We are re-designing a customer's AD and based upon the following I was hoping to get some feedback/thoughts.
Microsoft Best Practices for TLD is not to use .local, but use a sub-domain of the public external domain name. So if the domain name is somedomain.com, the root forest tld would be ad.somedomain.com
Company Structure is that there is an umbrella Management Group ("CompanyGroup") which owns/operates multiple companies ("CompanyA","CompanyB"). Currently all networks are individually configured using companyA.com and companyB.com as their own internal TLD.
CompanyGroup does not own any public domain names, nor do they use email or any other service attached to their CompanyGroup name - they operate under each CompanyA, CompanyB
Office 365 integrated with DirSync on the horizon as well - I read that it is worth having this correct and matching domain names of email as well
My thought was to configure a TLD such as ad.companygroup.com once I was able to purchase a new domain name for CompanyGroup but do I need it? I mean, if CompanyGroup is not being used anywhere should I use ad.CompanyA.com as the Forest Root and then add ad.companyB.com as a new tree?
Ideally we will try and migrate as much as possible from existing AD but happy to start over if it means a well designed AD.