On 3 Sep 2011, at 02:54, "Robert A. Rosenberg" <hal9001(_at_)panix(_dot_)com>
For this to work, there would need to be a list maintained by the delivering
MTA that lists which other MTAs it has tried to deliver to which failed due
to failure to connect (along with a queue of messages that need to be
delivered to that MTA and a time to next attempt to connect). When a new
message arrives and it gets delivered (since that connect attempt worked)
then the queue of pending messages can then be immediately flushed to the
MTA. How many MTAs have this type of support to force flush a pending queue
when a message delivery succeeds?
Exim works in roughly this way.
f.anthony.n.finch <dot(_at_)dotat(_dot_)at> http://dotat.at/