0

I've got a new customer which already has an Azure AD sync from his on-premise active directory with Azure AD Connect. The goal is to set up a new Azure AD Connect to sync a new different on-premise AD to the existing Azure AD. The customer is using Exchange Online primarily.

Is there anything I need to keep in mind beside having the same UPN for the users in the new onprem AD or has someone done such a migration before?

Unfortunately I didn't find any usefull informations yet for that specific topic.

Luca Marohn
  • 1

1 Answers1

0

It's not clear to me what you're trying to accomplish. Are you trying to sync users in a new on premises Forest/Domain to existing Azure AD users that were synced from a different on premises Forest/Domain?

You cannot have more than one Azure AD Connect instance syncing to one Azure AD instance. You can sync multiple on premises Forests/Domains to Azure AD with a single Azure AD Connect instance. The Azure AD Connect instance needs only network connectivity and DNS name resolution between the on premises Forests/Domains. No Forest/Domain trust is required.

https://docs.microsoft.com/en-us/azure/active-directory/hybrid/plan-connect-topologies

The users in the new Forest/Domain don't need to have the same UPN as the users in the existing Forest/Domain. They only need to have a UPN that matches one of your verified domains in Azure AD.

Forest/Domain A = user@contoso.com

Azure AD Verfified Domain A = contoso.com

Forest/Domain B = user@example.com

Azure AD Verified Domain B = example.com

joeqwerty
  • 109,901
  • 6
  • 81
  • 172
  • I would like to sync a new forest/domain to an existing Azure AD and retire the old one. Basically what I would like to know is how to accomplish the migration and if there's anything special to pay attention for. ex. new user A get's synched with his existing azure user and it doesn't create a duplicate because there's already an user A in the azure AD. – Luca Marohn Aug 19 '20 at 11:25