822/2822 specify an extremely flexible Received-line format. At least
for 2822, this flexibility is quite deliberate.
821/2821 specify a more restricted Received-line format to be used
``when an SMTP server receives a message.'' There is no requirement that
the restricted format be used in other contexts.
Lilly is complaining about a perfectly valid Received line that has
nothing to do with SMTP. He is completely wrong when he asserts that
``from'' and ``by'' are required in all Received lines.
---D. J. Bernstein, Associate Professor, Department of Mathematics,
Statistics, and Computer Science, University of Illinois at Chicago