Azure AD pass-through authentication provides an alternative to the Azure AD password hash synchronization and a local ADFS infrastructure if all claims-based applications are connected to the Azure AD. Microsoft offers with this service the capabilities to reduce the on-premise complexity and operations of ADFS. Furthermore, in combination with the password hash synchronization, customers get a redundant and flexible authentication environment. You are also able to include password protection features for your local Active Directory.

Pass-through authentication supports the Azure AD conditional access policies, Azure MFA, and the blocking of legacy authentications to secure your organization's or customer environment. The communication of the on-premise agent and the Azure AD service is protected with certificate authentication. The feature can support multi forest infrastructures if forest trusts are enabled and the UPN-suffix routing is configured...