On Sun, Oct 01, 2017 at 07:15:36PM +0200, Matus UHLAR - fantomas wrote:
> > The remote mailserver is configured to accept SSL/TLS on port 587. This is
> > proven to work since user mail clients successfully directly connect to
> > hmailserver using the related port with SSL/TLS.
>
> tried
> http://www.postfix.org/postconf.5.html#smtp_tls_per_site
A long-deprecated feature (since Postfix 2.3 over a decade ago).
The non-deprecated interface is:
http://www.postfix.org/postconf.5.html#smtp_tls_policy_maps
http://www.postfix.org/TLS_README.html#client_tls_policy
And while requiring TLS is a good idea, it won't work if even
opportunistic TLS fails to produce a TLS connection.
The OP has posted scan concrete evidence, just anecdotes, so
no further help is presently possible.
--
Viktor.
