Windows Server 2025: Administration Fundamentals

Introduction to Windows Server 2025: What's New?

New Features and Enhancements

Windows Server 2025 adds capabilities that streamline administration and hardening. Notable improvements include tighter Secured-core server controls, enhanced container support for both Windows and Linux containers, improved SMB compression for faster file transfers, and deeper hybrid management integration with Azure tooling for on-premises resources.

The Windows Admin Center + Azure Arc hybrid management model now enables single-pane operations for inventory, update management, and extension deployment. For a concrete scenario: onboard an on-premises server to Azure Arc to enable centralized policy and monitoring — install the Connected Machine agent on the server, register it to a target Azure resource group, then apply Azure Policy to enable update management and an Azure Monitor agent to collect performance counters and event logs. In practice this lets you see inventory, install extensions (for example, a backup or monitoring agent), and enforce configuration baselines from a cloud control plane while the server remains on-premises.

Performance features like SMB compression benefit large file migrations and backups; on high-latency links SMB compression can substantially reduce transfer time for large datasets.

• Integration with Azure Arc and hybrid tooling
• Improved container support (Windows and Linux containers)
• Secured-core server features and hardware attestation
• SMB compression for faster file transfers

Quick check: Secured-core and platform security

Before enabling Secured-core features in production, validate platform capabilities (Secure Boot, TPM 2.0, and related virtualization-based protections). Use these simple PowerShell checks (works from an elevated session; PowerShell 7.2 can invoke these commands):

# Check Secure Boot status
Get-CimInstance -ClassName Win32_ComputerSystem -Namespace root\cimv2 | Select-Object SecureBootEnabled

# Check TPM presence and readiness (requires the TPM module in Windows PowerShell/pwsh)
Get-Tpm | Select-Object TpmPresent, TpmReady, ManufacturerId, ManufacturerVersion

Security insights and troubleshooting tips:

• If SecureBootEnabled returns False, enable Secure Boot in the system UEFI (requires reboot and vendor firmware settings). Document firmware changes and test in a lab before rolling out.
• If Get-Tpm reports TPM not present or not ready, verify platform firmware settings (TPM enabled and ownership cleared) and ensure the host is running UEFI (not legacy BIOS).
• When enabling virtualization-based security (HVCI / Credential Guard), test application compatibility (drivers and security agents) on a representative subset of servers to avoid unexpected reboots or driver failures.
• Log these checks and include them in your build pipeline (for example, run as part of image validation in your CI pipeline or build scripts executed by PowerShell 7.2 orchestration).

Setting Up Your Windows Server 2025 Environment

Installation and Configuration Steps

Start by obtaining the ISO or installation media from the vendor site (for general downloads and licensing, visit the vendor's main site such as Microsoft). Choose between a clean installation and an in-place upgrade based on your migration plan. In lab work I recommend a clean install to validate roles and features without impacting production.

After the OS is installed, add roles and features using Server Manager or PowerShell. For Active Directory Domain Services (AD DS):

Install-WindowsFeature -Name AD-Domain-Services -IncludeManagementTools

Follow with Install-ADDSForest (for the first DC) or use scripted deployments. Always run these as an elevated administrator. For automation, build repeatable scripts using PowerShell 7.2 and document prerequisites (disk layout, NIC naming, time configuration). In mixed environments, test compatibility of ServerManager cmdlets and plan for the approach described in PowerShell Compatibility Notes.

PowerShell Compatibility Notes

Background: Some Windows Server role and feature cmdlets (for example, Get-WindowsFeature and Install-WindowsFeature) are implemented in the ServerManager module that runs under Windows PowerShell (5.1). PowerShell 7.2 (pwsh) is the recommended cross-platform shell for modern automation, but a handful of legacy server-management cmdlets remain tied to the Windows PowerShell runtime. To avoid duplication and confusion, manage compatibility centrally.

Recommended approaches

• Run legacy ServerManager cmdlets in an elevated Windows PowerShell (powershell.exe) session when interactive tasks are required.
• From PowerShell 7.2 scripts, invoke Windows PowerShell for specific commands and capture structured output to continue processing in pwsh.
• Automate hybrid workflows by separating concerns: use pwsh for orchestration (logic, parsing, API calls) and call powershell.exe for ServerManager-specific operations.

Practical examples

1) Check Data Deduplication status and install it when needed — from PowerShell 7.2 call Windows PowerShell and parse JSON output:

# From PowerShell 7.2 (pwsh), invoke Windows PowerShell for ServerManager cmdlets
$pwshPath = "C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\powershell.exe"
$command = "Get-WindowsFeature -Name 'FS-Data-Deduplication' | Select-Object Name,InstallState | ConvertTo-Json -Compress"
$raw = & $pwshPath -NoProfile -WindowStyle Hidden -Command $command
if (-not $raw) { throw 'Failed to query Windows PowerShell for Get-WindowsFeature' }
$feature = $raw | ConvertFrom-Json
if ($feature.InstallState -ne 'Installed') {
    Write-Host "FS-Data-Deduplication is not installed. Installing..."
    & $pwshPath -NoProfile -Command "Install-WindowsFeature -Name FS-Data-Deduplication -IncludeManagementTools"
} else {
    Write-Host "FS-Data-Deduplication is already installed."
}

2) Alternative: call an elevated Windows PowerShell process from automation platforms (Azure DevOps, Jenkins, or a scheduled task) to run ServerManager-specific scripts and return JSON for pwsh parsing. This lets you keep orchestration logic in pwsh while using the Windows PowerShell runtime only when required.

