Active Directory Domain Services (AD DS)
Lesson 16

Azure AD Connect

By Sai Kurada
September 19, 2023
Azure AD Connect is a Microsoft service that facilitates the synchronization of on-premises Active Directory environments with Azure Active Directory (Azure AD). It enables seamless user authentication and access to resources both on-premises and in the cloud.
Here are key points about Azure AD Connect:

Identity Synchronization:
  • Azure AD Connect allows organizations to integrate their on-premises AD with Azure AD. This ensures that user accounts, passwords, and attributes are synchronized between the two environments.
Single Sign-On (SSO):
  • By synchronizing on-premises and cloud identities, Azure AD Connect enables users to sign in once with their existing corporate credentials, providing a seamless SSO experience for accessing cloud-based services.
Authentication and Authorization:
  • Once synchronized, users can authenticate with Azure AD, gaining access to resources such as Microsoft 365 services, Azure resources, and other cloud applications.
User and Group Synchronization:
  • Azure AD Connect synchronizes user accounts, group memberships, and attributes between on-premises AD and Azure AD. This includes user principal names (UPNs), passwords, group memberships, and more.
Password Hash Synchronization (PHS):
  • PHS is a method used by Azure AD Connect to synchronize user passwords securely. Hashes of on-premises passwords are synchronized with Azure AD, allowing for password-based authentication.
Pass-through Authentication (PTA):
  • In addition to PHS, Azure AD Connect also supports PTA, which allows users to authenticate against on-premises AD without the need to synchronize passwords to the cloud.
Staging Mode:
  • Azure AD Connect offers a staging mode for testing and validation before deploying changes to the synchronization process, ensuring that the synchronization process will work as expected.
Customization and Filtering:
  • Administrators can customize the synchronization process to include or exclude specific user accounts, groups, or attributes based on their organizational needs.
High Availability:
  • Azure AD Connect can be deployed in high availability configurations to ensure continuous synchronization even if one server becomes unavailable.
Integration with Multi-Forest Environments:
  • Azure AD Connect can be configured to synchronize identities from multiple on-premises AD forests to a single Azure AD tenant, allowing for complex enterprise environments.
Custom Installation Options:
  • Administrators can choose different installation options based on their specific requirements, such as choosing the authentication method (PTA, PHS, or ADFS), customizing sync rules, and more.
Automatic Upgrades:
  • Azure AD Connect receives regular updates and new features from Microsoft. The tool can be configured to automatically download and apply these updates.


Azure AD Connect is a crucial tool for organizations looking to integrate their on-premises AD environments with Azure AD. It provides the foundation for a unified identity and access management experience across both on-premises and cloud-based resources.