- Login ECP Panel > Mail flow > Receive connectors > Add a New Connector
- Select Frontend Transport and type is Custom
Authentication enables “Externally secured (for example, with IPsec)
Permission Group enable “Exchange Servers”, “Partners” and “Anonymous users”
- Remote network setting:
add which IP address allow relaying the email
- Under accepted domains, you can add another domain for the relay, else you only can using by default domain for the relay.
Remark: When you using another domain for the external relay, please also check the SFP record, make sure the SPF record has included this SMTP server IP, so the outgoing e-mail will not classify as spam e-mail.