Philip,
There is some work going on currently regarding an XVERP extension to
ESMTP.
The basic idea is that VERP is good since it allows more reliable
identification of bouncing addresses for mailing lists, but bad since it
requires each message to be sent in a different envelope.
XVERP tagged onto the end of a RCPT TO allows the address to be marked
as being associated with a VERP type delivery, and can optionally also
specify the VERP mangling characters.
Of course any transformation of the recipient address (rewrite etc)
probably needs to preserve the original address for use as the VERP
sender address....
Theres not much documentation on this right now - there is an internet
draft for something very similar - a VERP extension - which I think is
the final intention with the XVERP being used between consenting
systems.
Draft is at
http://www.courier-mta.org/draft-varshavchik-verp-smtpext.txt
Might be worth giving some thought to in case it breaks architecture of
the current implementation anywhere - *prior* to exim 4 release is a
better time to break architecture than after :-)
Nigel.
--
[ Nigel Metheringham Nigel.Metheringham@??? ]
[ Phone: +44 1423 850000 Fax +44 1423 858866 ]
[ - Comments in this message are my own and not ITO opinion/policy - ]
