Simple Mail Transfer Protocol extension for relaying Metadata

Document Type Expired Internet-Draft (individual)
Author Alexey Melnikov 
Last updated 2015-12-19 (latest revision 2015-06-17)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This memo defines an extension to the SMTP (Simple Mail Transfer Protocol) service whereby message metadata (such as Trace header fields, IMAP flags, Keying material, etc) can be transferred in separate containers similar to BDAT (RFC 3030, SMTP CHUNKING) command. This allows clean separation of transaction related state from the message itself.


Alexey Melnikov (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)