In <20040224215452(_dot_)GS27676(_at_)dumbo(_dot_)pobox(_dot_)com> Meng Weng
Wong <mengwong(_at_)dumbo(_dot_)pobox(_dot_)com> writes:
However, many MTAs have convenient facilities for envelope-time
(pre-DATA) plugins; checking the message body is a little bit harder and
will deter deployment.
Not to mention that there are broken MTAs out there that assume that
either the DATA command can't fail, or that any error means that they
should retry immediately, even if they received a 5xx reject code.
-wayne