Registered · Cross-platform

1645 RADIUS (legacy auth)

TCP No
UDP Unofficial
SCTP
DCCP

What it is

Pre-standard RADIUS authentication port.

When / why

Legacy Cisco/RADIUS deployments; modern uses 1812.

Protocol status detail

TransportStatusMeaning
TCP No Not assigned, standardized, or widely used on this port.
UDP Unofficial Not assigned by IANA, but standardized, specified, or widely used on this port.
SCTP Not applicable for this transport.
DCCP Not applicable for this transport.

Port range

Registered (1024–49151). Assigned by IANA on request; usable without elevated privileges on most systems.

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