EXTRA K. Murchison
Internet-Draft B. Gondwana
Updates: 5230, 5429 (if approved) FastMail
Intended status: Standards Track September 21, 2017
Expires: March 25, 2018
Sieve Extension: File Carbon Copy (Fcc)
draft-ietf-extra-sieve-fcc-00
Abstract
The Sieve Email Filtering Language consists of action commands that
can reply to the sender of an incoming message with a generated
message. This document defines an extension to such commands to
allow a copy of the generated reply message to be filed into a target
mailbox.
Open Issues
o Should :fcc be allowed with reject/ereject?
o Should there be a separate capability string for each action that
uses :fcc (e.g. "vacation-fcc")?
Status of This Memo
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Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 2
3. The ":fcc" Argument . . . . . . . . . . . . . . . . . . . . . 3
3.1. Interaction with Fileinto Extensions . . . . . . . . . . 3
3.1.1. Imap4flags Extension . . . . . . . . . . . . . . . . 3
3.1.2. Mailbox Extension . . . . . . . . . . . . . . . . . . 4
3.1.3. Special-Use Extension . . . . . . . . . . . . . . . . 4
3.1.4. Extended Example . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
The Sieve Email Filtering Language [RFC5228] consists of action
commands that can reply to the sender of an incoming message with a
generated message. Three such commands are defined by the Vacation
Extension [RFC5230] and the Reject and Extended Reject Extensions
[RFC5429]. It is sometimes desirable to have an archive of these
auto-generated reply messages.
This extension defines a ":fcc" argument to action commands which
generate reply messages to allow a copy of the reply 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. The ":fcc" Argument
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 a reply message, it instructs the Sieve interpreter to file
a copy of the 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.
Example:
require ["reject", "fcc"];
if header :contains "Subject" "Make Money Fast" {
reject :fcc "Junk" "Your message is considered junk email.";
}
3.1. 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
future extensions to the "fileinto" command should describe their use
with ":fcc", if any.
3.1.1. 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
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the subsequent argument when the the reply message is filed into the
target mailbox.
3.1.2. 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 reply message into the target
mailbox.
3.1.3. 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 reply message is filed into the special-use mailbox.
Otherwise, the reply 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.
3.1.4. 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], [RFC5429], [RFC5230], and
[RFC6131].
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5. IANA Considerations
6. References
6.1. Normative References
[]
Bosch, S., "Sieve Email Filtering: Delivering to Special-
Use Mailboxes", draft-ietf-extra-sieve-special-use-00
(work in progress), September 2017.
[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>.
[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>.
[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>.
6.2. Informative References
[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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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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