I wonder if your work on SMTP message tracking would be
directly applicable to OPES requirement to track OPES services.
It looks to me that OPES processors or services could use MSGTRK
protocol to relay information about OPES adaptations performed on the
message. We would probably have to define some OPES extensions for
Per-Message MTSN Fields (Section 3.2 in draft-ietf-msgtrk-trkstat-05),
right?
For example, we could define an extension field to list identifiers of
OPES services that touched the message while it was in transit through
an OPES MTA. Or am I completely off-track here?