RADIUS

	Port	Encryption	Use Case
RADIUS	UDP 1812/1813	Encrypt passwords only	Network access control

Extensions

Extension	Port	Introduction
Change of Authorization (CoA)	UDP 1700	Allow dynamically modify an active user or device's session permissions (e.g., VLAN, bandwidth, access level) in real-time without requiring re-authentication.

Application of RADIUS

Feature	Windows (NPS)	Linux (FreeRADIUS)
Platform	Windows Server only	Most Linux distributions
GUI	Yes	No (CLI + config files)
AD Integration	Native	Possible (requires setup)
Customizability	Limited	Very high
Resource Usage	Moderate to high	Lightweight
Licensing	Requires Windows Server license	Free (open-source)
Use Case Fit	Enterprise with AD	ISP, universities, cloud, etc.

Configuration Example