Configure your mail server to forward all outbound e-mail to the Sendio ESP. The feature is often referred to as “forwarding to a smart host”. Please refer to documentation for your e-mail server for instructions on how to configure and enable smart hosting.
To set up the Sendio ESP to provide outbound e-mail processing navigate to Console (SSH) Interface > Network Configuration > Sender Host Addresses and enter the internal IP address of you e-mail server.