Hannah Schroeter wrote:
Where is it really defined that .forward style forwarding
w/o envelope rewriting is *not* correct (best some RFC
source)?
It's hidden in STD 10, discussed in MARID and ASRG recently:
<http://article.gmane.org/gmane.ietf.mxcomp/5455>
<http://article.gmane.org/gmane.ietf.asrg/10064>
"Not correct" doesn't cover it, it's only the fact that there is a 551
error code (as an alternative to 251), and the one
sentence: "The first host in the <reverse-path> should be
the host sending this command" (i.e. MAIL FROM).
Why should SPF impose effort on non-SPF sites instead of
do the effort themselves
It doesn't. If the receiver does not like SPF all he has to
do is to ignore SPF. And if he likes SPF he has to do it at
his border MTA, not somewhere else (later in his routing).
The most simple case where SPF _apparently_ breaks forwarding
is a primary MX doing SPF tests, and a secondary MX sending
all it gets to the primary MX: FAIL, unless the secondary MX
is whitelisted.
In other words if the receiver does nothing or does it right
it works. Otherwise he has to fix it, it is his mail setup.
Bye, Frank