I just noticed this in SASL_README
(
http://www.postfix.org/SASL_README.html#client_sasl_enable): * The Postfix SMTP client does not support the obsolete "wrappermode"
protocol, which uses TCP port 465 on the SMTP server. See
TLS_README for a
solution that uses the stunnel command.
I believe this is out of date as wrappermode has been available for smtp
for some time now and submissions is a thing now so the protocol is no
longer obsolete either.
Peter