Re: [exim] Deny vs. Drop

Quoting Marc Sherman:

>> Even if you know positively that the sender is a spammer, their SMTP
>> service will keep reconnecting over and over for each additional
>> message (if dropped at MAIL/DATA) or recipient (if dropped at RCPT)
>> that is still queued.
> That's true for real SMTP servers. It's false for most zombie farms,
> which typically run broken hacks that only vaguely resemble an SMTP server.

True today, but I think they will evolve eventually, so other methods
like greylisting (which I also use today on suspicious hosts) will also
get useless.
Dropping connections immediately is quite cheap (even more with
rejecting the connection on your firewall), but then one should be very
sure the sender is a zombie.