> John's example is actually a perfect illustration of the context for my
original question. The server in question was using 450 replies to RCPT in
order to get separate deliveries of the same message for recipients with
different content filter settings.
OK, I have to admit, that's not a case I've heard of before, and it makes this
quite a bit trickier than I first thought: A server deliberately using
temporary failures in order to force the client to split the message up.
(Recipient limits in general can have this effect, but this is not
normally the
intent of such settings.) As long the the number of possible content filter
settings is small (2) this actually works acceptably well, but the fact that N
separate policies among the recipients of a given message will require N-1
retries makes this impractical in situations with lots of possible filter
settings.