Frank Ellermann wrote:
Hi, on the DKIM list a poster claimed that Sender is OPTIONAL.
Looking for the evidence why that's wrong in 2822upd I found
an unclear SHOULD:
1: from multiple authors => MUST (table 3.6 and in 3.6.2)
2: one author = transmitter => SHOULD NOT (redundant, 3.6.2)
3: otherwise SHOULD (3.6.2)
I don't get case (3), why is it only a SHOULD ? For anything
that's not covered by (2: one author = transmitter) I'd expect
a MUST:
- Otherwise, both fields SHOULD appear.
+ Otherwise, both fields MUST appear.
What could be a plausible excuse to ignore the SHOULD in (3) ?
Nothing wrong with the statement in 2822 section 3.6.2:
If the originator of the message can be indicated
by a single mailbox and the author and transmitter are identical, the
"Sender:" field SHOULD NOT be used. Otherwise, both fields SHOULD
appear.
-1 only trying to change something that isn't broken and on enforcing
something that will immediately make existing systems non-compliant for
no reality plausible reason.
--
HLS