Rand Wacker wrote:
Return-Path: is a reflection of the RFC2821 MAIL FROM
address, and is entirely at the discretion of the MDA as to
whether or not to insert it.
The author of RfC 3834 used a stronger version of this problem:
| If the response is to be generated after delivery, and there
| is no Return-Path field in the subject message, there is an
| implementation or configuration error in the SMTP server that
| delivered the message or gatewayed the message outside of
| SMTP. A Personal or Group responder SHOULD NOT deliver a
| response to any address other than that in the Return-Path
| field, even if the Return-Path field is missing. It is
| better to fix the problem with the mail delivery system than
| to rely on heuristics to guess the appropriate destination of
| the response. Such heuristics have been known to cause
| problems in the past.
In other words, "Sender ID" is broken by design. Bye, Frank