, ``The Multipart/Report Content Type for the Reporting of Mail System Administrative Messages.'' RFC 1892. January 1996. [RFC-DSN-SMTP] K. Moore, ``SMTP Service Extension for Delivery Status Notifi- cations.'' RFC 1891. January 1996. [RFC-DSN-STAT] K. Moore and G. Vaudreuil, ``An Extensible Message Format for Delivery Status Notifications.'' RFC 1894. January 1996. [RFC-EMSSC] G. Vaudreuil, ``Enhanced Mail System Status Codes.'' RFC 1893. January 1996. [RFC-ESMTP] Rose, M., Stefferud, E., Crocker, D., Klensin, J. and N. Freed, ``SMTP Service Extensions.'' STD 10, RFC 1869. Novem- ber 1995. [RFC-KEYWORDS] S. Bradner, ``Key words for use in RFCs to Indicate Require- ment Levels.'' RFC 2119. March 1997. [RFC-MDN] R. Fajman, ``An Extensible Message Format for Message Disposi- tion Notifications.'' RFC 2298. March 1998. [RFC-MIME] N. Freed and N. Borenstein, ``Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bod- ies.'' RFC 2045. November 1996. [RFC-MSGFMT] D. Crocker, ``Standard for the Format of ARPA Internet Text Messages.'' RFC 822. August 1982. [RFC-RANDOM] D. Eastlake, S. Crocker, and J. Schiller, ``Randomness Recom- mendations for Security.'' RFC 1750. December 1994. [RFC-RELATED] E. Levinson, ``The MIME Multipart/Related Content-type.'' RFC 2387. August 1998. [NIST-SHA1] NIST FIPS PUB 180-1, ``Secure Hash Standard.'' National Institute of Standards and Technology, U.S. Department of Com- merce. May 1994. DRAFT. [RFC-SMTP] J. Postel, ``Simple Mail Transport Protocol.'' RFC 821. August 1982. Allman & Hansen [Page 6] Internet Draft Message Tracking ESMTP Extension June 21, 2001 7. Authors' Addresses Eric Allman Sendmail, Inc. 6603 Shellmound Emeryville, CA 94608 U.S.A. E-Mail: eric@Sendmail.COM Phone: +1 510 594 5501 Fax: +1 510 594 5411 Tony Hansen AT&T Laboratories Lincroft, NJ 07738 U.S.A. Phone: +1 732 576 3207 E-Mail: tony@att.com Allman & Hansen [Page 7] --==_Exmh_-10955732860 Content-Type: text/plain ; name="draft-ietf-msgtrk-trkstat.txt" Content-Description: draft-ietf-msgtrk-trkstat.txt Content-Disposition: attachment; filename="draft-ietf-msgtrk-trkstat.txt" Internet Draft E. Allman draft-ietf-msgtrk-trkstat-02.txt Sendmail, Inc. Valid for six months June 21, 2001 Updates: RFC 1893 The Message/Tracking-Status MIME Extension Status of This Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also dis- tribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at: http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at: http://www.ietf.org/shadow.html This document is a submission by the MSGTRK Working Group of the Internet Engineering Task Force (IETF). Comments should be submitted to the ietf-msgtrk@imc.org mailing list. An archive of the mailing list may be found at http://www.imc.org/ietf-msgtrk/index.html Distribution of this memo is unlimited. 1. Abstract Message Tracking is expected to be used to determine the sta- tus of undelivered e-mail upon request. Tracking is used in con- junction with Delivery Status Notifications [RFC-DSN-SMTP] and Mes- sage Disposition Notifications [RFC-MDN]; generally, a message tracking request will be issued only when a DSN or MDN has not been received within a reasonable timeout period. This memo defines a MIME [RFC-MIME] content-type for message tracking status in the same spirit as RFC 1894, ``An Extensible Message Format for Delivery Status Notifications'' [RFC-DSN-STAT]. Internet Draft Message/Tracking-Status June 21, 2001 It is to be issued upon a request as described in ``Message Track- ing Query Protocol'' [DRAFT-MTRK-MTQP]. This memo defines only the format of the status information. An extension to SMTP [RFC-ESMTP] to label messages for further tracking and request tracking status is defined in a separate memo [DRAFT-MTRK-SMTPEXT]. 