Individual submission D. Crocker Internet-Draft Brandenburg InternetWorking Intended status: Standards Track M. Kucherawy Expires: June 4, 2012 Cloudmark, Inc. December 2, 2011 Indicating Email Handling States in Trace Fields draft-kucherawy-received-state-01 Abstract This memo registers a trace field clause for use in indicating transitions between handling queues, including enacting inter-host message transitions. This might include message quarantining, mailing list moderation, timed delivery, or other similar causes. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on June 4, 2012. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Crocker & Kucherawy Expires June 4, 2012 [Page 1] Internet-Draft Email Handling States December 2011 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Keywords . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. New Trace Clause . . . . . . . . . . . . . . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 4.1. Mail Parameters Additional-registered-clauses Sub-Registry . . . . . . . . . . . . . . . . . . . . . . . 4 4.2. Mail Parameters Registered-states Sub-Registry . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 6. Normative References . . . . . . . . . . . . . . . . . . . . . 6 Appendix A. Trace Field Examples . . . . . . . . . . . . . . . . . 6 A.1. Typical Delivery Without Obvious Delays . . . . . . . . . . 6 A.2. Delivery With Moderation . . . . . . . . . . . . . . . . . 7 Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . . 7 Crocker & Kucherawy Expires June 4, 2012 [Page 2] Internet-Draft Email Handling States December 2011 1. Introduction [SMTP] defines the content of email message trace fields, commonly the "Received" field. These are typically used to record an audit trail of the path a message follows from origin to destination. There are some cases where there may be large time gaps between trace fields. Though this might be caused by transient delivery issues, they might also be caused by policy decisions or special processing regarding the content of the message or authorization of some identity on the message. Common examples include message quarantines (filters that delay relaying or delivery of a message pending manual operator action), or mailing list moderation rules (mailing list owner action required regarding mail from authors not subscribed to those lists). This memo registers a new optional clause that can be used in trace fields to indicate that a message entered such a special processing queue for some period. This allows analysis to reveal that the cause for a time gap in trace fields was an imposed delay rather than one caused by transient technical difficulties. 2. Keywords 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 [KEYWORDS]. 3. New Trace Clause This memo creates a new trace field clause, called "state", which can be used to indicate the nature of a delay imposed on relaying of a message toward its recipient(s). It is followed by a single keyword that provides that detail. An MTA or other handling agent that determines a message is about to enter a state other than normal queueing of messages for delivery SHOULD generate a trace field including one of these clauses. That is, the presence of this clause on a trace field is an indication of the entry of the message into that state; a later trace field added would indicate its departure from that state. The following keywords are defined in this document; extensions may define other registered keywords (see Section 4.2): moderation: The message entered a hold pending mailing list moderator action. Crocker & Kucherawy Expires June 4, 2012 [Page 3] Internet-Draft Email Handling States December 2011 other: The message entered a hold for reasons not covered by other keywords in this list, and not for transient technology issues. timed: The message entered a hold in order to meet a requested delivery window. quarantine: The message entered a hold pending operator action for local policy reasons. The ABNF for this clause: State = "state" queue-state-keyword queue-state-keyword = ( reg-state-keyword / unreg-state-keyword ) reg-state-keyword = ( "moderation" / "other" / "quarantine" / "timed" / additional-state-keyword ) additional-state-keyword = unstructured ; see "IANA Considerations" below unreg-state-keyword = unstructured ; from [MAIL] A transfer agent making use of this extension MAY also include header field comments to provide additional information. Use of this clause by transfer agents is OPTIONAL. 4. IANA Considerations 4.1. Mail Parameters Additional-registered-clauses Sub-Registry This memo adds to the "Additional-registered-clauses" sub-registry of the "Mail Parameters" registry, created by [SMTP], the following entry: Clause name: state Description: Indicates special queue state entry State Summary: state Reference: [this memo] Crocker & Kucherawy Expires June 4, 2012 [Page 4] Internet-Draft Email Handling States December 2011 4.2. Mail Parameters Registered-states Sub-Registry The "Mail Parameters" registry at IANA is updated by the creation of the "Registered-states" sub-registry to contain valid state keywords for use with this specification. Updates to this registry are governed by the Specification Required rules of [IANA]. Registrations must include the following entries: Name: The name of the state keyword being defined or updated Description: A brief description of the keyword's meaning Specification: The specification document that defines the queue state being registered Use: One of "current" (the state keyword is in current use), "deprecated" (the state keyword is in use but not recommended for new implementations), or "historic" (the state keyword is no longer in substantial current use). The initial registration set is as follows: +------------+---------------------------+---------------+---------+ | Name | Description | Specification | Use | +------------+---------------------------+---------------+---------+ | moderation | Held for list moderation | [this memo] | current | +------------+---------------------------+---------------+---------+ | other | Held for causes not | [this memo] | current | | | covered by other | | | | | registered state keywords | | | +------------+---------------------------+---------------+---------+ | quarantine | Held for operator action | [this memo] | current | | | due to content analysis | | | | | or local policy | | | +------------+---------------------------+---------------+---------+ | timed | Held to accommodate a | [this memo] | current | | | specific requested | | | | | delivery window | | | +------------+---------------------------+---------------+---------+ 5. Security Considerations The use of this trace information can reveal hints as to local policy that was in effect at the time of message handling. Crocker & Kucherawy Expires June 4, 2012 [Page 5] Internet-Draft Email Handling States December 2011 6. Normative References [IANA] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [SMTP] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321, October 2008. Appendix A. Trace Field Examples This section includes a sample of the new trace field clause in use. A.1. Typical Delivery Without Obvious Delays Typical message delivery Received: from newyork.example.com (newyork.example.com [192.0.2.250]) by mail-router.example.net (8.11.6/8.11.6) with ESMTP id i7PK0sH7021929 for ; Fri, Feb 15 2002 17:19:22 -0800 Received: from internal.example.com (internal.example.com [192.168.0.1]) by newyork.example.com (8.11.6/8.11.6) with ESMTP id i9MKZCRd064134 for ; Fri, Feb 15 2002 17:19:08 -0800 Example 1: Typical message delivery with no appreciable handling delays; only Received fields shown Crocker & Kucherawy Expires June 4, 2012 [Page 6] Internet-Draft Email Handling States December 2011 A.2. Delivery With Moderation Message delivery after moderation Received: from newyork.example.com (newyork.example.com [192.0.2.250]) by mail-router.example.net (8.11.6/8.11.6) with ESMTP id i7PK0sH7021929 for ; Fri, Feb 15 2002 18:33:29 -0800 Received: from internal.example.com (internal.example.com [192.168.0.1]) by newyork.example.com (8.11.6/8.11.6) with ESMTP id i9MKZCRd064134 for