In order to activate the Mail Security relay feature, send an email to the following address: email@example.com. Ask Support to add the required IP address to Relay.
In your customer Exchange server, setup the following server in the Exchange smart-host "smtp.ateranetworks.com"
If SPF records are required, add the following record:
"v=spf1 a mx ip4:220.127.116.11/26 ip4:18.104.22.168/24 ip4:22.214.171.124/26 -all"