Sieve Support for Dovecot


Pigeonhole is the name of the project that adds support for the Sieve language (RFC 5228) and the ManageSieve protocol (RFC 5804) to the Dovecot Secure IMAP Server. In the literal sense, a pigeonhole is a a hole or recess inside a dovecot for pigeons to nest in. It is, however, also the name for one of a series of small, open compartments in a cabinet used for filing or sorting mail. As a verb, it describes the act of putting an item into one of those pigeonholes. The name `Pigeonhole' therefore well describes an important part of the functionality that this project adds to Dovecot: sorting and filing e-mail messages.

The Sieve language is used to specify how e-mail needs to be processed. By writing Sieve scripts, users can customize how messages are delivered, e.g. whether they are forwarded or stored in special folders. Unwanted messages can be discarded or rejected, and, when the user is not available, the Sieve interpreter can send an automated reply. Above all, the Sieve language is meant to be simple, extensible and system independent. And, unlike most other mail filtering script languages, it does not allow users to execute arbitrary programs. This is particularly useful to prevent virtual users from having full access to the mail store. The intention of the language is to make it impossible for users to do anything more complex (and dangerous) than write simple mail filters.

Using the ManageSieve protocol, users can upload their Sieve scripts remotely, without needing direct filesystem access through FTP or SCP. Additionally, a ManageSieve server always makes sure that uploaded scripts are valid, preventing compile failures at mail delivery.

The Pigeonhole project provides Sieve support as a plugin to Dovecot's Local Delivery Agent (LDA). The ManageSieve protocol is provided is an additional service, next to Dovecot's own POP3 and IMAP services.




Check the TODO file for an up-to-date list of open issues and current development.


The ManageSieve protocol (as specified in RFC 5804) is supported.

Check the TODO file for an up-to-date list of open issues and current development.


Pigeonhole is open source and distributed under the same license as Dovecot: LGPL v2.1

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