santosh malavade:
> Hi,
>
>
> I am trying to change the envelope sender appearing in Non Delivery Reports
> as from=<> using sender_canonical_maps hash file
According to Internet Mail Standards (RFC5321 etc.) non-delivery
reports must be sent with the null sender.
Wietse
RFC 5321
3.6.3. Message Submission Servers as Relays
...
If an SMTP server has accepted the task of relaying the mail and
later finds that the destination is incorrect or that the mail cannot
be delivered for some other reason, then it MUST construct an
"undeliverable mail" notification message and send it to the
originator of the undeliverable mail (as indicated by the reverse-
path). Formats specified for non-delivery reports by other standards
(see, for example, RFC 3461 and RFC 3464) SHOULD be used if
possible.
This notification message must be from the SMTP server at the relay
host or the host that first determines that delivery cannot be
accomplished. Of course, SMTP servers MUST NOT send notification
messages about problems transporting notification messages. One way
to prevent loops in error reporting is to specify a null reverse-path
in the MAIL command of a notification message. When such a message
is transmitted, the reverse-path MUST be set to null (see
Section 4.5.5 for additional discussion). A MAIL command with a null
reverse-path appears as follows:
MAIL FROM:<>