2. Other Documents and Conformance The model used for Message Tracking is described in [DRAFT- MTRK-MODEL]. Message tracking is intended for use as a "last resort" mecha- nism. Normally, Delivery Status Notifications (DSNs) [RFC-DSN- SMTP] and Message Disposition Notifications (MDNs) [RFC-MDN] would provide the primary delivery status. Only if no response is received from either of these mechanisms would Message Tracking be used. This document is based on [RFC-DSN-STAT]. Sections 1.3 (Ter- minology), 2.1.1 (General conventions for DSN fields), 2.1.2 ("*-type" subfields), and 2.1.3 (Lexical tokens imported from RFC 822) of [RFC-DSN-STAT] are included into this document by refer- ence. Other sections are further incorporated as described herein. Syntax notation in this document conforms to [RFC-ABNF]. The following lexical tokens, defined in [RFC-MSGFMT], are used in the ABNF grammar for MTSNs: atom, CHAR, comment, CR, CRLF, DIGIT, LF, linear-white-space, SPACE, text. The date-time lexical token is defined in [RFC-HOSTREQ]. 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 RFC 2119 [RFC-KEYWORDS]. 3. Format of a Message Tracking Status Notification A Message Tracking Status Notification (MTSN) is intended to be returned as the body of a Message Tracking request [DRAFT-MTRK- MTQP]. The actual body MUST be a multipart/related [RFC-RELATED] with type parameter of "message/tracking-status"; each subpart MUST be type "message/tracking-status" as described herein. 3.1. The message/tracking-status content-type The message/tracking-status content-type is defined as fol- lows: Allman [Page 2] Internet Draft Message/Tracking-Status June 21, 2001 MIME type name: message MIME subtype name: tracking-status Optional parameters: none Encoding considerations: "7bit" encoding is sufficient and MUST be used to maintain readability when viewed by non-MIME mail readers. Security considerations: discussed in section 4 of this memo. The body of a message/tracking-status is modeled after [RFC-DSN-STAT]. That body consists of one or more "fields" for- matted to according to the ABNF of RFC 822 header "fields" (see [RFC-MSGFMT]). The per-message fields appear first, followed by a blank line. Following the per-message fields are one or more groups of per-recipient fields. Each group of per-recipient fields is preceded by a blank line. Note that there will be a blank line between the final per-recipient field and the MIME boundary, since one CRLF is necessary to terminate the field, and a second is necessary to introduce the MIME boundary. For- mally, the syntax of the message/tracking-status content is as follows: tracking-status-content = per-message-fields 1*( CRLF per-recipient-fields ) The per-message fields are described in section 3.2. The per- recipient fields are described in section 3.3. 3.1.1. General conventions for MTSN fields Section 2.1.1 (General conventions for DSN fields) of [RFC-DSN-STAT] is included herein by reference. Notably, the definition of xtext is identical to that of that document. 3.1.2. *-type subfields Section 2.1.2 (*-type subfields) of [RFC-DSN-STAT] is included herein by reference. Notably, the definitions of address-type, diagnostic-type, and MTA-name type are identi- cal to that of RFC 1894. 3.2. Per-Message MTSN Fields Some fields of an MTSN apply to all of the addresses in a single envelope. These fields may appear at most once in any MTSN. These fields are used to correlate the MTSN with the original message transaction and to provide additional informa- tion which may be useful to gateways. per-message-fields = original-envelope-id-field CRLF reporting-mta-field CRLF arrival-date CRLF *( extension-field CRLF ) Allman [Page 3] Internet Draft Message/Tracking-Status June 21, 2001 3.2.1. The Original-Envelope-Id field The optional Original-Envelope-Id field is defined as in section 2.2.1 of [RFC-DSN-STAT]. This field is REQUIRED. 