OK, I'm sold; I'll use SMTP-AUTH instead of POP-before-SMTP. I can
authenticate from inside or outside the network, using SMTP-AUTH in
either PLAIN or LOGIN mode. CRAM-MD5 is apparently not implemented (yet).
I can only relay when I connect from inside the network. Attempting to
relay from outside the network gives me the error "553 sorry, that
domain isn't in my list of allowed rcpthosts."
I am not using a SQL db for the backend. Should I be seeing a file
called open-smtp? It doesn't exist.
How do I get this thing to allow me to relay from my dynamic IP address
once I've authenticated with SMTP-AUTH?
If you're using rblsmtpd, you'll need to either configure and use port
587 for submission (with no rblsmtpd but required authentication), or
install spamdyke (highly recommended).