Sieve Extension: Externally Stored Lists
RFC 6134
Internet Engineering Task Force (IETF) A. Melnikov
Request for Comments: 6134 Isode Limited
Category: Standards Track B. Leiba
ISSN: 2070-1721 Huawei Technologies
July 2011
Sieve Extension: Externally Stored Lists
Abstract
The Sieve email filtering language can be used to implement email
whitelisting, blacklisting, personal distribution lists, and other
sorts of list matching. Currently, this requires that all members of
such lists be hard-coded in the script itself. Whenever a member of
a list is added or deleted, the script needs to be updated and
possibly uploaded to a mail server.
This document defines a Sieve extension for accessing externally
stored lists -- lists whose members are stored externally to the
script, such as using the Lightweight Directory Access Protocol
(LDAP), the Application Configuration Access Protocol (ACAP), vCard
Extensions to WebDAV (CardDAV), or relational databases.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6134.
Copyright Notice
Copyright (c) 2011 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
(http://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
Melnikov & Leiba Standards Track [Page 1]
RFC 6134 Sieve Extension: Externally Stored Lists July 2011
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Conventions Used in This Document . . . . . . . . . . . . 3
2. Extlists Extension . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Capability Identifier . . . . . . . . . . . . . . . . . . 3
2.2. :list Match Type for Supported Tests . . . . . . . . . . . 3
2.3. :list Tagged Argument to the "redirect" Action . . . . . . 5
2.4. Other Uses for External Lists . . . . . . . . . . . . . . 5
2.5. Syntax of an Externally Stored List Name . . . . . . . . . 5
2.6. Definition of "addrbook" URN Parameter . . . . . . . . . . 7
2.7. Test valid_ext_list . . . . . . . . . . . . . . . . . . . 9
2.8. Interaction with ManageSieve . . . . . . . . . . . . . . . 9
2.9. Examples . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.9.1. Example 1 . . . . . . . . . . . . . . . . . . . . . . 10
2.9.2. Example 2 . . . . . . . . . . . . . . . . . . . . . . 10
2.9.3. Example 3 . . . . . . . . . . . . . . . . . . . . . . 11
2.9.4. Example 4 . . . . . . . . . . . . . . . . . . . . . . 11
2.9.5. Example 5 . . . . . . . . . . . . . . . . . . . . . . 11
3. Security Considerations . . . . . . . . . . . . . . . . . . . 12
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
4.1. Registration of Sieve Extension . . . . . . . . . . . . . 14
4.2. Registration of ManageSieve Capability . . . . . . . . . . 14
4.3. Creation of Sieve URN Parameters Registry . . . . . . . . 15
4.4. Registration of the "addrbook" URN parameter . . . . . . . 16
4.5. Registration of "sieve" URN sub-namespace . . . . . . . . 16
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.1. Normative References . . . . . . . . . . . . . . . . . . . 16
6.2. Informative References . . . . . . . . . . . . . . . . . . 17
Melnikov & Leiba Standards Track [Page 2]
RFC 6134 Sieve Extension: Externally Stored Lists July 2011
1. Introduction
This document specifies an extension to the Sieve language [RFC5228]
for checking membership in an external list or for redirecting
messages to an external list of recipients. An "external list" is a
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