Network Working Group K. Murchison Document: draft-murchison-sieve-subaddress-04.txt Oceana Matrix Ltd. Expires December 15, 2002 10 June 2002 Sieve -- Subaddress 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 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 To view the list Internet-Draft Shadow Directories, see http://www.ietf.org/shadow.html. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society 2002. All Rights Reserved. Abstract On email systems that allow for "subaddressing" or "detailed addressing" (eg, "ken+sieve@example.org"), it is sometimes desirable to make comparisons against these sub-parts of addresses. This draft defines an extension to the Sieve mail filtering language that allows users to compare against the user and detail parts of an address. Expires December 15, 2002 Murchison [Page 1] Internet Draft Sieve -- Subaddress Extension June 10, 2002 Table of Contents Status of this Memo . . . . . . . . . . . . . . . . . . . . . . . . 1 Copyright Notice . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 0. Meta-information on this draft . . . . . . . . . . . . . . . 3 0.1. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 3 0.2. Noted Changes . . . . . . . . . . . . . . . . . . . . . . . . 3 0.2.1 since -03 . . . . . . . . . . . . . . . . . . . . . . . . . . 3 0.2.2 since -02 . . . . . . . . . . . . . . . . . . . . . . . . . . 3 0.2.3 since -01 . . . . . . . . . . . . . . . . . . . . . . . . . . 3 0.2.4 since -00 . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Capability Identifier . . . . . . . . . . . . . . . . . . . . 4 3. Subaddress Comparisons . . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . 6 5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 6. Author's Address . . . . . . . . . . . . . . . . . . . . . . 6 Appendix A. References . . . . . . . . . . . . . . . . . . . . . . 7 Appendix B. Full Copyright Statement . . . . . . . . . . . . . . . 7 Expires December 15, 2002 Murchison [Page 2] Internet Draft Sieve -- Subaddress Extension June 10, 2002 0. Meta-information on this draft This information is intended to facilitate discussion. It will be removed when this document leaves the Internet-Draft stage. 0.1. Discussion This draft is intended to be an extension to the Sieve mail filtering language, available from the RFC repository as . This draft and the Sieve language itself are being discussed on the MTA Filters mailing list at . Subscription requests can be sent to (send an email message with the word "subscribe" in the body). More information on the mailing list along with a WWW archive of back messages is available at . 0.2. Noted Changes 0.2.1 since -03 Editorial changes (re-submission). 0.2.2 since -02 Decided on :user and :detail as sub-parts (removed Known Issues). Noted that separator character MUST match the one used by the mail system. Editorial changes. 0.2.3 since -01 Added description of subaddressing inspired by Randy Gellens. Added discussion of handling different separator characters. Editorial changes. Expires December 15, 2002 Murchison [Page 3] Internet Draft Sieve -- Subaddress Extension June 10, 2002 0.2.4 since -00 Added augmented ADDRESS-PART syntax element. Editorial changes. 1. Introduction Subaddressing is the practice of appending some "detail" information to the local-part of an [IMAIL] address to indicate that the message should be delivered to the set of messages specified by the "detail" information. The "detail" information is prefixed with a special "separator character" (typically "+") which forms the boundary between the "user" (original local-part) and the "detail" sub-parts of the address, much like the "@" character forms the boundary between the local-part and domain. Typical uses of subaddressing might be: - A message addressed to "ken+sieve@example.org" is delivered into a mailbox called "sieve" belonging to the user "ken". - A message addressed to "5551212#123@example.org" is delivered to the voice mailbox number "123" at phone number "5551212". This document describes an extension to the Sieve language defined by [SIEVE] for comparing against the "user" and "detail" sub-parts of an address. Conventions for notations are as in [SIEVE] section 1.1, including use of [KEYWORDS]. 2. Capability Identifier The capability string associated with the extension defined in this document is "subaddress". 3. Subaddress Comparisons Commands that act exclusively on addresses may take the optional tagged arguments ":user" and ":detail" to specify what sub-part of the local-part of the address will be acted upon. Expires December 15, 2002 Murchison [Page 4] Internet Draft Sieve -- Subaddress Extension June 10, 2002 NOTE: In most cases, the envelope "to" address is the prefered address to examine for subaddress information when the desire is to sort messages based on how they were addressed so as to get to a specific recipient. The envelope address is, after all, the reason a given message is being processed by a given sieve script for a given user. This is particularly true when mailing lists, aliases, and "virtual domains" are involved since the envelope may be the only source of detail information for the specific recipient. The ":user" argument specifies that sub-part of the local-part which lies to the left of the separator character (eg, "ken" in "ken+sieve@example.org"). If no separator character exists, then ":user" specifies the entire left-side of the address (equivalent to ":localpart"). The ":detail" argument specifies that sub-part of the local-part which lies to the right of the separator character (eg, "sieve" in "ken+sieve@example.org"). If no separator characater exists, or nothing lies to the right of the separator character, then ":detail" ":is" the null key (""). Implementations MUST make sure that the separator character matches that which is used and/or allowed by the encompassing mail system, otherwise unexpected results might occur. Implementations SHOULD allow the separator character to be configurable so that they may be used with a variety of mail systems. The ":user" and ":detail" address parts are subject to the same rules and restrictions as the standard address parts defined in [SIEVE]. For convenience, the "ADDRESS-PART" syntax element defined in [SIEVE] is augmented here as follows: ADDRESS-PART =/ ":user" / ":detail" A diagram showing the ADDRESS-PARTs of a email address utilizing a separator character of '+' is shown below: :user "+" :detail "@" :domain `-----------------' :local-part Expires December 15, 2002 Murchison [Page 5] Internet Draft Sieve -- Subaddress Extension June 10, 2002 Example: require "subaddress"; # File mailing list messages (subscribed as "ken+mta-filters"). if envelope :detail "to" "mta-filters" { fileinto "inbox.ietf-mta-filters"; } # If a message is not to me (ignoring +detail), junk it. if not allof (address :user ["to", "cc", "bcc"] "ken", address :domain ["to", "cc", "bcc"] "example.org") { discard; } # Redirect all mail sent to +foo. if address :detail ["to", "cc", "bcc"] "foo" { redirect "ken@example.edu"; } 4. Security Considerations Security considerations are discussed in [SIEVE]. It is believed that this extension doesn't introduce any additional security concerns. 5. Acknowledgments Thanks to Tim Showalter, Alexey Melnikov, Michael Salmon, Randall Gellens and Philip Guenther for their help with this document. 6. Author's Address Kenneth Murchison Oceana Matrix Ltd. 21 Princeton Place Orchard Park, NY 14127 Phone: (716) 662-8973 EMail: ken@oceana.com Expires December 15, 2002 Murchison [Page 6] Internet Draft Sieve -- Subaddress Extension June 10, 2002 Appendix A. References [IMAIL] Resnick, P., Ed., "Internet Message Format", QUALCOMM Incorporated, RFC 2822, April 2001. [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", Harvard University, RFC 2119, March 1997. [SIEVE] Showalter, T., "Sieve: A Mail Filtering Language", Mira¡ point, Inc., RFC 3028, January 2001. Appendix B. Full Copyright Statement Copyright (C) The Internet Society 2002. All Rights Reserved. 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