Windows Server 2025 Domain Functional Level: New Features, Benefits, and Upgrade Guide

Microsoft is set to release Windows Server 2025. It brings a big update to the Domain Functional Level (DFL) in Active Directory Domain Services (AD DS) and Active Directory Lightweight Domain Services (AD LDS). This guide will cover the main improvements, benefits, and how to upgrade to the new Windows Server 2025 DFL.

The new DFL focuses on better security, performance, and scalability. It also makes setting up domain controllers easier.

What is Domain Functional Level (DFL)?

The Domain Functional Level (DFL) sets the limits for what Active Directory Domain Services (AD DS) can do. It also decides the minimum Windows Server version for domain controllers. Upgrading the DFL lets organizations use new features and improvements from each Windows Server update.

New Features and Enhancements

The Windows Server 2025 DFL brings big improvements in security, performance, and management. Some major updates include:

• 32k database page size option for better AD DS and AD LDS scalability
• AD schema updates with new log database files (LDF)
• AD object repair capabilities for missing core attributes
• Channel binding audit support for LDAP connections
• Kerberos PKINIT support for cryptographic agility
• LDAP encryption by default and TLS 1.3 support

Benefits of Upgrading to Windows Server 2025

Upgrading to Windows Server 2025 DFL brings many benefits. These include:

1. Stronger security to protect data and user credentials
2. Better performance and scalability for big AD DS and AD LDS setups
3. Easier domain controller setup and management
4. Deeper integration with Azure Arc for hybrid cloud setups
5. Works well with the latest Windows Server versions

By using the new features and enhancements in Windows Server 2025 DFL, organizations can boost their Active Directory’s security, efficiency, and management.

Active Directory Domain Services Improvements

Windows Server 2025 has big updates for Active Directory Domain Services (AD DS) and Active Directory Lightweight Directory Services (AD LDS). One key change is the optional 32k database page size for AD. This is a big jump from the old 8k page size limit.

32k Database Page Size Optional Feature

The 32k page size brings many benefits to AD DS and AD LDS databases. These include:

• Ability to store up to ~3,200 values in multi-valued attributes, a 2.6x increase from the previous limit
• Support for larger individual AD objects, up to 32k bytes in size
• A forest-wide upgrade process to transition all domain controllers to the 32k page format

This change makes AD DS and AD LDS databases more scalable and capable. It lets organizations store more data and handle bigger objects in their Active Directory environments.

AD Schema Updates and Object Repair

Windows Server 2025 also brings new AD schema updates. These include three new Log Database Files (LDF): sch89.ldf, sch90.ldf, and sch91.ldf. These updates add new features and capabilities to AD DS and AD LDS.

The new Domain Functional Level (DFL) also lets admins repair AD objects with missing core attributes. This includes SamAccountType and ObjectCategory, as well as resetting the LastLogonTimeStamp attribute. This ensures the AD DS and AD LDS databases stay reliable and well-functioning.

“The 32k page size unlocks significant improvements, including the ability to store up to ~3,200 values in multi-valued attributes, a 2.6x increase.”

Enhanced Security Measures

The new Windows Server 2025 Domain Functional Level (DFL) brings key security updates. These updates aim to improve access control, protect sensitive data, and secure default machine account passwords.

Channel Binding Audit Support

Windows Server 2025 DFL introduces channel binding audit support. This feature helps enforce stronger security for LDAP connections. It adds event IDs 3074 and 3075 to audit LDAP channel binding.

This lets admins check devices that don’t support or fail channel binding. It’s a step towards better channel binding, ad DS security, and ad LDS security in your network.

Improved Security for Confidential Attributes and Default Machine Account Passwords

The new DFL also boosts security for confidential attributes and machine account passwords. Now, domain controllers and AD LDS instances only allow encrypted LDAP operations for confidential attributes.

Also, Windows Server 2025 domain controllers prevent setting computer account passwords to the default name. This makes default machine account passwords more secure.

Feature	Windows Server 2022	Windows Server 2025
Channel Binding Audit	Not available	Supported with new event IDs 3074 and 3075
Confidential Attribute Security	Requires manual configuration	The default password can be set
Machine Account Password Security	Default password can be set	Default password setting blocked by domain controllers

These security updates in Windows Server 2025 DFL show Microsoft’s dedication to a safer ad DS security and ad LDS security environment for all organizations.

