Sieve: Duplicate Extension

The duplicate extension (RFC 7352) adds a new test command called duplicate to the Sieve language. This test adds the ability to detect duplications.

The main application for this new test is handling duplicate deliveries commonly caused by mailing list subscriptions or redirected mail addresses.

The detection is normally performed by matching the message ID to an internal list of message IDs from previously delivered messages. For more complex applications, the duplicate test can also use the content of a specific header field or other parts of the message.

Changed: 3.0.0

vnd.dovecot.duplicate extension has been removed in favor of this.

Configuration

The duplicate extension is available by default.

Settings

sieve_duplicate_default_period

Default	14d
Value	time
See Also	Sieve duplicate extension
Advanced Setting; this should not normally be changed.

Default period after which tracked values are purged from the duplicate tracking database.

sieve_duplicate_max_period

Default	7d
Value	time
See Also	Sieve duplicate extension
Advanced Setting; this should not normally be changed.

Maximum period after which tracked values are purged from the duplicate tracking database.

Example

plugin {
  sieve = ~/.dovecot.sieve

  sieve_duplicate_default_period = 1h
  sieve_duplicate_max_period = 1d
}