3.2.2. The Reporting-MTA field The Reporting-MTA field is defined as in section 2.2.2 of [RFC-DSN-STAT]. This field is REQUIRED. 3.2.3. The Arrival-Date field The Arrival-Date field is defined as in section 2.2.5 of [RFC-DSN-STAT]. This field is REQUIRED. 3.3. Per-Recipient MTSN fields An MTSN contains information about attempts to deliver a message to one or more recipients. The delivery information for any particular recipient is contained in a group of contiguous per-recipient fields. Each group of per-recipient fields is preceded by a blank line. The syntax for the group of per-recipient fields is as fol- lows: per-recipient-fields = original-recipient-field CRLF final-recipient-field CRLF action-field CRLF status-field CRLF [ remote-mta-field CRLF ] [ last-attempt-date-field CRLF ] [ will-retry-until-field CRLF ] *( extension-field CRLF ) 3.3.1. Original-Recipient field The optional Original-Recipient field is defined as in section 2.3.1 of [RFC-DSN-STAT]. This field is REQUIRED. 3.3.2. Final-Recipient field The required Final-Recipient field is defined as in sec- tion 2.3.2 of [RFC-DSN-STAT]. This field is REQUIRED. 3.3.3. Action field The required Action field indicates the action performed by the Reporting-MTA as a result of its attempt to deliver the message to this recipient address. This field MUST be present for each recipient named in the MTSN. The syntax is as defined in section 2.3.3 of RFC 1894. This field is REQUIRED. Allman [Page 4] Internet Draft Message/Tracking-Status June 21, 2001 Valid actions are: failed The message could not be delivered. If DSNs have been enabled, a "failed" DSN should already have been returned. delayed The message is currently waiting in the MTA queue for future delivery. Essentially, this action means "the message is located, and it is here." delivered The message has been successfully delivered to the final recipient. This includes "delivery" to a mailing list exploder. It does not indi- cate that the message has been read. No further information is available; in particular, the tracking agent SHOULD NOT attempt further "down- stream" tracking requests. expanded The message has been successfully delivered to the recipient address as specified by the sender, and forwarded by the Reporting-MTA beyond that destination to multiple additional recipient addresses. However, these additional addresses are not trackable, and the tracking agent SHOULD NOT attempt further "downstream" tracking requests. relayed The message has been delivered into an environ- ment that does not support message tracking. No further information is available; in particular, the tracking agent SHOULD NOT attempt further "downstream" tracking requests. transferred The message has been transferred to another MTRK-compliant MTA. The tracking agent SHOULD attempt further "downstream" tracking requests. opaque The message may or may not have been seen by this system. No further information is avail- able or forthcoming. There may be some confusion between when to use "expanded" versus "delivered". Whenever possible, "expanded" should be used when the MTA knows that the message will be sent to multiple addresses. However, in some cases the delivery occurs to a program which, unknown to the MTA, causes mailing list expansion; in the extreme case, the delivery may be to a real mailbox that has the side effect of list expansion. If the MTA cannot ensure that this delivery will cause list expansion, it should set the action to "delivered". Allman [Page 5] Internet Draft Message/Tracking-Status June 21, 2001 3.3.4. Status field The Status field is defined as in RFC 1894 section 2.3.4. A new code is added to RFC 1893 [RFC-EMSSC], "Enhanced Mail System Status Codes", X.1.9 Message relayed to non-compliant mailer" The mailbox address specified was valid, but the mes- sage has been relayed to a system that does not speak this protocol; no further information can be pro- vided. A 2.1.9 Status field MUST be used exclusively with a "relayed" Action field. This field is REQUIRED. 