FreeRADIUS is an Internet authentication daemon, which implements the RADIUS
protocol, as defined in RFC 2865 (and others). It allows Network Access
Servers (NAS boxes) to perform authentication for dial-up users. There are
also RADIUS clients available for Web servers, firewalls, Unix logins, and
more. Using RADIUS allows authentication and authorization for a network to
be centralized, and minimizes the amount of re-configuration which has to be
done when adding or deleting new users.