Hi,
At this site we've got some Exim servers which do various forms of "verify =
recipient". Our customers use our Exim servers as a "smart host". Some
customers with MS Exchange report problems with their queues filling up, which
I /think/ is triggered by the "verify = recipient" failing (i.e. throwing a 451
error code); I'm /guessing/ that Exchange treats this as some sort of
connection- or host-level error, as opposed to an error for just that
recipient, or even just that message.
Does any of this sound familiar to you?
How should an RFC-compliant MTA handle a 451 error from RCPT? I get as far as
it's a temporary error, in the "Mail system", which may mean "Requested action
aborted: error in processing". So does that mean that a compliant MTA should
drop the connection? Defer all messages for that host? Defer that message,
but continue with other messages for that host? Defer that recipient, but
continue with other recipients for that message?
Thanks,
--
Dave Evans
Power Internet
PGP key:
http://powernet.co.uk/~davide/pgpkey
