This document defines a new test command "duplicate" for the "Sieve"
email filtering 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 or other
parts of the message.
Review and Consensus
The document was discussed by a few participants within the Applications
Area Working Group and it has the consensus of the working group. The
document was also discussed on the Sieve mailing list, <email@example.com>.
There are at least two implementations of this extension. Reviews have
been done at various times by several active Sieve participants and
implementors. IETF last call resulted in just one minor point, from the
Document Shepherd: Ned Freed <firstname.lastname@example.org>
Responsible Area Director: Barry Leiba < email@example.com>