Operational tips

• Always run ServerManager cmdlets elevated (Administrator) to avoid permission failures.
• Log raw command output and errors from the invoked powershell.exe call for troubleshooting.
• Where possible, prefer built-in REST APIs, DSC resources, or vendor APIs that are native to pwsh to reduce cross-runtime calls.

User and Group Management: Best Practices

Effective User Management Strategies

Implement the principle of least privilege and use role-based access control (RBAC). Map job roles to AD groups and apply Group Policy Objects (GPOs) at OU level to enforce baseline security settings. Schedule quarterly permission reviews and automate reporting for stale accounts.

Example PowerShell to list users and enabled status (requires ActiveDirectory module):

Get-ADUser -Filter * -Properties Enabled | Select-Object Name, Enabled

Tip: run this from a management workstation with RSAT or on a domain-joined server with the AD PowerShell module installed. Export results to CSV for audit workflows: ... | Export-Csv -Path C:\Temp\ADUsers.csv -NoTypeInformation.

Networking Fundamentals in Windows Server 2025

Understanding Networking Features

Core services like DHCP and DNS remain foundational. Use DHCP to centralize IP management and reduce conflicts; DNS for hostname resolution and service discovery. For remote access, RRAS or modern VPN solutions provide encrypted connectivity—plan capacity and encryption (for example, AES-256) based on user counts and throughput.

Quality of Service (QoS): Policy-based QoS helps ensure critical traffic (VoIP, conferencing, replication) receives priority. In Windows Server you can configure QoS via Group Policy (Policy-based QoS) or use the NetQos PowerShell cmdlets. Example: assign DSCP 46 to a VoIP application to prioritize RTP packets.

# Example: create a QoS policy that sets DSCP for a specific app path (run in elevated PowerShell)
New-NetQosPolicy -Name "VoIP-App-QoS" -AppPathNameMatchCondition "C:\\Program Files\\VoIP\\voip.exe" -IPProtocolMatchCondition UDP -DSCPAction 46

Monitor QoS counters and validate traffic marking on edge devices. When integrating with network equipment, coordinate DSCP policies across switches and routers to preserve markings end-to-end.

• Automated IP address management with DHCP
• Hostname resolution using DNS
• Secure remote access via VPN/RRAS
• Bandwidth management with Policy-based QoS (DSCP marking)

Security Features and Compliance in Windows Server 2025

Enhancing Security Posture

Windows Server 2025 supports Secured-core server features, hardware attestation, and integration with Microsoft Defender for Endpoint for endpoint detection and response. Deploying Defender for Endpoint across servers gives centralized alerts and remediation actions; integrate alerts into your SIEM for extended visibility.

Disk encryption with BitLocker should be standard for servers that host sensitive data. Example to enable BitLocker on C: using AES-256:

Enable-BitLocker -MountPoint 'C:' -EncryptionMethod Aes256 -UsedSpaceOnlyEncryption

Security best practices: enable secure boot, keep firmware updated, enforce MFA for admin accounts, and use Just-In-Time (JIT) or Just-Enough-Administration (JEA) where possible to reduce standing privileges.

• Endpoint detection with Microsoft Defender for Endpoint
• Disk encryption via BitLocker
• Regular audits for compliance and configuration drift
• Reduce admin exposure with AD and Privileged Access Management

Lessons learned

From real operations: when a ransomware outbreak impacted a customer’s file servers, the combination of isolated VLAN segments, offline backups, and a tested restore playbook limited impact and reduced downtime. The key takeaways: (1) test restores regularly, (2) limit lateral movement via network segmentation and least privilege, and (3) maintain immutable or offline backups that are not continuously writable from production systems.

Troubleshooting and Maintenance for Optimal Performance

Identifying Common Issues

Use built-in tools (Performance Monitor, Resource Monitor, Event Viewer) to identify memory, CPU, and disk bottlenecks. Example: to list top CPU-consuming processes:

Get-Process | Sort-Object -Property CPU -Descending | Select-Object -First 10

For disk issues, use chkdsk and assess storage subsystem performance with PerfMon counters (Disk Queue Length, Avg. Disk sec/Read). For reproducible problems, capture ETW traces or use Windows Performance Recorder (WPR) and Windows Performance Analyzer (WPA) for deep analysis.

Regular Maintenance Practices

Schedule updates during maintenance windows and automate patching with an update management solution (for example, WSUS or cloud update management). Backups are critical — use built-in tools or third-party solutions that support application-consistent backups for SQL, Exchange, and other stateful services.

To perform a basic full backup with the built-in wbadmin tool (run elevated from an administrative command prompt):

wbadmin start backup -backupTarget:D:\Backups -include:C: -quiet

wbadmin runs outside PowerShell in an elevated shell and requires the Windows Server Backup feature installed. For larger environments use enterprise backup platforms or cloud backup (for example, Azure Backup) for cloud-integrated recovery.

• Monitor memory and CPU usage weekly
• Schedule backups nightly (or according to RPO/RTO)
• Review and archive event logs on a regular cadence
• Validate restores periodically (test your backups)

Key Concepts (Glossary)

Secured-core server

Hardware-rooted security features (firmware protection, virtualization-based security) to reduce firmware- and boot-level attacks.

Azure Arc

Hybrid management approach that lets you manage on-premises servers and cloud resources from a central control plane.

SMB compression

Feature to compress file data during SMB transfers to reduce network transfer time for large files.

AD DS

Active Directory Domain Services — centralized identity and access management for Windows environments.

Policy-based QoS / DSCP

Mechanism to mark and prioritize network traffic; DSCP values are preserved across network devices to ensure class-based treatment.

PowerShell 7.2

Cross-platform PowerShell release used for automation. Some Windows roles/features still require Windows PowerShell (5.1) runtime — see PowerShell Compatibility Notes.