Sieve Working Group B. Leiba Internet-Draft IBM T.J. Watson Research Center Intended status: Standards Track M. Haardt Expires: January 9, 2008 freenet AG July 8, 2007 Sieve Notification Mechanism: mailto draft-ietf-sieve-notify-mailto-04 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute 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 Internet-Draft will expire on January 9, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Leiba & Haardt Expires January 9, 2008 [Page 1] Internet-Draft Sieve Notification Mechanism: mailto July 2007 Abstract This document describes a profile of the Sieve extension for notifications, to allow notifications to be sent by electronic mail. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2. Conventions used in this document . . . . . . . . . . . . . 3 2. Definition . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Notify parameter "method" . . . . . . . . . . . . . . . . . 4 2.2. Test notify_method_capability . . . . . . . . . . . . . . . 4 2.3. Notify tag ":from" . . . . . . . . . . . . . . . . . . . . . 4 2.4. Notify tag ":importance" . . . . . . . . . . . . . . . . . . 4 2.5. Notify tag ":options" . . . . . . . . . . . . . . . . . . . 4 2.6. Notify tag ":message" . . . . . . . . . . . . . . . . . . . 4 2.7. Other Definitions . . . . . . . . . . . . . . . . . . . . . 5 3. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4. Internationalization Considerations . . . . . . . . . . . . 9 5. Security Considerations . . . . . . . . . . . . . . . . . . 10 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . 11 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 7.1. Normative References . . . . . . . . . . . . . . . . . . . . 12 7.2. Non-Normative References . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . 14 Leiba & Haardt Expires January 9, 2008 [Page 2] Internet-Draft Sieve Notification Mechanism: mailto July 2007 1. Introduction 1.1. Overview The [Notify] extension to the [Sieve] mail filtering language is a framework for providing notifications by employing URIs to specify the notification mechanism. This document defines how [mailto] URIs are used to generate notifications by e-mail. 1.2. Conventions used in this document Conventions for notations are as in [Sieve] section 1.1, including the use of [Kwds]. 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 [Kwds]. Leiba & Haardt Expires January 9, 2008 [Page 3] Internet-Draft Sieve Notification Mechanism: mailto July 2007 2. Definition The mailto mechanism results in the sending of a new email message (a "notification message") to notify a recipient about a "triggering message". 2.1. Notify parameter "method" The mailto notification mechanism uses standard mailto URIs as specified in [mailto]. 2.2. Test notify_method_capability The notify_method_capability test for "online" may return "yes" or "no" only if the Sieve processor can determine with certainty whether or not the recipients of the notification message are online and logged in. Otherwise, the test returns "maybe" for this notification method. 2.3. Notify tag ":from" The :from tag overrides the default sender of the notification message. "Sender", here, refers to the value used in the [RFC2822] "From" header. Implementations MAY also use this value in the [RFC2821] "MAIL FROM" command (the "envelope sender"), or they may prefer to establish a mailbox that receives bounces from notification messages. 2.4. Notify tag ":importance" The :importance tag has no special meaning for this notification mechanism, and this specification puts no restriction on its use. Implementations MAY use the value of :importance to set a priority or importance indication on the notification message (perhaps a visual indication, or perhaps making use of one of the non-standard but commonly used message headers). 2.5. Notify tag ":options" This tag is not used by the mailto method. 2.6. Notify tag ":message" The value of this tag, if it is present, is used as the subject of the notification message, and overrides all other mechanisms for determining the subject (as described below). Its value SHOULD NOT normally be truncated, though it may be sensible to truncate an excessively long value. Leiba & Haardt Expires January 9, 2008 [Page 4] Internet-Draft Sieve Notification Mechanism: mailto July 2007 2.7. Other Definitions Because the receipt of an email message is generating another email message, implementations MUST take steps to avoid mail loops. The notification message contains the "Received:" fields from the triggering message to allow loop detection as described in [RFC2821], section 6.2. The implementation MUST allow messages with empty envelope senders to trigger notifications. Because this notification method uses a store-and-forward system for delivery of the notification message, the Sieve processor should not have a need to retry notifications. Therefore, implementations of this method SHOULD use normal mechanisms for submitting SMTP messages and for retrying the initial submission. Once the notification message is submitted, implementations MUST NOT resubmit it, as this is likely to result in multiple notifications, and increases the danger of message loops. The overall notification message is composed using the following guidelines (see [RFC2822] for references to message header fields): o Unless overridden by ":from", the "From:" header field and the envelope sender of the notification message are set either to the envelope "to" field from the triggering message, as used by Sieve, or to a fixed address (so it "comes from the notification system"), at the discretion of the implementation. This may not be overridden by a "from" URI header, and any such URI header will be ignored. o The "To:" header field and the envelope recipient(s) of the notification message are set to the address(es) specified in the URI (including any URI headers where the hname is "to"). o The "Subject:" field of the notification message contains the value defined by the :message notify tag, as described in [Notify]. If there is no :message tag and there is a "subject" header on the URI, then that value is used. If that is also absent, the subject is retained from the triggering message. Note that Sieve [Variables] can be used to advantage here, as shown in the example in Section 3. o