Sieve: An Email Filtering Language
RFC 5228
| Document | Type |
RFC - Proposed Standard
(January 2008; No errata)
Obsoletes RFC 3028
|
|
|---|---|---|---|
| Last updated | 2015-10-14 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Reviews | |||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 5228 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Lisa Dusseault | ||
| Send notices to | (None) | ||
Network Working Group P. Guenther, Ed.
Request for Comments: 5228 Sendmail, Inc.
Obsoletes: 3028 T. Showalter, Ed.
Category: Standards Track January 2008
Sieve: An Email Filtering Language
Status 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.
Abstract
This document describes a language for filtering email messages at
time of final delivery. It is designed to be implementable on either
a mail client or mail server. It is meant to be extensible, simple,
and independent of access protocol, mail architecture, and operating
system. It is suitable for running on a mail server where users may
not be allowed to execute arbitrary programs, such as on black box
Internet Message Access Protocol (IMAP) servers, as the base language
has no variables, loops, or ability to shell out to external
programs.
Guenther & Showalter Standards Track [Page 1]
RFC 5228 Sieve: An Email Filtering Language January 2008
Table of Contents
1. Introduction ....................................................4
1.1. Conventions Used in This Document ..........................4
1.2. Example Mail Messages ......................................5
2. Design ..........................................................6
2.1. Form of the Language .......................................6
2.2. Whitespace .................................................7
2.3. Comments ...................................................7
2.4. Literal Data ...............................................7
2.4.1. Numbers .............................................7
2.4.2. Strings .............................................8
2.4.2.1. String Lists ...............................9
2.4.2.2. Headers ....................................9
2.4.2.3. Addresses .................................10
2.4.2.4. Encoding Characters Using
"encoded-character" .......................10
2.5. Tests .....................................................11
2.5.1. Test Lists .........................................12
2.6. Arguments .................................................12
2.6.1. Positional Arguments ...............................12
2.6.2. Tagged Arguments ...................................12
2.6.3. Optional Arguments .................................13
2.6.4. Types of Arguments .................................13
2.7. String Comparison .........................................13
2.7.1. Match Type .........................................14
2.7.2. Comparisons across Character Sets ..................15
2.7.3. Comparators ........................................15
2.7.4. Comparisons against Addresses ......................16
2.8. Blocks ....................................................17
2.9. Commands ..................................................17
2.10. Evaluation ...............................................18
2.10.1. Action Interaction ................................18
2.10.2. Implicit Keep .....................................18
2.10.3. Message Uniqueness in a Mailbox ...................19
2.10.4. Limits on Numbers of Actions ......................19
2.10.5. Extensions and Optional Features ..................19
2.10.6. Errors ............................................20
2.10.7. Limits on Execution ...............................20
3. Control Commands ...............................................21
3.1. Control if ................................................21
3.2. Control require ...........................................22
3.3. Control stop ..............................................22
4. Action Commands ................................................23
4.1. Action fileinto ...........................................23
4.2. Action redirect ...........................................23
4.3. Action keep ...............................................24
4.4. Action discard ............................................25
Guenther & Showalter Standards Track [Page 2]
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