So, on the topic of unnecessary work... is it considered bad form to have
exim do a reverse connect on incoming mail and ensure that the sender's
address is good, then reject the message if it isn't? Or is that a bad thing
because some servers simply have sending-only addresses?
> Sure, there's no problem with sofware doing unnecessary work - that's
> what it's for :-) but the point is that you aren't telling your sender
> immediately when a genuinely bad address is used. That, IMHO,
> is wrong.