Bart Schaefer <schaefer(_at_)brasslantern(_dot_)com>:
What I disagree with is the claim that the *sending* system is in violation
of RFC2821 because the return-path has become invalid. Put another way, I
don't agree that RFC2821 *justifies* your refusal of the message, merely
that it does not *prohibit* such refusal.
You are correct. The path may *become* invalid without putting the
sending MTA retroactively in violation. It must however *be* valid
at time of transmission. That is the plain meaning of 4.1.1.4.
Yakov's point (unless I'm completely confused) is that it would constitute
a new requirement for *sending* systems if the return-path "MUST" always be
a valid address. Hector says that it would not be a new requirement, and I
still haven't been convinced that Hector is correct.
Yakov is correct that that would be a new requiremwnt. But "MUST
always be a valid address" is not what I am maintaining, nor is it
Hector's position unless I have misunderstood him.
We are simply maintaining that sending MTAs MUST issue a valid return
path at time of transmission.
--
<a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>
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