Wietse Venema:
> Birta Levente:
> > On 21/02/2014 15:44, Wietse Venema wrote:
> > > The behavior that you seem to prefer (throttle down
> > > domains after 4XX reply to "MAIL FROM") is really a bug in the
> > > Postfix SMTP client implementation.
> > >
> > > Postfix normally does not throttle down domains after 4XX reply to
> > > "MAIL FROM". The bug is that Postfix treats server-side disconnect
> > > after 421 reply as a "lost connection" error.
> > >
> > > So you should not rely on this old bug forever. It will eventually
> > > be fixed.
> > >
> > Get it.
> > Thank you
>
> Moreover, snapshot 20140219 does not change anything: the test that
> I added is a NOOP. Thus, the 20140219 SMTP client behaves the same
> way as the 20140209 client.
I have fixed this. The postfix-2.12-20140223 SMTP client will not
fall back to plaintext when the message (or all recipients) was
bounced or deferred during the TLS session. It falls back to plaintext
only when delivering old mail.
This makes the SMTP client's behavior similar to snapshot 20120109,
at least for new mail that is deferred with 421 in response to MAIL FROM.
> With future releases, the SMTP client won't throttle down the
> destination when the last MX host hangs up after sending a 4XX or
> 5XX reply to "MAIL FROM". Instead the SMTP client will handle this
> in the same way as when the server did not hang up.
This turns out to be problematic, so I won't change this for now.
Postfix should probably throttle destinations that persistently
drop connections after deferring mail. It is a strong hint that the
SMTP client is not welcome.
Wietse
