NPS Ports

Applies To: Windows Server 2008, Windows Server 2008 R2

By default, Network Policy Server (NPS) listens for Remote Authentication Dial-In User Service (RADIUS) traffic on the following User Datagram Protocol (UDP) ports.

RADIUS Traffic Type

UDP Port

Authentication traffic


Accounting traffic


Authentication traffic


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 do not use the RADIUS default port numbers, you must configure exceptions on the firewall of the local computer to allow RADIUS traffic on the new ports.

Connecting to a remote SQL server

When you configure NPS to log accounting information to a database on a remote SQL Server, you must also create a firewall exception on the SQL Server to allow the incoming connection from the NPS server. By default, SQL Server listens for incoming connections on TCP port 1433. For more information, see INF: TCP Ports Needed for Communication to SQL Server Through a Firewall.