Understanding Forest vs Domain Functional Levels
Q: Explain the difference between a forest functional level and a domain functional level, and why each is relevant to an Active Directory environment.
- Active Directory
- Senior level question
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The difference between a forest functional level (FFL) and a domain functional level (DFL) in Active Directory primarily lies in the scope and the features that are available at each level.
A domain functional level is specific to a single domain within the Active Directory forest. It determines the available Active Directory features and capabilities for all domain controllers in that particular domain. The functional level can be raised based on the version of Windows Server running on the domain controllers. For example, if all domain controllers in a domain are running Windows Server 2016, the domain functional level can be raised to Windows Server 2016, unlocking new features like Privileged Access Management and better support for cloud integrations.
In contrast, the forest functional level is broader and applies to the entire Active Directory forest, which can contain multiple domains. It establishes the capabilities available across all domains in the forest. Similar to the DFL, the FFL can be raised based on the Windows Server versions running on the forest's domain controllers. For instance, if the forest functional level is raised to Windows Server 2019, this would enable features like improved support for hybrid identities and enhanced security features such as Windows Defender for Active Directory.
Both the FFL and DFL are relevant to an Active Directory environment because they determine the feature set, functionality, and interoperability of various components within Active Directory. Raising these levels can help organizations take advantage of new features as they upgrade their infrastructure. However, it’s essential to consider compatibility with older domain controllers, as raising the functional levels is a one-way operation and cannot be reverted once done.
For example, when tight integration with Microsoft 365 is desired, raising the forest functional level to support certain Azure AD features may be necessary, which can be planned based on the organization's upgrade roadmap to ensure all domain controllers are compatible.
In summary, the DFL governs the features available within a single domain, while the FFL controls what features are available across the entire forest. Each plays a crucial role in managing and enhancing the capabilities of an Active Directory environment.
A domain functional level is specific to a single domain within the Active Directory forest. It determines the available Active Directory features and capabilities for all domain controllers in that particular domain. The functional level can be raised based on the version of Windows Server running on the domain controllers. For example, if all domain controllers in a domain are running Windows Server 2016, the domain functional level can be raised to Windows Server 2016, unlocking new features like Privileged Access Management and better support for cloud integrations.
In contrast, the forest functional level is broader and applies to the entire Active Directory forest, which can contain multiple domains. It establishes the capabilities available across all domains in the forest. Similar to the DFL, the FFL can be raised based on the Windows Server versions running on the forest's domain controllers. For instance, if the forest functional level is raised to Windows Server 2019, this would enable features like improved support for hybrid identities and enhanced security features such as Windows Defender for Active Directory.
Both the FFL and DFL are relevant to an Active Directory environment because they determine the feature set, functionality, and interoperability of various components within Active Directory. Raising these levels can help organizations take advantage of new features as they upgrade their infrastructure. However, it’s essential to consider compatibility with older domain controllers, as raising the functional levels is a one-way operation and cannot be reverted once done.
For example, when tight integration with Microsoft 365 is desired, raising the forest functional level to support certain Azure AD features may be necessary, which can be planned based on the organization's upgrade roadmap to ensure all domain controllers are compatible.
In summary, the DFL governs the features available within a single domain, while the FFL controls what features are available across the entire forest. Each plays a crucial role in managing and enhancing the capabilities of an Active Directory environment.