sender address of reject messages

Daniel Nilsson dnilsson at
Mon Aug 18 21:08:54 EDT 2003

> -- Daniel Nilsson <dnilsson at> is rumored to have mumbled on
> Montag, 18. August 2003 15:59 Uhr -0400 regarding sender address of
> reject  messages:
>> I noticed that I can set the sender address of the reject messages in
>> imapd.conf using the postmaster: parameter. Is the correct solution to
>> this problem to set the postmaster: to rejected or something like that
>> doesn't corresspond to a real user or alias on our domain ?
> Yes, I think it is. We use doublebounce, which is aliased to /dev/null,
> for  these purposes ...


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

I guess what cyrus does in this case is pretty much equal to this if I
understand correctly:

/usr/bin/echo "From: doublebounce at\nTo:
non-existant-user at\nSubject: Test\n\nBody of the message" |
/usr/lib/sendmail -f '<>' -- non-existant-user at

This message will be returned to the local postmaster by sendmail on the
local machine, it will not bounce to doublebounce at

I'm not clear why the sieve reject messages have -f <> hardcoded, can
someone help me to explain that ?

Daniel Nilsson
Signal Integrity Software Inc.

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