Designing and Using Attributes

The standard RADIUS attributes are listed in the Attribute Definitions page.

When creating new RADIUS dictionaries or standards, you must follow the RADIUS Design Guidelines document (RFC 6158), and the Data Types in RADIUS document (RFC 8044).

Unfortunately, the RFCs are imperfect, and they have many issues and ambiguities. The Common Remote Authentication Dial In User Service (RADIUS) Implementation Issues and Suggested Fixes document (RFC 5080), resolves some of these discrepencies.

However, that document does not cover all the known issues with RADIUS. The RFCs are unclear in some areas, and does not always explicitly allowed or forbid behavior. Developers should not assume something is allowed just because it is not prohibited. Any new behavior that you invent is likely to conflict with After 20 years of RADIUS deployments. We recommend that you follow the RFC specifications closely for the best results. If you’re unsure about the RFCs, follow existing best practices, or ask on the freeradius-users mailing list.

Additional problems with the RADIUS standards and implementations are listed on the IETF RADEXT Wiki, and in the open issues page.