As usual I agree with Mr. EEF:
On Aug 9, 2010, at 10:27 PM, ned+ietf-smtp(_at_)mrochek(_dot_)com wrote:
I have a somewhat different take on this. First of all, I have always thought
the admonition that you MUST minimize the amount of time spent before
responding to the trailing dot to the greatest extent possible was, well,
bunk.
(It's also an effectively unenforceable MUST - who can say you've done all you
can or not? - which is bad in its own right.) While it is important not to
spend too much time, the difference between a millisecond delay and a 2 second
delay is, in this situation, not worth worrying about.
Rejecting anything that you can at the SMTP level, rather than generating a
bounce, strikes me as a sufficiently Good Thing that it outweighs any remaining
benefits from the "MUST minimize" rule. Minimizing bounces seems more valuable
than minimizing SMTP connection time, primarily because the bounces are more
likely to waste an actual human being's time at some later point. -- Nathaniel