Re: [exim] Using DEFER instead of DENY or DROP for spam

this is indeed what I do. The real benefit is that a relatively
simple script can be used to show what messages have been rejected
multiple times (same pair sender/recipient), and (some) false
positives will be amongst those.
The main drawback is that you cannot let a genuine sender know that
there are problems with they server, short of sending a report
manually or automatically denying at the Nth attempt.
It cannot be used at the DATA phase as the bandwidth cost is potentially high.

g