Kerberos and LDAP Protocol Advancements

Windows Server 2025 brings big changes to Kerberos and LDAP protocols. These updates help organizations meet new security needs and improve their ability to adapt to changing security standards. They make authentication and communication safer across the enterprise.

Kerberos PKINIT Support for Cryptographic Agility

The Windows Server 2025 updates the Kerberos PKINIT protocol. This change lets organizations use more algorithms and keep up with new security rules. It makes cryptographic agility better, helping organizations stay secure.

• Support for more algorithms in PKINIT
• Removal of fixed algorithms for more flexibility
• Boosts Kerberos and ad ds authentication security

LDAP Encryption by Default and TLS 1.3 Support

In Windows Server 2025, all ad lds ldap client communication is encrypted by default. This makes sure connections are secure. Also, LDAP now supports the latest tls 1.3 protocol, making security even better.

1. Secure ldap communication by default
2. Support for the latest tls 1.3 protocol
3. Improved security for ad ds ldap interactions

These updates in Kerberos and LDAP protocols help organizations stay ahead in security. They make authentication and communication safer and more secure.

Windows Server 2025 Domain Functional level

The Windows Server 2025 Domain Functional Level (DFL) brings new features to Active Directory. These updates are available for Windows Server 2016 and later versions. Upgrading can enhance your domain and forest functional levels.

Windows Server 2025 introduces a new Active Directory schema version, 89. This version adds new attributes for Managed Service Accounts (MSAs) and expands database settings. It makes managing and monitoring AD components easier.

The database page size for AD DS has grown from 8KB to 32KB. This allows for storing larger objects and multi-value attributes. Improvements in NUMA support and replication priority ordering also boost performance and scalability.

Feature	Description
32KB Database Page Size	Increased from 8KB, accommodating up to 3,200 values per object and reducing fragmentation.
NUMA Support	Optimized processor and memory utilization for large deployments, including virtualized environments.
Replication Priority Boost	Administrators can adjust the priority for specific replication partners, improving data synchronization efficiency.
Schema Version 89	Includes new attributes for Managed Service Accounts and expanded database settings.

The Windows Server 2025 DFL also includes security updates. These include better Kerberos support for the RC4 algorithm and TLS 1.3 support for LDAP over TLS. These changes help keep your Active Directory secure and robust.

In summary, the Windows Server 2025 Domain Functional Level offers many improvements. These can help organizations optimize their Active Directory environments and use the latest AD features.

Performance and Scalability Enhancements

Windows Server 2025 brings big improvements to Active Directory’s performance and scalability. It now uses Non-Uniform Memory Access (NUMA) hardware. This means Active Directory can use all CPU groups, not just the first 64 cores.

This change boosts the performance and scalability of Active Directory Domain Services (AD DS) and Active Directory Lightweight Directory Services (AD LDS).

The new replication priority order feature gives admins more control. They can now focus on replicating critical data first. This makes domain controller replication more efficient.

New Performance Counters for Monitoring and Troubleshooting

Windows Server 2025 also includes new performance counters. These counters help monitor and troubleshoot Active Directory features.

• DC Locator client and server-side counters
• LSA Name and SID lookup performance counters
• LDAP Client connection and request counters

These counters give admins a better view of their numa support, ad ds performance, and ad lds performance. They help spot and fix issues with replication priority, domain controller replication, and more.

Simplified Domain Controller Deployment

Windows Server 2025 makes it easier to set up domain controllers and other server roles. IT admins can now upgrade domain controllers through Windows Update. This is similar to how Windows 11 is updated.

For those who prefer a hands-on approach, Windows Server 2025 still allows manual installation. It also supports automated deployment using Sysprep. This gives admins the freedom to tailor the upgrade to their needs.

The new domain controller setup in Windows Server 2025 is a big improvement. It cuts down on the hassle and time of old upgrade methods. IT teams can now quickly deploy domain controller, AD DS, and AD LDS roles. This makes their Windows Server 2025 domain controller deployment more efficient.

Feature	Description
Windows Update Integration	Upgrade domain controllers directly through Windows Update, eliminating the need for installation media.
Manual Installation Flexibility	Retain the option to manually install Windows Server 2025 or use automated deployment methods based on Sysprep.
Streamlined Upgrade Process	Simplify the deployment of domain controllers and other Windows Server roles, reducing the complexity and time required for upgrades.

