What should organizations create if they are using a hybrid Exchange Server?

In the context of using a hybrid Exchange Server, creating a write-back scenario in Okta is the most suitable approach. This configuration allows for the synchronization of specific attributes or policies from your cloud-based identity management system back to your on-premises directory. By implementing write-back, organizations can ensure that changes made in the cloud are reflected in the on-premises Active Directory. This is crucial for maintaining consistency between cloud and local identities, especially in hybrid environments where both on-premises and cloud resources are utilized.

The other options do not fit as effectively for hybrid Exchange scenarios. For instance, establishing a universal sync setup might not adequately address the unique needs of a hybrid environment, particularly regarding attribute synchronization. An in-cloud Global Administrator account is also more about administrative access rather than addressing the functional integration of identities across environments. Lastly, a full federation of the domain could lead to complexity and is typically not necessary for simply managing identity synchronization in a hybrid setup.

Thus, a write-back scenario provides a seamless method for ensuring that identity information flows correctly between on-premises and cloud systems, which is essential for the effective management of a hybrid Exchange Server environment.