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Exchange Organization Split to muplitple Entra ID
We're looking for information on a project that involve splitting an Exchange organization, due to company spin-off, into 2 indipendent Entra ID tenants.
At the moment the exchange on premise is 2 node Exchange 2010 DAG.
The exchange server Org is authoritative for several mail domains.
The cut-over of the company is planned to be done by fully replicating the environment, in terms of AD and servers, and then start the new company by "cleaning" all the objects not relevant.
In this scenario is also needed to plan for exchange ORG split accordingly and setup a O365 hybrid environment for each company.
The plan being considered is as follows:
Before Company cat-over
- setup 2 AADC on the On-premise domain and configure them to make a filtered Sync to the two independent ENTRA ID of the two company.
this scenario is supported as per the Microsoft Entra Connect: Supported topologies - Microsoft Entra ID | Microsoft Learn
- Setup the hybrid exchange configuration between the Exchange 2010 DAG servers and the 2 Tenants
THIS is the first point we'd like to check for feasibility. Is it possible to configure a hybrid exchange environment with 2 Tenants?
After the companies cutover on each site we will clean up the non relevant AADC and users and exchange configuration.
Any thought or idea is welcome.
- Exchange 2010 is out of support and Microsoft have actively started blocking mail flow from this version, so you will need to move to at least Exchange server 2016 (2019 is recommended)
This update indicates it's supported by Microsoft: https://techcommunity.microsoft.com/t5/exchange-team-blog/september-2020-hybrid-configuration-wizard-update/ba-p/1687698
This site provides some details on doing it https://technicallypossible.com/index.php/2021/01/01/single-on-premises-exchange-to-multiple-office-365-tenants/
You'll be best to use a 3rd party tool to migrate data from the original tenant to the new divestiture tenant. This type of migration will probably involve some large impacts for the users you are migrating to the new tenant.
- Hello DAN,
thanks for the information, can you confirm also that an exchange 2016 server is not required to make an hybrid configuration with exchange 2010 and exchange online ?
thanks- Exchange 2010 is out of support and Microsoft have actively started blocking mail flow from this version, so you will need to move to at least Exchange server 2016 (2019 is recommended)
