With both capability and failure notification, we concluded that there had to
be a third party to get extensions from and to make notes of failure on. It
was noted that due to the nature of the game, we were doomed to
having a third
party (not delivery server, not client) that holds extension and failure
information;
This does not have to be a third party. The Sieve execution agent
can implement just enough ACAP to allow clients to access and store
scripts, and get capability and warning/error info.
Envelope-matching command should take similar commands to address match:
:localpart / :domain / :all
This also requires parts of an 822 parser, but less of them (see above).
Well, an 821 parser if the actual envelope is still around or has
been passed to the Sieve execution agent.