• Pigeonhole
• Sieve

Pigeonhole Sieve Interpreter

The Pigeonhole project provides Sieve support as a plugin for Dovecot's Local Delivery Agent (LDA) and also for its LMTP service. The plugin implements a Sieve interpreter, which filters incoming messages using a script specified in the Sieve language (RFC 5228). The Sieve script is provided by the user and, using that Sieve script, the user can customize how incoming messages are handled. Messages can be delivered to specific folders, forwarded, rejected, discarded, etc.

Configuration and Use

• Download and Installation

• Sieve Interpreter Configuration

• Sieve Usage Information

• Sieve Script Examples

• Sieve Interpreter Plugins

• Sieve Troubleshooting

Supported Features

Sieve language has various extensions. You can find more information about the extensions from the Sieve Mail Filtering Language Charter or the Sieve.info wiki page.

Note that Sieve doesn't support running external programs.

The Pigeonhole Sieve interpreter recognizes the following Sieve extensions:

• Extension	Support Status	Default Enabled	Purpose
  body	supported	yes	Allows evaluating the body of a message
  copy	supported	yes	Allows storing and forwarding messages without canceling the implicit keep
  date	supported (v0.1.12+)	yes	Adds the ability to test date and time values in various ways
  duplicate	supported (v0.4.3+)	yes	Allows detecting duplicate message deliveries
  editheader	supported (v0.3.0+)	no	Adds the ability to add and remove message header fields
  encoded-character	supported	yes	Allows encoding special characters numerically
  enotify	supported (v0.1.3+)	yes	Provides the ability to send notifications by various means (currently only mailto)
  envelope	supported	yes	Allows evaluating envelope parts, i.e. sender and recipient
  environment	supported (v0.4.0+)	yes	Allows testing against various labeled values from the execution environment
  fileinto	supported	yes	Allows storing messages in folders other than INBOX
  foreverypart	supported (v0.4.14+)	yes	Allows iterating through the message's MIME parts
  ihave	supported (v0.2.4+)	yes	Adds the ability to test for support of Sieve extensions and dynamically invoke their use
  imap4flags	supported	yes	Allows adding IMAP flags to stored messages
  imapsieve	supported (v0.4.14+)	no (plugin)	Provides access to special environment items when executing at IMAP events
  include	supported (v0.4.0+)	yes	Allows including other Sieve scripts
  index	supported (v0.4.7+)	yes	Allows matching specific header field instances by index
  mailbox	supported (v0.1.10+)	yes	Provides a mailbox existence check and allows creating mailboxes upon fileinto
  mboxmetadata	supported (v0.4.7+)	no	Provides access to mailbox METADATA entries
  mime	supported (v0.4.14+)	yes	Allows testing parts of structured MIME header fields
  extracttext	supported (v0.4.14+)	yes	Allows extracting text from individual message MIME parts
  regex	supported	yes	Provides regular expression match support
  reject	supported	yes	Allows rejecting messages with a rejection bounce message
  relational	supported	yes	Provides relational match support
  servermetadata	supported (v0.4.7+)	no	Provides access to server METADATA entries
  spamtest	supported (v0.1.16+)	no	Implements a uniform way to test against headers added by spam filters
  subaddress	supported	yes	Allows testing against delimited elements of the local part of addresses
  vacation	supported	yes	Provides auto-responder functionality, e.g. for when the user is on vacation
  vacation-seconds	supported (0.2.3+)	no	Extends vacation extension with the ability to send vacation responses with intervals of seconds rather than days
  variables	supported	yes	Adds variables support to the language
  virustest	supported (v0.1.16+)	no	Implements a uniform way to test against headers added by virus scanners
  imapflags(obsolete draft)	deprecated	no	Old version of imap4flags (for backwards compatibility with CMU Sieve)
  notify (obsolete draft)	deprecated	no	Old version of enotify (for backwards compatibility with CMU Sieve)

The following Dovecot-specific Sieve extensions are available for the Pigeonhole Sieve interpreter:

• Extension	Support Status	Default Enabled	Purpose
  vnd.dovecot.debug	supported (v0.3.0+)	no	Allows logging debug messages
  vnd.dovecot.environment	supported (v0.4.14+)	no	Extends the standard "environment" extension with extra items and a variables namespace for direct access
  vnd.dovecot.execute	plugin (v0.3+)	no	Implements executing a pre-defined set of external programs with the option to process string data through the external program
  vnd.dovecot.extdata	plugin	no	Allows a Sieve script to lookup information from a datasource external to the script
  vnd.dovecot.filter	plugin (v0.3+)	no	Implements filtering messages through a pre-defined set of external programs
  vnd.dovecot.pipe	plugin (v0.2), plugin (v0.3+)	no	Implements piping messages to a pre-defined set of external programs
  vnd.dovecot.report	supported (v0.4.14+)	no	Implements sending Messaging Abuse Reporting Format (MARF) reports (RFC 5965)

Please note that not all extensions are enabled by default, as shown in the table above. Deprecated extensions, extensions that add the ability to change messages, extensions that require explicit configuration and extensions that are still under development are not enabled without explicit configuration. This means that the sieve_extensions or sieve_global_extensions settings need to be adjusted accordingly. Also, for plugins it is not enough to add the plugin name to the sieve_plugins setting; the extensions introduced by the plugin also need to be enabled explicitly.

ManageSieve server

To give users the ability to upload their own Sieve scripts to your server, i.e. without the need for shell or FTP access, you can use the ManageSieve protocol. This is also provided by the Pigeonhole project. It is available as a separate Dovecot service. Its configuration and use is explained on the Pigeonhole ManageSieve page.