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
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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.
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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 <mailbox: string>
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 <mailbox: string>]
<reason: string>
Example:
require ["vacation", "fcc"];
vacation :days 7
:fcc "INBOX.Sent"
:from "hemingway@example.com" "Gone Fishin'";
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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 <mailbox: string>]
<method: string>
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
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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" <list-of-flags: string-list>]
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 <special-use-flag: string>"]
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.
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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 <sieve@ietf.org>
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
[]
Bosch, S., "Sieve Email Filtering: Delivering to Special-
Use Mailboxes", draft-ietf-extra-sieve-special-use-01
(work in progress), January 2018.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 4234, DOI 10.17487/RFC4234,
October 2005, <https://www.rfc-editor.org/info/rfc4234>.
[RFC5228] Guenther, P., Ed. and T. Showalter, Ed., "Sieve: An Email
Filtering Language", RFC 5228, DOI 10.17487/RFC5228,
January 2008, <https://www.rfc-editor.org/info/rfc5228>.
[RFC5230] Showalter, T. and N. Freed, Ed., "Sieve Email Filtering:
Vacation Extension", RFC 5230, DOI 10.17487/RFC5230,
January 2008, <https://www.rfc-editor.org/info/rfc5230>.
[RFC5232] Melnikov, A., "Sieve Email Filtering: Imap4flags
Extension", RFC 5232, DOI 10.17487/RFC5232, January 2008,
<https://www.rfc-editor.org/info/rfc5232>.
[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, <https://www.rfc-editor.org/info/rfc5435>.
[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, <https://www.rfc-editor.org/info/rfc5490>.
7.2. Informative References
[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
DOI 10.17487/RFC5321, October 2008,
<https://www.rfc-editor.org/info/rfc5321>.
[RFC5429] Stone, A., Ed., "Sieve Email Filtering: Reject and
Extended Reject Extensions", RFC 5429,
DOI 10.17487/RFC5429, March 2009,
<https://www.rfc-editor.org/info/rfc5429>.
[RFC6131] George, R. and B. Leiba, "Sieve Vacation Extension:
"Seconds" Parameter", RFC 6131, DOI 10.17487/RFC6131, July
2011, <https://www.rfc-editor.org/info/rfc6131>.
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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
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