<virtual-mta ipv4_only> bind-ip 203.0.113.5 only # 'only' flag forces IPv4 </virtual-mta>
Whether you are a legacy email architect or a curious technologist, understanding PowerMTA 60r3 gives you lasting insight into the mechanics of internet-scale email delivery—mechanics that, despite all the cloud buzz, still run on . powermta 60r3
Captures rejected attempts along with the exact SMTP response code and error string returned by the receiver. <virtual-mta ipv4_only> bind-ip 203