Loading...
RADIUS Authentication (Cisco/Juniper)
Port 1645 was traditionally used for RADIUS authentication messages by vendors like Cisco and Juniper. As a protocol, RADIUS (Remote Authentication Dial In User Service) facilitates centralized Authentication, Authorization, and Accounting (AAA) for accessing network resources, widely adopted in network access servers, wireless controllers, VPNs, and more. Despite newer official port allocations, port 1645 remains in use in certain legacy or vendor-specific deployments..
RADIUS (Remote Authentication Dial-In User Service) is a protocol designed to manage user authentication, authorization, and accounting, primarily in dial-up services but now used extensively across various network access scenarios like Wi-Fi, VPNs, and corporate networks. Port 1645 was historically used by Cisco and Juniper RADIUS authentication servers before IANA officially assigned ports 1812 (authentication) and 1813 (accounting).
RADIUS operates using a client-server model, where the NAS (Network Access Server) acts as a client and forwards user credentials to the RADIUS server for validation. Communication can occur over UDP and sometimes TCP, though UDP remains the primary transport. The packets include attribute-value pairs that facilitate user policy enforcement and session control.
While newer implementations favor the official ports, port 1645 is still in use because of legacy configurations and older equipment. The protocol supports multiple authentication methods, including PAP, CHAP, and EAP, and is designed for extensibility through vendor-specific attributes.