EXTRA K. Murchison Internet-Draft B. Gondwana Updates: 5230, 5435 (if approved) FastMail Intended status: Standards Track January 11, 2018 Expires: July 15, 2018 Sieve Extension: File Carbon Copy (Fcc) draft-ietf-extra-sieve-fcc-01 Abstract The Sieve Email Filtering Language provides a number of action commands, some of which can generate additional messages on behalf of the user. This document defines an extension to such commands to allow a copy of any generated message to be filed into a target mailbox. 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 https://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 July 15, 2018. Copyright Notice Copyright (c) 2018 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 (https://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 Murchison & Gondwana Expires July 15, 2018 [Page 1] Internet-Draft Sieve Fcc January 2018 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions Used in This Document . . . . . . . . . . . . . . 2 3. Tagged Argument ":fcc" . . . . . . . . . . . . . . . . . . . 3 3.1. Interaction with the Vacation Action . . . . . . . . . . 3 3.2. Interaction with the Notify Action . . . . . . . . . . . 4 3.3. Compatibility with the Reject and Extended Reject Actions . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.4. Compatibility with Other Actions . . . . . . . . . . . . 4 3.5. Interaction with Fileinto Extensions . . . . . . . . . . 4 3.5.1. Imap4flags Extension . . . . . . . . . . . . . . . . 5 3.5.2. Mailbox Extension . . . . . . . . . . . . . . . . . . 5 3.5.3. Special-Use Extension . . . . . . . . . . . . . . . . 5 3.5.4. Extended Example . . . . . . . . . . . . . . . . . . 6 4. Security Considerations . . . . . . . . . . . . . . . . . . . 6 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 5.1. Registration of Sieve Extension . . . . . . . . . . . . . 6 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 7.1. Normative References . . . . . . . . . . . . . . . . . . 6 7.2. Informative References . . . . . . . . . . . . . . . . . 7 Appendix A. Change History (To be removed by RFC Editor before publication) . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction The Sieve Email Filtering Language [RFC5228] provides a number of action commands, some of which can generate additional messages on behalf of the user. Two such commands are defined by the Vacation [RFC5230] and Notify [RFC5435] extensions. It is sometimes desirable to have an archive of the messages generated by these commands. This extension defines a new optional tagged argument ":fcc" to action commands which generate additional messages to allow a copy of the generated message to be filed into a target mailbox. The capability string associated with this extension is "fcc". 2. Conventions Used in This Document Conventions for notations are as in Section 1.1 of [RFC5228], including use of the "Usage:" label for the definition of action and tagged arguments syntax. Murchison & Gondwana Expires July 15, 2018 [Page 2] Internet-Draft Sieve Fcc January 2018 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 3. Tagged Argument ":fcc" Usage: ":fcc" FCC-OPTIONS The positional FCC-OPTIONS argument is defined here in ABNF [RFC4234] syntax so that it can be modified by other extensions. FCC-OPTIONS = "" ; empty string If the optional ":fcc" argument is specified with an action that generates an additional message, it instructs the Sieve interpreter to file a copy of the generated message into the target mailbox. If the specified mailbox doesn't exist, the implementation MAY treat it as an error, create the mailbox, or file the message into an implementation-defined mailbox. 3.1. Interaction with the Vacation Action This document extends the "vacation" [RFC5230] action (see also "vacation-seconds" [RFC6131]) to optionally store a copy of the auto- reply messages into a target mailbox. Usage: vacation [":days" number | ":seconds" number] [":subject" string] [":from" string] [":addresses" string-list] [":mime"] [":handle" string] [":fcc" FCC-OPTIONS ] Example: require ["vacation", "fcc"]; vacation :days 7 :fcc "INBOX.Sent" :from "hemingway@example.com" "Gone Fishin'"; Murchison & Gondwana Expires July 15, 2018 [Page 3] Internet-Draft Sieve Fcc January 2018 3.2. Interaction with the Notify Action This document extends the "notify" [RFC5435] action to optionally store a copy of the notification messages into a target mailbox. Usage: notify [":from" string] [":importance" <"1" / "2" / "3">] [":options" string-list] [":message" string] [":fcc" FCC-OPTIONS ] Example: require ["enotify", "fcc"]; notify :message "You got mail!" :fcc "INBOX.Sent" "mailto:ken@example.com"; 3.3. Compatibility with the Reject and Extended Reject Actions "fcc" MUST be incompatible with the "reject" and "ereject" [RFC5429] actions. Making "fcc" compatible with these actions violates the SMTP [RFC5321] principle that a message is either delivered or bounced back to the sender. Namely, the saved copy of the rejection message will contain the original message. It is an error for a script to use the ":fcc" tagged argument with either "reject" or "ereject". 3.4. Compatibility with Other Actions The "fcc" extension is not compatible with any Sieve action that does not generate an additional message on behalf of the user. It is an error for a script to use the ":fcc" tagged argument with any such action. Future extensions that define actions that generate additional messages on behalf of the user should describe their compatibility with ":fcc". 