[Mimedefang] Milter failure processing Read and Delivery Receipts

[Kris Deugau]

Michael Sims wrote:
> Your log files are showing the envelope sender, which is not always
> the same as the address in the From header.  Read receipts (or
> disposition notifications or whatever you want to call them) are sent
> using a null (<>) envelope sender for the same reason that delivery
> status notifications are sent with a null sender, to prevent mail
> delivery loops.

They may be sent with a null envelope if it's generated by the server
(you *can* specifically request such a notification), but I checked on a
few of the receipts I have in the support inbox I read here, and none of
them use the null envelope- they ALL use the recipient's real email
address.

I can't think of any reason an MUA should use a null envelope, and in
fact I've found a case where it causes more problems- users who are
running a spam filter on their system that replies to spam!  The reply
ends up stuck on your server, occupying resources.  IMHO, users should
NEVER send email with a null envelope from a client system- bounces will
never reach them.  (Instead, the bounce annoys their postmaster.)

-kgd
-- 
"Sendmail administration is not black magic.  There are legitimate
technical reasons why it requires the sacrificing of a live chicken."
   - Unknown