Tony Hansen wrote:
A server MAY attempt to verify the return
path before using its address for delivery notifications, but
methods of doing so are not defined here nor is any particular
method recommended at this time.
How do we reconcile that with:
... the protocol requires that a server
MUST accept responsibility for either delivering a
message or properly reporting the failure to do so.
If a server verifies the return path and decides not to use it, what
constitutes "...properly reporting the failure" to deliver a message?
Regards,
David.