"Meng" == Meng Weng Wong <mengwong(_at_)dumbo(_dot_)pobox(_dot_)com>
writes:
Meng> yeah, but in those cases, the return-path should match the
Meng> resender, not the original sender, so that's probably ok.
Well, it would work (after flag day) if the Eudora user's MTA didn't
add an RNAME.
If it added an RNAME according to the usual PRD algorithm, and the
original sender publishes New SPF records, then it will be rejected.
If the check is not being done at SMTP time but by, say, by
SpamAssassin, then again SpamAssassin would get the original sender as
the PRD and would mark the message as spam.
There's really not much that can be done about this; old Eudora's are
broken. Hopefully it's fixed in current versions but it would be good
to verify this.
-roy