[RKDinOKC]

Port 465 is secure by default requiring TLS/SSL.
Port 587 does both insecure and secure. For secure you have to enable TLS. Supposed to be replacing port 25. So I would say not secure.

Set my mailserver so all server connections come thru the hosted anti-spam. It comes in on port 2525, an old email port.

My mail server sends on port 25, but does not receive port 25.

If you set up an smtp client it is either 465 SSL or 2525 and requires login.

That way I don't get spammers connecting on port 25.