3.5. Interaction with Fileinto Extensions The "fcc" extension can be used with some tagged arguments defined in extensions to the "fileinto" action. The sections below describe its interaction with currently defined extensions. Tagged arguments in Murchison & Gondwana Expires July 15, 2018 [Page 4] Internet-Draft Sieve Fcc January 2018 future extensions to the "fileinto" command should describe their interaction with ":fcc", if any. 3.5.1. Imap4flags Extension This document extends the definition of the ":flags" [RFC5232] tagged argument so that it can be used as an FCC-OPTIONS to the ":fcc" argument. FCC-OPTIONS =/ [":flags" ] If the optional ":flags" argument is specified with ":fcc", it instructs the Sieve interpreter to set the IMAP4 flags provided in the subsequent argument when the generated message is filed into the target mailbox. 3.5.2. Mailbox Extension This document extends the definition of the ":create" [RFC5490] tagged argument so that it can be used as an FCC-OPTIONS to the ":fcc" argument. FCC-OPTIONS =/ [":create"] If the optional ":create" argument is specified with ":fcc", it instructs the Sieve interpreter to create the target mailbox, if needed, before attempting to file the generated message into the target mailbox. 3.5.3. Special-Use Extension This document extends the definition of the ":specialuse" [I-D.ietf-extra-sieve-special-use] tagged argument so that it can be used as an FCC-OPTIONS to the ":fcc" argument. FCC-OPTIONS =/ [":specialuse "] If the optional ":specialuse" argument is specified with ":fcc", it instructs the Sieve interpreter to check whether a mailbox exists with the specific special-use flag assigned to it. If such a mailbox exists, the generated message is filed into the special-use mailbox. Otherwise, the generated message is filed into the target mailbox. If both the optional ":specialuse" and ":create" arguments are specified with ":fcc", the Sieve interpreter is instructed to create the target mailbox per Section 4.1 of [I-D.ietf-extra-sieve-special-use], if needed. Murchison & Gondwana Expires July 15, 2018 [Page 5] Internet-Draft Sieve Fcc January 2018 3.5.4. Extended Example require ["vacation", "fcc", "mailbox", "special-use", "imap4flags"]; vacation :days 7 :fcc :specialuse "\\Sent" :create :flags ["\\Seen"] "INBOX.Sent" :from "hemingway@example.com" "Gone Fishin'"; 4. Security Considerations The "fcc" extension does not raise any other security considerations that are not already present in [RFC5228], [RFC5230], [RFC5435], and [RFC6131]. 5. IANA Considerations 5.1. Registration of Sieve Extension To: iana@iana.org Subject: Registration of new Sieve extension Capability name: fcc Description: Adds the ":fcc" parameter to Sieve action commands that generate additional messages. RFC number: RFC XXXX Contact address: The Sieve discussion list 6. Acknowledgments The authors would like to thank the following individuals for contributing their ideas and support for writing this specification: Ned Freed, Stan Kalisch. 7. References 7.1. Normative References [I-D.ietf-extra-sieve-special-use] Bosch, S., "Sieve Email Filtering: Delivering to Special- Use Mailboxes", draft-ietf-extra-sieve-special-use-01 (work in progress), January 2018. Murchison & Gondwana Expires July 15, 2018 [Page 6] Internet-Draft Sieve Fcc January 2018 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 4234, DOI 10.17487/RFC4234, October 2005, . [RFC5228] Guenther, P., Ed. and T. Showalter, Ed., "Sieve: An Email Filtering Language", RFC 5228, DOI 10.17487/RFC5228, January 2008, . [RFC5230] Showalter, T. and N. Freed, Ed., "Sieve Email Filtering: Vacation Extension", RFC 5230, DOI 10.17487/RFC5230, January 2008, . [RFC5232] Melnikov, A., "Sieve Email Filtering: Imap4flags Extension", RFC 5232, DOI 10.17487/RFC5232, January 2008, . [RFC5435] Melnikov, A., Ed., Leiba, B., Ed., Segmuller, W., and T. Martin, "Sieve Email Filtering: Extension for Notifications", RFC 5435, DOI 10.17487/RFC5435, January 2009, . [RFC5490] Melnikov, A., "The Sieve Mail-Filtering Language -- Extensions for Checking Mailbox Status and Accessing Mailbox Metadata", RFC 5490, DOI 10.17487/RFC5490, March 2009, . 7.2. Informative References [RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321, DOI 10.17487/RFC5321, October 2008, . [RFC5429] Stone, A., Ed., "Sieve Email Filtering: Reject and Extended Reject Extensions", RFC 5429, DOI 10.17487/RFC5429, March 2009, . [RFC6131] George, R. and B. Leiba, "Sieve Vacation Extension: "Seconds" Parameter", RFC 6131, DOI 10.17487/RFC6131, July 2011, . Murchison & Gondwana Expires July 15, 2018 [Page 7] Internet-Draft Sieve Fcc January 2018 Appendix A. Change History (To be removed by RFC Editor before publication) Changes since draft-ietf-extra-sieve-fcc-00: o Updated abstract with text from Ned. o Added support for :fcc to notify extension. o Prohibit use of :fcc with reject and ereject extensions. o Added registration of the extension with IANA. o Added Acknowledgments. o Minor editorial changes. Authors' Addresses Kenneth Murchison FastMail Pty Ltd Level 2, 114 William Street Melbourne, VIC 3000 Australia Email: murch@fastmailteam.com Bron Gondwana FastMail Pty Ltd Level 2, 114 William Street Melbourne, VIC 3000 Australia Email: brong@fastmailteam.com Murchison & Gondwana Expires July 15, 2018 [Page 8]