Searching the Web produces many articles offering Best Practices for naming the Active Directory Domain on a local LAN.
The prevailing sentiment seems to be to use a subdomain of the entity's primary FQDN. For example, the company widget.com might have an AD domain of ad.widget.com or corp.widget.com. The LAN AD would use a unique subdomain of the primary FQDN.
My question has to do with Exchange in the above setting. It seems that the recommended configuration for Exchange is to use Split-Brain DNS (split DNS). Unless I am misunderstanding this, that would suggest that I should name the local LAN widget.com (rather than ad.widget.com or corp.widget.com).
I would like to better understand the pro's and cons of choosing to configure my AD Domain as a subdomain (e.g. ad.widget.com), and the impact on deploying an on-premisis Exchange server in that environment.