ISSUE WITH SSL CERTIFICATE DURING CRM IFD DEPLOYMENT

good morning all,

I am trying to configure IFD fro our existing CRM.

The CRM is currently installed in a VM with a static IP within our network. so the domain is a local domain within the VM.
I need to provide a domain for issuance of SSL certificate and other configuration for claims based.

I am confused as to what domain will I put?... because the one we have is locally managed within the windows server 2012 on our VM where CRM is installed.

Please help, which wildcard domain will I specify as common name for the ssl certificate and other configuration?

Thanks very much

NB: though we have a public IP that port forward to the VM.