Eduardo M . Stelmaszczyk:
> > If your Postfix is sending lots of DSN NOTIFY=SUCCESS messages for
> > SMTP mail, turn off DSN on the SMTP daemon. One example from
> > http://www.postfix.org/DSN_README.html shows this:
> >
> > /etc/postfix/main.cf:
> > smtpd_discard_ehlo_keyword_address_maps =
> > cidr:/etc/postfix/esmtp_access
> >
> > /etc/postfix/esmtp_access:
> > # Allow DSN requests from local subnet only
> > 192.168.0.0/28 silent-discard
> > 0.0.0.0/0 silent-discard, dsn
> > ::/0 silent-discard, dsn
> >
> > Another option is
> >
> > /etc/postfix/main.cf:
> > smtpd_discard_ehlo_keywords = silent-discard, dsn
> >
> > meaning don't send DSN NOTIFY for anyone.
> >
> > DSN was added long after the synchronous tls_flush() client
> > which was not designed for high volume.
> >
> > Wietse
>
>
> I would disable DSNs if I could, but unfortunately I'm not allowed to do
> that since it's a service the users need.
Will it make a difference if you allow DSN requests from local
subnet only, or does that not really differ from "don't send DSN
NOTIFY for anyone"?
Otherwise, this is going to require a source code change, for
example, making the trace_flush() function non-blocking, and
that takes a lot of testing.
Wietse
