Sieve Working Group K. Murchison Internet-Draft Oceana Matrix Ltd. Obsoletes: 3598 (if approved) September 12, 2005 Expires: March 16, 2006 Sieve Email Filtering -- Subaddress Extension draft-ietf-sieve-rfc3598bis-01.txt 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 March 16, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract On email systems that allow for "subaddressing" or "detailed addressing" (e.g., "ken+sieve@example.org"), it is sometimes desirable to make comparisons against these sub-parts of addresses. This document defines an extension to the Sieve mail filtering language that allows users to compare against the user and detail parts of an address. Meta-information on this document Murchison Expires March 16, 2006 [Page 1] Internet-Draft Sieve -- Subaddress Extension September 2005 This information is intended to facilitate discussion. It will be removed when this document leaves the Internet-Draft stage. This document is intended to be an update to the existing "subaddress" extension to the Sieve mail filtering language, available from the RFC repository as and respectively. This document 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 . Murchison Expires March 16, 2006 [Page 2] Internet-Draft Sieve -- Subaddress Extension September 2005 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Capability Identifier . . . . . . . . . . . . . . . . . . . . 5 3. Subaddress Comparisons . . . . . . . . . . . . . . . . . . . . 6 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 6. Normative References . . . . . . . . . . . . . . . . . . . . . 10 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 11 Appendix B. Changes since RFC3598 . . . . . . . . . . . . . . . . 12 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . . . . 14 Murchison Expires March 16, 2006 [Page 3] Internet-Draft Sieve -- Subaddress Extension September 2005 1. Introduction Subaddressing is the practice of augmenting (either by prefix or suffix) the local-part of an [RFC2822] address with some "detail" information to indicate that the message should be delivered to the mailbox specified by the "detail" information. A "separator character sequence" (typically "+"), forms the boundary between the "user" (original local-part) and "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: o A message addressed to "ken+sieve@example.org" is delivered into a mailbox called "sieve" belonging to the user "ken". o 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 [I-D.ietf-sieve-3028bis] for comparing against the "user" and "detail" sub-parts of an address. Conventions for notations are as in [I-D.ietf-sieve-3028bis] section 1.1, including use of [RFC2119]. Murchison Expires March 16, 2006 [Page 4] Internet-Draft Sieve -- Subaddress Extension September 2005 2. Capability Identifier The capability string associated with the extension defined in this document is "subaddress". Murchison Expires March 16, 2006 [Page 5] Internet-Draft Sieve -- Subaddress Extension September 2005 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. NOTE: In most cases, the envelope "to" address is the preferred 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. NOTE: Because the construction of detailed addresses can be site and/or implementation specific, using the subaddress extension on foreign addresses (such as the envelope "from" address or originator header fields) may lead to inconsistent or incorrect results. The ":user" argument specifies the user sub-part of the local-part of an address. Whether the user sub-part lies to the left or right of the separator character sequence is dependent on the encompassing mail system. If no separator character sequence exists, then ":user" specifies the entire left-side of the address (equivalent to ":localpart"). The ":detail" argument specifies the detail sub-part of the local- part of an address. Whether the detail sub-part lies to the left or right of the separator character sequence is dependent on the encompassing mail system. If no separator character sequence exists, the test evaluates to false. If the separator character sequence exists, but not detail information is provided, then ":detail" ":is" the empty key (""). Otherwise, the ":detail" sub-part ":contains" the empty key. NOTE: If the separator character sequence occurs more than once in the local-part, then the address MUST be split at the left-most separator when the detail information is a suffix and at the right-most separator when the detail information is a prefix. Implementations MUST make sure that the separator character sequence and the ordering of the user and detail sub-parts match those that are used and/or allowed by the encompassing mail system, otherwise unexpected results might occur. Implementations SHOULD allow the separator character sequence and sub-part ordering to be configurable Murchison Expires March 16, 2006 [Page 6] Internet-Draft Sieve -- Subaddress Extension September 2005 so that they may be used with a variety of mail systems. Note that the mechanisms used to define and/or query the separator character sequence and sub-part ordering used by the mail system are outside the scope of this document. The ":user" and ":detail" address parts are subject to the same rules and restrictions as the standard address parts defined in [I-D.ietf- sieve-3028bis]. For convenience, the "ADDRESS-PART" syntax element defined in [I-D.ietf-sieve-3028bis] is augmented here as follows: ADDRESS-PART =/ ":user" / ":detail" A diagram showing the ADDRESS-PARTs of a email address where the detail information follows a separator character sequence of "+" is shown below: :user "+" :detail "@" :domain `-----------------' :local-part A diagram showing the ADDRESS-PARTs of a email address where the detail information precedes a separator character sequence of "--" is shown below: :detail "--" :user "@" :domain `------------------' :local-part Murchison Expires March 16, 2006 [Page 7] Internet-Draft Sieve -- Subaddress Extension September 2005 Example (where the detail information follows "+"): 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 directly to me (ignoring +detail), junk it. if not allof (address :user ["to", "cc"] "ken", address :domain ["to", "cc"] "example.org") { discard; } # Redirect all mail sent to +foo. if envelope :detail "to" "foo" { redirect "ken@example.edu"; } Murchison Expires March 16, 2006 [Page 8] Internet-Draft Sieve -- Subaddress Extension September 2005 4. IANA Considerations This document requests that the IANA update the entry for the "subaddress" Sieve extension to point at this document. Murchison Expires March 16, 2006 [Page 9] Internet-Draft Sieve -- Subaddress Extension September 2005 5. Security Considerations Security considerations are discussed in [I-D.ietf-sieve-3028bis]. It is believed that this extension does not introduce any additional security concerns. 6. Normative References [I-D.ietf-sieve-3028bis] Showalter, T. and P. Guenther, "Sieve: An Email Filtering Language", draft-ietf-sieve-3028bis-04 (work in progress), July 2005. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2822] Resnick, P., "Internet Message Format", RFC 2822, April 2001. Murchison Expires March 16, 2006 [Page 10] Internet-Draft Sieve -- Subaddress Extension September 2005 Appendix A. Acknowledgments Thanks to Tim Showalter, Alexey Melnikov, Michael Salmon, Randall Gellens, Philip Guenther and Jutta Degener for their help with this document. Murchison Expires March 16, 2006 [Page 11] Internet-Draft Sieve -- Subaddress Extension September 2005 Appendix B. Changes since RFC3598 o Allow detail information to be either or prefix or suffix to the user. o Allow boundary between user and detail parts to be multiple characters. o Added note regarding processing of local-part with multiple separator character sequences. o Fixed envelope test example to only use "to" address. o Refer to the zero-length string ("") as "empty" instead of "null" (per draft-ietf-sieve-3028bis) o Miscellaneous editorial changes. Murchison Expires March 16, 2006 [Page 12] Internet-Draft Sieve -- Subaddress Extension September 2005 Author's Address Kenneth Murchison Oceana Matrix Ltd. 2495 Main St. Suite 401 Buffalo, NY 14214 US Phone: +1 716 604 0088 Email: ken@oceana.com Murchison Expires March 16, 2006 [Page 13] Internet-Draft Sieve -- Subaddress Extension September 2005 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2005). 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. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Murchison Expires March 16, 2006 [Page 14]