Movatterモバイル変換

Network Working Group                                       K. MurchisonRequest for Comments: 3598                            Oceana Matrix Ltd.Category: Standards Track                                 September 2003Sieve Email Filtering -- Subaddress ExtensionStatus of this Memo   This document specifies an Internet standards track protocol for the   Internet community, and requests discussion and suggestions for   improvements.  Please refer to the current edition of the "Internet   Official Protocol Standards" (STD 1) for the standardization state   and status of this protocol.  Distribution of this memo is unlimited.Copyright Notice   Copyright (C) The Internet Society (2003).  All Rights Reserved.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.Table of Contents1.  Introduction. . . . . . . . . . . . . . . . . . . . . . . . .22.  Capability Identifier . . . . . . . . . . . . . . . . . . . .23.  Subaddress Comparisons. . . . . . . . . . . . . . . . . . . .24.  Security Considerations . . . . . . . . . . . . . . . . . . .45.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .46.  Normative References. . . . . . . . . . . . . . . . . . . . .47.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .58.  Intellectual Property Statement . . . . . . . . . . . . . . .59.  Author's Address. . . . . . . . . . . . . . . . . . . . . . .510. Full Copyright Statement. . . . . . . . . . . . . . . . . . .6Murchison                   Standards Track                     [Page 1]

RFC 3598                 Sieve Email Filtering            September 20031.  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 mailbox 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.   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.Murchison                   Standards Track                     [Page 2]

RFC 3598                 Sieve Email Filtering            September 2003   The ":user" argument specifies that sub-part of the local-part which   lies to the left of the separator character (e.g., "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 (e.g., "sieve" in   "ken+sieve@example.org").  If no separator character exists, the test   evaluates to false.  If nothing lies to the right of the separator   character, then ":detail" ":is" the null key ("").  Otherwise, the   ":detail" sub-part contains 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.  Note that the mechanisms used   to define and/or query the separator character 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 [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   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;Murchison                   Standards Track                     [Page 3]

RFC 3598                 Sieve Email Filtering            September 2003   }   # Redirect all mail sent to +foo.   if envelope :detail ["to", "cc", "bcc"] "foo" {     redirect "ken@example.edu";   }4.  Security Considerations   Security considerations are discussed in [SIEVE].  It is believed   that this extension does not introduce any additional security   concerns.5.  IANA Considerations   The following template specifies the IANA registration of the Sieve   extension specified in this document:   To: iana@iana.org   Subject: Registration of new Sieve extension   Capability name: subaddress   Capability keyword: subaddress   Capability arguments: N/A   Standards Track/RFC 3598   Person and email address to contact for further information:   Kenneth Murchison   ken@oceana.com   This information has been added to the list of sieve extensions given   onhttp://www.iana.org/assignments/sieve-extensions.6.  Normative References   [IMAIL]    Resnick, P., Ed., "Internet Message Format",RFC 2822,              April 2001.   [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate              Requirement Levels",BCP 14,RFC 2119, March 1997.   [SIEVE]    Showalter, T., "Sieve: A Mail Filtering Language",RFC3028, January 2001.Murchison                   Standards Track                     [Page 4]

RFC 3598                 Sieve Email Filtering            September 20037.  Acknowledgments   Thanks to Tim Showalter, Alexey Melnikov, Michael Salmon, Randall   Gellens, Philip Guenther and Jutta Degener for their help with this   document.8.  Intellectual Property Statement   The IETF takes no position regarding the validity or scope of any   intellectual property 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; neither does it represent that it   has made any effort to identify any such rights.  Information on the   IETF's procedures with respect to rights in standards-track and   standards-related documentation can be found inBCP-11.  Copies of   claims of rights made available for publication 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 implementors or users of this specification can   be obtained from the IETF Secretariat.   The IETF invites any interested party to bring to its attention any   copyrights, patents or patent applications, or other proprietary   rights which may cover technology that may be required to practice   this standard.  Please address the information to the IETF Executive   Director.9.  Author's Address   Kenneth Murchison   Oceana Matrix Ltd.   21 Princeton Place   Orchard Park, NY 14127   EMail: ken@oceana.comMurchison                   Standards Track                     [Page 5]

RFC 3598                 Sieve Email Filtering            September 200310.  Full Copyright Statement   Copyright (C) The Internet Society (2003).  All Rights Reserved.   This document and translations of it may be copied and furnished to   others, and derivative works that comment on or otherwise explain it   or assist in its implementation may be prepared, copied, published   and distributed, in whole or in part, without restriction of any   kind, provided that the above copyright notice and this paragraph are   included on all such copies and derivative works.  However, this   document itself may not be modified in any way, such as by removing   the copyright notice or references to the Internet Society or other   Internet organizations, except as needed for the purpose of   developing Internet standards in which case the procedures for   copyrights defined in the Internet Standards process must be   followed, or as required to translate it into languages other than   English.   The limited permissions granted above are perpetual and will not be   revoked by the Internet Society or its successors or assignees.   This document and the information contained herein is provided on an   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING   TASK FORCE DISCLAIMS 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.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Murchison                   Standards Track                     [Page 6]