On 03/04/2019 13:45, Wietse Venema wrote:
Matus UHLAR - fantomas:
Marco:
The only exception is the recipient "mailer-dae...@example.com", where
let suppose example.com is a local domain.
On 03.04.19 07:16, Wietse Venema wrote:
MAILER-DAEMON is special. Postfix sends mail mail from <> as
MAILER-DAEMON@$myorigin and accepts mail for MAILER-DAEMON (or
whatever empty_address_recipient says).
is there a reason to accept replies to DSNs, which should not be replied to?
So as not to make a bad situation worse. This may be an unnatuural
approach for some people. When the shit hits the fan, don't throw
it back, just get rid of it.
Wietse
This leads me to a question I have.
In my environment I have external SMTP servers (sendmail), these servers
accept email from external sources outside of my environment, runs
Anti-Virus and Spam protection and if these pass they forwards the mail
onto an internal SMTP server (postfix) which handles the local mailboxes
(for dovecot IMAP). If the external servers result in a reject 50x error
(because of spam or virus), I don't have to care whether someone gets a
MAILER-DAEMON reply, because my servers didn't send it we just rejected
it during the SMTP session.
I notice that some mails that pass the sendmail server get rejected by
postfix, because the sender domain appears to be NXDOMAIN. I assume
these are temporary 400 rejections (to cope with a failed DNS) -
Sendmail keeps these in the queue for a number of days and eventually my
postmaster receives a NDR - the NDR can't be sent to the originator
because the reply email is not valid anyway.
The email that result in NXDOMAIN are usually mis-configured
mailing-lists, and my users would probably want to receive these email,
they're because the mailing-list sender has made a mistake (i.e. they've
used no-re...@churchhouseinnmarldon.co.uk, instead of their actual
domain churchhouseinnmarldon.com). Incidentally
postmas...@churchhouseinnmarldon.com doesn't exist either, and whois
information leads to an anonymous web form which doesn't appear to be
monitored.
What postfix configuration can I perform to allow postfix to ignore this
mis-configuration on the remote sender part, or what sendmail
configuration can I put in to reject with 50x error when it is talking
with the mailing-list software, which I would assume then that the
mailing-list operator might discover their error...
