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RADIUS is a protocol for remote user authentication (and authorization?) and accounting. Its primary use is for Internet Service Providers, though it may as well be used on any network that needs a centralized authentication and/or accounting service for its workstations.

RADIUS is often used in larger ["Wi-Fi"] (wireless) networks for authentication purposes, replacing the simple shared key methods which are uncomfortable if a Wi-Fi network reaches a specific size.

The ["DIAMETER"] protocol is the designated successor, but RADIUS is still commonly used today.


XXX - add a brief description of RADIUS history

Protocol dependencies

Example traffic

XXX - Add example traffic here (as plain text or Ethereal screenshot).


RADIUS dissector is fully functional.

Preference Settings

(XXX add links to preference settings affecting how RADIUS is dissected).

Example capture file

XXX - Add a simple example capture file. Keep it short, it's also a good idea to gzip it to make it even smaller, as Ethereal can open gzipped files automatically.

Display Filter

A complete list of RADIUS display filter fields can be found in the [ display filter reference]

Capture Filter

You cannot directly filter RADIUS protocols while capturing. However, if the RADIUS traffic is using one or more of the standard ["UDP"] ports (see above), you can filter on that port or ports.

RADIUS servers

See RadiusServers for information about various RADIUS server distributions.