Hello John
Here are the rules for how the suffix is generated.
If no idrac DNS name is populated in the network settings
Email sent as: idrac-svctag@[ip_address]
If idrac DNS name is populated, but DNS domain name is blank
Email sent as: idrac-svctag@[ip_address]
If idrac DNS name is populated, and DNS domain name is populated
Email sent as: idrac-svctag@DNSname.DomainName
If idrac DNS name is populated, and DNS domain name is set to DHCP
Email sent as: idrac-svctag@DNSname.DomainName
I hope that helps. If not let me know.
Thanks