What are the differences between Active Directory and Azure AD?

Active Directory (AD) and Azure AD (Azure Active Directory) are both directory services developed by Microsoft, but they serve different purposes and have some key differences:

1. On-Premises vs. Cloud-Based: Active Directory is an on-premises directory service that is installed and managed within an organization’s own network infrastructure. Azure AD, on the other hand, is a cloud-based directory service provided by Microsoft as part of the Azure cloud platform.

2. Authentication and Authorization: Active Directory primarily focuses on user authentication and authorization within an organization’s on-premises network. It provides features such as user and group management, single sign-on, and group policy management. Azure AD extends these capabilities to the cloud, allowing users to authenticate and access resources across cloud-based applications and services.

3. Integration with Cloud Services: Azure AD is tightly integrated with various Microsoft cloud services, such as Office 365, Azure, and other SaaS applications. It provides seamless single sign-on and user management across these services. Active Directory, being on-premises, does not have the same level of integration with cloud services.

4. Identity Management for Hybrid Environments: Azure AD supports hybrid identity scenarios, allowing organizations to integrate their on-premises Active Directory with Azure AD. This enables users to have a single identity across both on-premises and cloud resources, providing a unified identity management solution.

5. Scalability and Maintenance: Azure AD is a fully managed service provided by Microsoft, which means that Microsoft handles the infrastructure, scalability, and maintenance of the service. Active Directory, being on-premises, requires organizations to manage and maintain their own infrastructure.

In summary, Active Directory is an on-premises directory service primarily focused on user authentication and authorization within an organization’s network. Azure AD is a cloud-based directory service that extends these capabilities to the cloud, providing identity management and access control for cloud-based applications and services. Azure AD also offers integration with various Microsoft cloud services and supports hybrid identity scenarios.