If you want, I can produce a ready-to-use pmta.conf tailored to a specific server IP, sending volume, and vMTA setup — provide the server IP(s), desired max concurrent deliveries, and domain(s)/DKIM keys.
You can use telnet or a tool like swaks to send a test email through port 25. powermta 60r3 install
Place files in /opt/pmta or /usr/local/src for installation. If you want, I can produce a ready-to-use pmta