Microsoft has released Windows Server 2025 Insider Preview Build 26311, offering IT professionals and developers an early look at the next generation of server technology. This build introduces several groundbreaking features and security enhancements that promise to redefine enterprise computing.

What's New in Build 26311

The latest Insider Preview brings significant improvements across multiple areas:

  • Enhanced Windows Defender Application Control (WDAC): Now with improved policy management and deployment options
  • Storage Migration Service updates: Simplified large-scale storage migrations with new automation capabilities
  • Active Directory improvements: Faster replication and enhanced security auditing
  • Container optimizations: Better performance for Kubernetes workloads and Windows containers

Security Enhancements

Security remains a top priority in Windows Server 2025, with Build 26311 introducing:

1. Advanced WDAC Capabilities

Microsoft has expanded WDAC with:
- Simplified policy creation through new PowerShell cmdlets
- Enhanced logging for better troubleshooting
- Support for more granular application control scenarios

2. Secure Core Server Improvements

  • Hardware-enforced security measures
  • TPM 2.0 integration enhancements
  • Secure boot optimizations

3. Network Protection

  • New DNS over HTTPS (DoH) support
  • Enhanced SMB encryption options
  • Improved firewall logging

Performance Optimizations

Build 26311 shows measurable improvements in:

  • Virtualization: Up to 15% better performance for nested virtualization scenarios
  • Storage: NVMe optimizations deliver lower latency
  • Networking: Reduced CPU overhead for high-speed network adapters

Deployment and Management

The preview includes several tools to simplify server management:

  • New Windows Admin Center extensions
  • Enhanced Azure Arc integration
  • Improved DSC (Desired State Configuration) capabilities

Known Issues

Microsoft has identified several areas still under development:

  • Some Storage Replica scenarios may fail
  • Certain Hyper-V features remain unstable
  • Limited driver support for newer hardware

How to Get the Preview

IT professionals can access Build 26311 through:

  1. Windows Server Insider Program
  2. Azure Marketplace images
  3. ISO downloads from Microsoft's Insider site

Providing Feedback

Microsoft encourages users to report issues through:

  • The Feedback Hub app
  • Server-specific feedback channels
  • Microsoft's Tech Community forums

Looking Ahead

This build represents a significant step toward the final release of Windows Server 2025, expected in late 2024. The focus on security and hybrid cloud integration positions this as a crucial upgrade for modern enterprises.