Migration & CoexistenceHybrid Exchange Configuration

Hybrid Exchange Configuration

30 mins

Understanding the Concept

Hybrid Exchange configuration creates coexistence between on-premises Exchange Server and Exchange Online. The Hybrid Configuration Wizard (HCW) automates the setup of connectors, certificates, and federation trusts.

Key hybrid features include free/busy sharing between cloud and on-premises users, cross-premises mailbox moves, unified GAL (Global Address List), and shared namespace with centralized mail routing.

Azure AD Connect synchronizes on-premises Active Directory with Azure AD, enabling single sign-on and directory synchronization. Password hash sync or pass-through authentication provides seamless authentication.

Key Points

•HCW automates hybrid configuration setup

•Requires Azure AD Connect for directory synchronization

•Shared namespace allows unified email routing

•Free/busy sharing works across environments

•Cross-premises mailbox moves use MRS (Mailbox Replication Service)

•OAuth authentication enables secure cross-premises communication

Why This Matters

Hybrid Exchange is the most common enterprise deployment model, allowing gradual migration while maintaining full functionality. Understanding hybrid configuration is essential for enterprise messaging administrators.

Common Mistakes to Avoid

✗Not running HCW updates after Exchange cumulative updates

✗Misconfiguring OAuth authentication breaking cross-premises features

✗Not planning certificate requirements for hybrid mail flow

Interview Discussion Points

💡Explain the components of a hybrid Exchange deployment

💡Describe the HCW configuration process step by step

💡Discuss troubleshooting common hybrid configuration issues

MS-203 Exam Tips

📝Know HCW prerequisites: certificates, DNS, firewall ports, Exchange version

📝Understand the difference between classic hybrid and modern hybrid

📝Be familiar with OAuth configuration for cross-premises features

Migration Methods Overview

IMAP & Third-Party Migration