We are undergoing the process of moving to an Office 365 solution from a single 'domain'.local domain. I have already validated our routable 'domain'.com domain.
We are about to install Azure AD Connect to synchronize user accounts to our Azure AD presence. I understand that AD UPN's must use a routable domain and that as changing our primary AD domain (from .local) is not an action we want to take there is an option to update as following;
1) Add 'domain.com' as an Alternate UPN suffix (Domains & Trusts - applied only at new account creation)
2) Change the UPN suffix for existing users (to the routable 'domain'.com), or
3) Use PowerShell to change the UPN suffix for all users.
My questions are;
1) Has anyone used this, or another process
2) What has been the positive (or negative) experience
3) What are the risks involved
My challenge is that as Microsoft have changed the tools for synchronizing (eg from DirSync etc) it is difficult to find consistent and relevant information.
Thanks in advance.