Interworx Allowing SMTP Relay?

Have seen some ancient threads that say the contrary, but just want confirmation for v4.8.3 – with authentication mode “SMTP Auth available, TLS optional” – this does NOT allow relaying, correct?

In other words, there must be a POP or IMAP authentication prior to being able to relay email through the mail server.

netstat -an | grep 25
shows pakistan, china and friends connected via smtp. Whether or not they’re allowed to do anything, I don’t know.

Is the mail server secure out of the box, or do I have to do some tightening up? Would really prefer not finding my server on an SBL.

All relay tests I performed on a bare install failed:

I’d assume that language means tls/ssl is available but isn’t mandatory, and that smtp-auth is mandatory. Obviously you can still run into issues with stolen usernames and passwords, or people signing up with you with stolen CCs for the express purpose of blasting spam out of your server. I usually handle that with postfix and policyd for outbound mail - that’s my plan for our yet-to-go-live cluster as well.