3.3.5. Remote-MTA field The Remote-MTA field is defined as in section Reference 2.3.5 of [RFC-DSN-STAT]. This field MUST NOT be included if no delivery attempts have been made or if the Action field has value "opaque". If delivery to some agent other than an MTA (for example, a Local Delivery Agent) then this field MAY be included, giving the name of the host on which that agent was contacted. 3.3.6. Last-Attempt-Date field The Last-Attempt-Date field is defined as in section Reference 2.3.7 of [RFC-DSN-STAT]. This field is REQUIRED if any delivery attempt has been made and the Action field does not have value "opaque", in which case it will specify when it last attempted to deliver this message to another MTA or other Delivery Agent. This field MUST NOT be included if no delivery attempts have been made. 3.3.7. Will-Retry-Until field The Will-Retry-Until field is defined as in section Ref- erence 2.3.8 of [RFC-DSN-STAT]. If the message is not in the local queue or the Action field has the value ``opaque'' the Will-Retry-Until field MUST NOT be included; otherwise, this field is REQUIRED. 3.4. Extension fields Future extension fields may be defined as defined in sec- tion 2.4 of [RFC-DSN-STAT]. 3.5. Interaction Between MTAs and LDAs A message that has been delivered to a Local Delivery Agent (LDA) that understands message tracking (in particular, an LDA speaking LMTP [RFC-LMTP] that supports the MTRK extension) SHOULD pass the tracking request to the LDA. In this case, the Action field for the MTA->LDA exchange will look the same as a transfer to a compliant MTA; that is, a "transferred" tracking Allman [Page 6] Internet Draft Message/Tracking-Status June 21, 2001 status will be issued. 4. Security Issues 4.1. Forgery Malicious servers may attempt to subvert message tracking and return false information. This could result in misdirection or misinterpretation of results. 4.2. Confidentiality Another dimension of security is confidentiality. There may be cases in which a message recipient is autoforwarding mes- sages but does not wish to divulge the address to which the mes- sages are autoforwarded. The desire for such confidentiality will probably be heightened as "wireless mailboxes", such as pagers, become more widely used as autoforward addresses. MTA authors are encouraged to provide a mechanism which enables the end user to preserve the confidentiality of a for- warding address. Depending on the degree of confidentiality required, and the nature of the environment to which a message were being forwarded, this might be accomplished by one or more of: (a) respond with a "relayed" tracking status when a message is forwarded to a confidential forwarding address, and dis- abling further message tracking requests. (b) declaring the message to be delivered, issuing a "deliv- ered" tracking status, re-sending the message to the confi- dential forwarding address, and disabling further message tracking requests. The tracking algorithms MUST NOT allow tracking through list expansions. When a message is delivered to a list, a tracking request MUST respond with an "expanded" tracking status and MUST NOT display the contents of the list. 5. References [DRAFT-MTRK-MODEL] T. Hansen, ``Message Tracking Model and Requirements.'' draft-ietf-msgtrk-model-03.txt. November 2000. [DRAFT-MTRK-MTQP] T. Hansen, ``Message Tracking Query Protocol.'' draft-ietf- msgtrk-mtqp-01.txt. November 