NPS (Network Policy Server)

Introduction

In today’s lesson from the MCSA Full Course, we’ll explore Network Policy Server (NPS) in detail. NPS is Microsoft’s implementation of a RADIUS (Remote Authentication Dial-In User Service) server, used to centralize authentication, authorization, and accounting for network access.

It is a critical component in enterprise environments where administrators need to manage secure access to VPNs, wireless connections, and other network resources.

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What is NPS?

NPS (Network Policy Server) is a role in Windows Server that allows administrators to define and enforce network access policies.

It provides:

• Authentication → Verifies the identity of users and devices.
• Authorization → Determines what level of access the user/device should have.
• Accounting → Tracks session duration, data usage, and other logging details.

NPS integrates with Active Directory and supports multiple authentication methods such as:

• Username & Password
• Digital Certificates
• Smart Cards

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Why Do We Use NPS?

NPS is widely used because it:

• Ensures secure access control for VPN and wireless users.
• Centralizes policy management for consistent enforcement across the network.
• Provides detailed accounting logs for compliance and monitoring.
• Supports integration with a wide range of devices (routers, switches, firewalls) that use the RADIUS protocol.

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Key Functions of NPS (AAA)

🔑 Authentication

• Verifies the identity of users or devices before granting access.
• Supports password-based, certificate-based, and smart card authentication.

🔑 Authorization

• After authentication, NPS checks what resources the user/device can access.
• Policies can be based on:
  • User or group membership
  • Network location
  • Time of day
  • Device type

🔑 Accounting

• Tracks session duration, data usage, and connection status.
• Helps administrators monitor activity and maintain audit logs.

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Practical Example with VPN

Imagine a company where employees connect through VPN:

• Without NPS → Any authenticated user can connect freely, without strict policies.
• With NPS →
  • Only members of a specific VPN Users group can connect.
  • Policies define allowed times, encryption strength, and session duration.
  • Logging ensures visibility of who connected and for how long.

This ensures strong security and controlled access to company resources.

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Real-World Use Cases of NPS

• Corporate VPN Access: Restrict connections only to approved users.
• Wireless Authentication: Secure Wi-Fi in enterprises and universities.
• Time-based Access Control: Allow connections only during working hours.
• Multi-server Environments: Use RADIUS with multiple VPN servers for scalability.
• Hotels & Universities: Temporary Wi-Fi access with auto-expiry.

NPS Interview Questions and Answers