Remote Authentication Dial-In User Service (RADIUS) is a networking protocol that provides centralized Authentication, Authorization, and Accounting (AAA) management for users who connect and use a network service. RADIUS is widely used in various environments to manage network access, especially in enterprise settings. In the Windows environment, RADIUS can be implemented using the Network Policy Server (NPS) role on Windows Server. This article will guide you through the process of setting up RADIUS on a Windows Server.

Examples:

1. Install the Network Policy Server (NPS) Role:

   To set up RADIUS on Windows Server, you first need to install the NPS role. This can be done via the Server Manager or using PowerShell.

   Using Server Manager:

   • Open Server Manager.
   • Click on "Manage" and select "Add Roles and Features."
   • In the "Add Roles and Features Wizard," select "Role-based or feature-based installation" and click "Next."
   • Select the server you want to install the role on and click "Next."
   • In the "Select server roles" section, check "Network Policy and Access Services" and click "Next."
   • Proceed through the wizard and click "Install."

   Using PowerShell:

   Install-WindowsFeature NPAS -IncludeManagementTools

2. Configure NPS as a RADIUS Server:

   After installing the NPS role, you need to configure it as a RADIUS server.

   • Open the NPS console by typing nps.msc in the Run dialog (Win + R).
   • In the NPS console, right-click on "NPS (Local)" and select "Register server in Active Directory."
   • Confirm the registration by clicking "OK."
   • Right-click on "RADIUS Clients" and select "New."
   • Enter a friendly name and the IP address of the RADIUS client (e.g., a wireless access point or VPN server).
   • Set a shared secret, which will be used for communication between the RADIUS server and client.
   • Click "OK" to add the RADIUS client.

3. Create Network Policies:

   Network policies define who can connect to the network and the conditions for connection.

   • In the NPS console, expand "Policies" and right-click on "Network Policies."
   • Select "New" to create a new policy.
   • Provide a policy name and specify the conditions under which the policy applies (e.g., user groups, day and time restrictions).
   • Configure the authentication methods, such as PEAP or MS-CHAPv2.
   • Define any constraints and settings, such as idle timeouts or encryption settings.
   • Click "Finish" to create the policy.

4. Test the RADIUS Configuration:

   Ensure that the RADIUS server is correctly configured by testing the connection from a RADIUS client.

   • Use a RADIUS client, such as a wireless access point or VPN server, to attempt a connection.
   • Monitor the NPS console for events and logs to verify successful authentication.

By following these steps, you can configure a RADIUS server on a Windows Server to manage network access and authentication.