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Configure NPS UDP Port Information

Applies To: Windows Server 2008

Configure NPS UDP port information

You can use the following procedure to configure the ports that Network Policy Server (NPS) uses for RADIUS authentication and accounting traffic.

By default, NPS listens for RADIUS traffic on ports 1812, 1813, 1645, and 1646 for both Internet Protocol version 6 (IPv6) and IPv4 for all installed network adapters.


If you uninstall either IPv4 or IPv6 on a network adapter, NPS does not monitor RADIUS traffic for the uninstalled protocol.

The values of 1812 for authentication and 1813 for accounting are RADIUS standard ports defined in RFCs 2865 and 2866. However, by default, many access servers use ports 1645 for authentication requests and 1646 for accounting requests. No matter which port numbers you decide to use, make sure that NPS and your access server are configured to use the same ones.


If you do not use the RADIUS default port numbers, you must configure exceptions on the firewall for the local computer to allow RADIUS traffic on the new ports. For more information, see NPS and Firewalls.

Membership in Domain Admins, or equivalent, is the minimum required to complete this procedure.

To configure NPS UDP port information using the Windows interface

  1. Open the NPS console.

  2. Right-click Network Policy Server, and then click Properties.

  3. Click the Ports tab, and then examine the settings for ports. If your RADIUS authentication and RADIUS accounting UDP ports vary from the default values provided (1812 and 1645 for authentication, and 1813 and 1646 for accounting), type your port settings in Authentication and Accounting.

  4. To use multiple port settings for authentication or accounting requests, separate the port numbers with commas.

See Also


Configure NPS on a Multihomed Computer