2000. [DRAFT-MTRK-SMTPEXT] E. Allman, ``SMTP Service Extension for Message Tracking.'' draft-ietf-msgtrk-smtpext-00.txt. December 2000. Allman [Page 7] Internet Draft Message/Tracking-Status June 21, 2001 [RFC-ABNF] Crocker, D., Editor, and P. Overell, ``Augmented BNF for Syn- tax Specifications: ABNF'', RFC 2234, November 1997. [RFC-DSN-REPT] G. Vaudreuil, ``The Multipart/Report Content Type for the Reporting of Mail System Administrative Messages.'' RFC 1892. January 1996. [RFC-DSN-SMTP] K. Moore, ``SMTP Service Extension for Delivery Status Notifi- cations.'' RFC 1891. January 1996. [RFC-DSN-STAT] K. Moore and G. Vaudreuil, ``An Extensible Message Format for Delivery Status Notifications.'' RFC 1894. January 1996. [RFC-EMSSC] G. Vaudreuil, ``Enhanced Mail System Status Codes.'' RFC 1893. January 1996. [RFC-ESMTP] Rose, M., Stefferud, E., Crocker, D., Klensin, J. and N. Freed, ``SMTP Service Extensions.'' STD 10, RFC 1869. Novem- ber 1995. [RFC-HOSTREQ] R. Braden (ed.), ``Requirements for Internet Hosts -- Applica- tion and Support.'' STD 3, RFC 1123. October 1989. [RFC-KEYWORDS] S. Bradner, ``Key words for use in RFCs to Indicate Require- ment Levels.'' RFC 2119. March 1997. [RFC-LMTP] J. Myers, ``Local Mail Transfer Protocol.'' RFC 2033. Octo- ber 1996. [RFC-MDN] R. Fajman, ``An Extensible Message Format for Message Disposi- tion Notifications.'' RFC 2298. March 1998. [RFC-MIME] N. Freed and N. Borenstein, ``Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bod- ies.'' RFC 2045. November 1996. [RFC-MSGFMT] D. Crocker, ``Standard for the Format of ARPA Internet Text Messages.'' RFC 822. August 1982. [RFC-RELATED] E. Levinson, ``The MIME Multipart/Related Content-type.'' RFC 2387. August 1998. Allman [Page 8] Internet Draft Message/Tracking-Status June 21, 2001 6. Author's Address Eric Allman Sendmail, Inc. 6603 Shellmound Emeryville, CA 94608 U.S.A. E-Mail: eric@Sendmail.COM Phone: +1 510 594 5501 Fax: +1 510 594 5411 Allman [Page 9] --==_Exmh_-10955732860-- From owner-ietf-msgtrk@mail.imc.org Fri Jun 22 11:30:46 2001 Received: from above.proper.com (above.proper.com [208.184.76.39]) by ietf.org (8.9.1a/8.9.1a) with SMTP id LAA26163 for ; Fri, 22 Jun 2001 11:30:45 -0400 (EDT) Received: from localhost (localhost [[UNIX: localhost]]) by above.proper.com (8.11.3/8.11.3) id f5MFQpO10747 for ietf-msgtrk-bks; Fri, 22 Jun 2001 08:26:51 -0700 (PDT) Received: from rembrandt.esys.ca (IDENT:root@rembrandt.esys.ca [198.161.92.131]) by above.proper.com (8.11.3/8.11.3) with ESMTP id f5MFQnk10739 for ; Fri, 22 Jun 2001 08:26:49 -0700 (PDT) Received: from kepler (kepler.esys.ca [198.161.92.108]) (authenticated) by rembrandt.esys.ca (8.11.0.Beta0/8.11.0.Beta0) with ESMTP id f5MFQj329932; Fri, 22 Jun 2001 09:26:45 -0600 From: Steve Hole Date: Fri, 22 Jun 2001 09:26:05 -0600 To: Eric Allman Subject: Re: soon-to-be-submitted msgtrk drafts Cc: ietf-msgtrk@imc.org In-Reply-To: <200106220111.f5M1BYJv051179@knecht.Neophilic.COM> References: <200106220111.f5M1BYJv051179@knecht.Neophilic.COM> Message-ID: X-Mailer: Execmail for Win32 5.1.1 Build (10) MIME-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Sender: owner-ietf-msgtrk@mail.imc.org Precedence: bulk List-Archive: List-ID: List-Unsubscribe: On Thu, 21 Jun 2001 18:11:34 -0700 Eric Allman wrote: > Enclosed are the two updated drafts that I believe contain all the > comments I've received to date. I want to submit these "soon", > but I thought I would give folks here one last look-see. Very good. Please get your comments in now please because these will be going to last call as soon as they are issued. Cheers. --- Steve Hole Chief Technical Officer - Electronic Billing and Payment Systems ACI Worldwide, Messaging Direct Mailto:Steve.Hole@MessagingDirect.com Phone: 780-424-4922