If the mailto URI contains a "body" header, the value of that header is used as the body of the notification message. If there is no "body" header, it is up to the implementation whether to leave the body empty or to use an excerpt of the original message. o The "Received:" fields from the triggering message are retained in the notification message, as these may help detect and prevent Leiba & Haardt Expires January 9, 2008 [Page 5] Internet-Draft Sieve Notification Mechanism: mailto July 2007 mail loops. URI headers with hname "received" are considered unsafe, and will be ignored. o Other header fields of the notification message that are normally related to an individual new message (such as "Message-ID" and "Date") are generated for the notification message in the normal manner. Any URI headers with those names are ignored. Further, the "Date" header serves as the notification timestamp defined in [Notify]. o All other header fields of the notification message either are as specified by URI headers, or have implementation-specific values; their values are not defined here. It is suggested that the implementation capitalizes the first letter of URI headers and adds a space character after the colon between the mail header name and value when adding URI headers to the message. Leiba & Haardt Expires January 9, 2008 [Page 6] Internet-Draft Sieve Notification Mechanism: mailto July 2007 3. Examples Triggering message (received by recipient@example.org): Return-Path: Received: from mail.example.com by mail.example.org for ; Wed, 7 Dec 2005 05:08:02 -0500 Received: from hobbies.example.com by mail.example.com for ; Wed, 7 Dec 2005 02:00:26 -0800 Message-ID: <1234567.89ABCDEF@example.com> Date: Wed, 07 Dec 2005 10:59:19 +0100 Precedence: list List-Id: Knitting Mailing List Sender: knitting-bounces@example.com Errors-To: knitting-bounces@example.com From: "Jeff Smith" To: "Knitting Mailing List" Subject: [Knitting] A new sweater I just finished a great new sweater! Sieve script (run on behalf of recipient@example.org): require ["notify", "variables"]; if header :contains "list-id" "knitting.example.com" { if header :matches "Subject" "[*] *" { notify :message "From ${1} list: ${2}" :importance "3" "mailto:0123456789@sms.example.net"; } } Notification message: Received: from mail.example.com by mail.example.org for ; Wed, 7 Dec 2005 05:08:02 -0500 Received: from hobbies.example.com by mail.example.com for ; Wed, 7 Dec 2005 02:00:26 -0800 Date: Wed, 7 Dec 2005 05:08:55 -0500 Message-ID: From: To: <0123456789@sms.example.net> Subject: From Knitting list: A new sweater Leiba & Haardt Expires January 9, 2008 [Page 7] Internet-Draft Sieve Notification Mechanism: mailto July 2007 Note that: o Fields such as "Message-ID:" and "Date:" were generated afresh for the notification message, and do not relate to the triggering message. o Additional "Received:" fields will be added to the notification message in transit; the ones shown were copied from the triggering message. o If this message should appear at the mail.example.org server again, the server can use the presence of a "mail.example.org" received line to avoid sending another notification. Leiba & Haardt Expires January 9, 2008 [Page 8] Internet-Draft Sieve Notification Mechanism: mailto July 2007 4. Internationalization Considerations This specification introduces no specific internationalization issues that are not already addressed in [Sieve] and in [Notify]. Leiba & Haardt Expires January 9, 2008 [Page 9] Internet-Draft Sieve Notification Mechanism: mailto July 2007 5. Security Considerations Sending a notification is comparable with forwarding mail to the notification recipient. Care must be taken when forwarding mail automatically, to ensure that confidential information is not sent into an insecure environment. The automated sending of email messages exposes the system to mail loops, which can cause operational problems. Implementations of this specification MUST protect themselves against mail loops (see Section 2.7). Additional security considerations are discussed in [Sieve] and in [Notify]. Leiba & Haardt Expires January 9, 2008 [Page 10] Internet-Draft Sieve Notification Mechanism: mailto July 2007 6. IANA Considerations The following template specifies the IANA registration of the Sieve notification mechanism specified in this document: To: iana@iana.org Subject: Registration of new Sieve notification mechanism Mechanism name: mailto Mechanism URI: RFC2368 Mechanism-specific tags: none Standards Track/IESG-approved experimental RFC number: this RFC Person and email address to contact for further information: Michael Haardt This information should be added to the list of sieve notification mechanisms given on http://www.iana.org/assignments/sieve-notification. Leiba & Haardt Expires January 9, 2008 [Page 11] Internet-Draft Sieve Notification Mechanism: mailto July 2007 7. References 7.1. Normative References [Kwds] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [Notify] Melnikov, A., Ed., Leiba, B., Ed., Segmuller, W., and T. Martin, "Sieve Extension: Notifications", work in progress, draft-ietf-sieve-notify, December 2005. [RFC2822] Resnick, P., Ed., "Internet Message Format", RFC 2822, April 2001. [Sieve] Guenther, P., Ed. and T. Showalter, Ed., "Sieve: An Email Filtering Language", work in progress, draft-ietf-sieve-3028bis, November 2005. [mailto] Hoffman, P., Masinter, L., and J. Zawinski, "The mailto URL scheme", RFC 2368, July 1998. 7.2. Non-Normative References [RFC2821] Klensin, J., Ed., "Simple Mail Transfer Protocol", RFC 2821, April 2001. [Variables] Homme, K., "Sieve Extension: Variables", work in progress, draft-ietf-sieve-variables, October 2005. Leiba & Haardt Expires January 9, 2008 [Page 12] Internet-Draft Sieve Notification Mechanism: mailto July 2007 Authors' Addresses Barry Leiba IBM T.J. Watson Research Center 19 Skyline Drive Hawthorne, NY 10532 US Phone: +1 914 784 7941 Email: leiba@watson.ibm.com Michael Haardt freenet AG Willstaetter Str. 13 Duesseldorf, NRW 40549 Germany Phone: +49 241 53087 520 Email: michael.haardt@freenet.ag Leiba & Haardt Expires January 9, 2008 [Page 13] Internet-Draft Sieve Notification Mechanism: mailto July 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Leiba & Haardt Expires January 9, 2008 [Page 14]