This article describes setting SSL for postfix & dovecot. https://cyberpanel.net/docs/2-ssl-for-postfix-dovecot/
A requirement is that the RDNS for the server's IP is the same domain name used for the mail server. Since I have to pick from a drop-down of available domains in Cyberpanel, that seems to imply I have to create a 'website' in Cyberpanel and also setup RDNS for that domain?
Is it correct to assume that I will be picking a domain name for my server which can be the RDNS and also have that a website in cyberpanel even if it is only dedicated to email?