sender address of reject messages

Rob Siemborski rjs3 at
Tue Aug 19 10:10:24 EDT 2003

On Mon, 18 Aug 2003, Daniel Nilsson wrote:

> I played around with this for a while, and I was able to make cyrus change
> the header of the reject message to be doublebounce at But from
> looking at the source of cyrus, it seems like the from address in the
> envelope of the reject message is set to <> (lmtpd.c lines 502-503 in
> cyrus-imapd 2.0.16). I guess what happens then in my case is that the
> reject messages have an empty envelope from: address and when the spammers
> domain MTA doesn't want to receive the message from our mail server (since
> the user doesn't exist for example) sendmail decides to alert the local
> postmaster.

>From RFC 2821:

   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:<>

Also from draft-moore-auto-email-response-02.txt:

   The primary purpose of the MAIL FROM address is to serve as the
   destination for delivery status messages and other automatic responses.
   Since in most cases it is not appropriate to respond to an automatic
   response, and the responder is not interested in delivery status
   messages, a MAIL FROM address of <> MAY be used for this purpose.

This is of course slightly more applicable to reject than it is to
vacation, but I don't see a strong argument why they should be treated
very differently.

I also don't see a strong argument to set a return-path to a nonexistant
account when a null Return-path should already solve that problem in a
general way. Though draft-moore-auto-email-response-02.txt does go on to

   A MAIL FROM address which is specifically chosen for the purpose of
   sending automatic responses, and which will not automatically respond to
   any message sent to it, MAY be used instead of <>.

So perhaps it is reasonable to have this be configurable (we need to work
on how we build the sendmail command line for Exim anyway).


Rob Siemborski * Andrew Systems Group * Cyert Hall 207 * 412-268-7456
Research Systems Programmer * /usr/contributed Gatekeeper

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