Jaroslaw Rafa: > Dnia 23.12.2020 o godz. 09:32:31 @lbutlr pisze: > > > > The recommendation for years has been to use port 587 (submission) for > > STARTTLS and to never use port 25 for anything but server-to-server > > communication. > > And server-to-server communication nowadays uses STARTTLS, doesn't it?
Indeed.
smtp/25 MTA to MTA, STARTTLS usually optional
smtps/465 MUA to MTA, TLS wrappermode (mandatory TLS)
submission/587 MUA to MTA, STARTTLS usually required
Wietse
