On Sat, 17 Sep 2005 00:21:10 +0100, John C Klensin <john+smtp(_at_)jck(_dot_)com>
--On Friday, 16 September, 2005 12:38 +0100 Paul Smith
BUT, the consensus here is that you should NOT accept the
message and then send back a bounce later. So, you need to
analyse it at place of entry if possible.
Paul and others,
FWIW, at least part of what you are seeing as consensus involves
a number of us sitting back in astonishment that this discussion
has gone on as long and as far as it has.
I agree that there's not consensus in the concept of a 'keep alive' system.
But, I haven't seen anyone really advocate switching to using accept and
bounce instead of immediate reject - because of the forged email address
issue, and subsequent back scatter.
From my reading of messages here, there need to be several things in RFC
- a reduction of the recommended timeout values, eg for the post-DATA
timeout to be reduced to 1 minute - IF that is what people want, again as
it *seems* to be here. (Remember, in all this discussion, no one has
requested that the suggested timeouts in 2821 be increased, so if they
were used, 'keep alives' wouldn't be needed).
- a clarification that any checks for RFC 2821 timeouts should be the time
until the final reply code, not continuation reply codes.
- a discussion of accept/bounce later cf reject immediately, and
consequences of using either technique
- a discussion of what to do with time consuming email validation
techniques (eg reject immediately, quickly, and then either accept/bounce
or accept/discard later, depending on trustworthyness of sender email
- a clarification that continuation reply codes should be consistent with
the final reply code.