Azure Arc Integration

Microsoft’s Windows Server 2025 brings better integration with Azure Arc. This platform helps extend Azure services to various places, like data centers and edge locations. It also works with multi-cloud setups. This makes managing a hybrid cloud easier for IT admins.

The Azure Arc setup is now a default part of Windows Server 2025. This makes adding machines to Azure Arc simple. IT admins can use a built-in wizard and system tray icon. This helps them quickly add Windows Server 2025 machines to Azure Arc for better management.

This close link between Windows Server 2025 and Azure Arc helps manage ad ds hybrid and ad lds hybrid better. IT teams can use Azure Arc to manage their on-premises Windows Server 2025 easily. This ensures consistent management and visibility across all infrastructure.

Feature	Benefit
Seamless Azure Arc Integration	Streamlined onboarding and management of Windows Server 2025 machines in hybrid and multi-cloud environments
Centralized Monitoring and Control	Unified visibility and management of on-premises Windows Server 2025 deployments through Azure Arc
Consistent Governance and Policies	Extend Azure-based management and security controls to Windows Server 2025 machines in hybrid setups

By using the strong connection between Windows Server 2025 and Azure Arc, companies can get the most out of their hybrid cloud. They can extend Azure services to their on-premises setups. This leads to better efficiency, security, and flexibility in IT.

Compatibility and Functional Level Requirements

As organizations get ready to upgrade to Windows Server 2025, it’s key to know what’s needed. Your Active Directory must be at least Windows Server 2016 or later to use the new Windows Server 2025 Domain Functional Level.

This is important because the new Domain Functional Level adds to what came before. Upgrading to the new Domain and Forest Functional Levels is needed. This unlocks the latest features, security, and performance in Windows Server 2025.

Domain controllers also need to be ready for Windows Server 2025. This ensures a smooth transition to the new environment. Meeting these requirements lets businesses enjoy the latest advancements in Windows Server 2025.

Requirement	Details
ad ds functional level	Windows Server 2016 or later
ad lds functional level	Windows Server 2016 or later
windows server 2025 compatibility	Domain controllers must be compatible with the new release
domain controller compatibility	Domain controllers must be compatible with the new release

By making sure your Active Directory meets the requirements, you can fully benefit from Windows Server 2025. This prepares your organization for future success.

Upgrade Planning and Considerations

Upgrading to Windows Server 2025 Domain Functional Level needs careful planning. First, make sure your Active Directory is up to date. It should be running on Windows Server 2016 or later. Then, use PowerShell to raise the forest and domain levels to Windows Server 2025.

Finally, add Windows Server 2025 domain controllers. This will let you use the new features and capabilities.

Step-by-Step Guide to Upgrading to Windows Server 2025

1. Check if your Active Directory is on Windows Server 2016 or later.
2. Use PowerShell to set the forest and domain levels to Windows Server 2025:
   • Set-ADForestMode -Identity "contoso.com" -ForestMode "Windows2025Forest"
   • Set-ADDomainMode -Identity "contoso.com" -DomainMode "Windows2025Domain"
3. Install Windows Server 2025 domain controllers to use the new features.

Best Practices for a Smooth Transition

When upgrading to Windows Server 2025 Domain Functional Level, follow best practices. This ensures a smooth transition:

• Test the new features in a lab before using them in production.
• Tell key stakeholders and users about the upgrade plan and timeline.
• Have backup and disaster recovery plans ready for any upgrade issues.
• Watch the domain controllers and Active Directory performance during and after the upgrade.
• Train IT staff on the new features and management processes.

By following these best practices, organizations can have a successful upgrade. They will unlock better security, performance, and scalability features.

Conclusion

The Windows Server 2025 Domain Functional Level brings new features and improvements. These changes make Active Directory Domain Services (AD DS) and Active Directory Lightweight Domain Services (AD LDS) more secure, efficient, and easier to manage. Upgrading to this level lets organizations fully use their Active Directory, gaining better scalability, security, and easier setup of domain controllers.

This guide shows how to smoothly move to the Windows Server 2025 Domain Functional Level. It helps organizations get the most out of Active Directory. With features like a 32K database page size and hotpatching, Windows Server 2025 makes managing Active Directory easier and more efficient.

As Windows Server and Active Directory evolve, the Windows Server 2025 Domain Functional Level shows Microsoft’s dedication to innovation and success. By using these new features, businesses can stay ahead, using Active Directory to drive their digital transformation and tackle today’s IT challenges.

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