Will adding a UPN suffix to our current DomainName.local AD environment create an issue if we eventually create a new AD environment with the Forest/Domain name of the newly added UPN suffix?
Current AD Environment:
Current AD domain: DomainName.local
Current Exchange account email domain: firstname.lastname@example.org
Current website/webpages (*externally hosted): cityname.gov or www.cityname.gov
Current AD OS Environment: 2008R2
Exchange version: 2010
routable domain name options: domain.com, domain.net, domain.gov
O365 suggests adding a UPN suffix with routable domain extension to current environment (Example: New UPN suffix: cityname.gov)
We will be redesigning/creating a new AD environment several months down the road. We want to name the new domain: Internal.CityName.gov
1. With our current environment, should I add the following UPN suffix: cityname.gov and/or internal.cityname.gov?
2. If we add internal.cityname.gov as a UPN suffix to our current environment, what issues might I face if we set our new AD domain name also as internal.cityname.gov?
3. Should I only add ‘cityname.gov’ to our current AD environment to start our AD domain with the connection to O365?