RADIUS - UDP Port Numbers

UDP Port Numbers

RADIUS has been officially assigned UDP ports 1812 for RADIUS Authentication and 1813 for RADIUS Accounting by the Internet Assigned Numbers Authority (IANA). However, prior to IANA allocation of ports 1812 and 1813, ports 1645 and 1646 (authentication and accounting, respectively) were used unofficially and became the default ports assigned by many RADIUS Client/Server implementations of the time. The tradition of using 1645 and 1646 for backwards compatibility continues to this day. For this reason many RADIUS Server implementations monitor both sets of UDP ports for RADIUS requests. Microsoft RADIUS servers default to 1812 and 1813. Cisco RADIUS servers listen on RADIUS ports UDP 1645 and UDP 1812 for authentication; on ports 1646 and 1813 for accounting and can be configured with non-standard ports. Juniper Networks' RADIUS servers listen on both unofficial and official ports 1645, 1812, 1646 and 1813 by default but can be configured with arbitrary ports.SBR. Cloudessa and Avaya virtual RADIUS solutions assign a pair of unique authentication and accounting ports to each virtual RADIUS server.