You have installed Microsoft Teams and now realize that you can’t use it 100% because there is no access to “Calendar”? Or do you want Teams but don’t want to switch completely to the cloud? Then we have the solution for you: the Exchange Hybrid variant!

If you previously managed mailboxes with an on-premise Exchange, you need to switch to an Exchange Hybrid variant. Why? Because Microsoft Teams, as a pure cloud product, cannot otherwise communicate with your mailbox and therefore your calendar. This hybrid connects on-premise organizations with Exchange Online tenants, and establishes secure communication between these two components.

Exchange Hybrid Configuration

Exchange Hybrid Configuration

How do I make a hybrid version?

Use the Hybrid Configuration Wizard (HCW) to set up Exchange Hybrid.

To be able to use Teams with the on-premise mailbox, the Classic Full Hybrid version must be selected. This is currently the only version that allows this.

Prerequisites for being able to implement Classic Full Hybrid at all:

  • the on-premise Exchange Server must be Exchange Server 2016 or 2019, with all available updates
  • the Exchange organization must be directly accessible via the Internet using HTTPS
  • the public Exchange endpoint must be discoverable by Autodiscover
  • the on-premise Exchange Server must be able to communicate directly with Exchange Online Protection via SMTP

On the last point, communicate directly: Exchange Client Access endpoints are made public to the Internet via a reverse proxy (or similar). An official TLS certificate is used to make connections secure. The SMTP message flow connection can be established by 2 methods. Either through the Exchange Edge Transport Server on the perimeter network (DMZ; recommended variant). Or directly between local Exchange servers & Exchange Online (variant B).

Communication Exchange Hybrid

What else is there to consider?

Microsoft Teams backend services use Auto Discover V2 & Modern Authentication to discover & authenticate to your on-premise Exchange servers. This authentication method requires the configurations given HERE. These can be done after HCW has been executed.

The basis of the Exchange Hybrid version is the synchronization of the Active Directory with Azure AD Connect. Exchange Hybrid must also be enabled in Azure AD Connect.

Many already use Azure AD Connect. If not, HCW offers the possibility to install & configure an express version. However, the Tech Community advises to download and configure the latest version of Azure AD Connect manually. It is also important that a supported version of Exchange Server is always running on the Exchange Server on site. This ensures that Exchange Hybrid is stable and secure and that all Exchange features interact correctly with the on-premise environment.

Moving a company to the cloud, in whole or in part, can be difficult. As we have seen from this example alone, many problems can arise. Anyone who is currently in the discovery phase should therefore have a good advisor at their side who can guide them through this process.

If you would like to know how we can help your company, please get in touch with us. Either call us directly or leave a message using the contact form.

The information provided in this article has been translated for you by the Microsoft Tech Community.