Unbelievable! I changed configuration (see below).
Tell me please, need I use all of these ports? I mean 25, 465, 587 and 993.
Now I see next result:
PORT STATE SERVICE VERSION
25/tcp open smtp Postfix smtpd
465/tcp open ssl/smtp Postfix smtpd
587/tcp open smtp Postfix smtpd
So, what about port 587? Need I close it to be more secure )))
Or give me additional suggestions for securing mail.
Thank you a lot! You helped me!