der Mouse wrote:
   But moreover,
believe it or not I've found a fair number of servers
 that take the temporary rejection as a permanent one and never try
 again.  Customers won't accept this. 
Customers have no choice.  Greylisting is not the only thing that can
produce a temporary rejection...unless you're running a very
exceptional MTA! 
 
Yes - i find it hard to believe that an smtp mta would not 'store and
forward'.  At the very least it it would be non-compliant with RFC's and
worse it would be quickly deamed "very broken".
people have multiple mx's for a reason - servers go down.
 > Yes, I know it's easy to say in an ivory tower
mentality "well,
> that's their fault", but in a business setting we don't have the
> luxury of the ivory tower. 
I understand, and agree, but at some point (about now) the volume of spam
gets to be 100x the volume email and something has to be done.
I just turned on greylisting (two different versions, one for each mx)
on a domain and the volume of spam went down 90%.  I am willing to pay a
1 hour tax for that relief.  The time I was wasting was costing me
money.  Plus, I whitelist domains I do business with.
(at some point it becomes an economic issue where the lost time and
messages ends up costing you money.  not very ivory tower to me.)
-brad