RADIUS attribute from rfc3576


Error-Cause

It is possible that the NAS cannot honor Disconnect-Request or
      CoA-Request messages for some reason.  The Error-Cause Attribute
      provides more detail on the cause of the problem.  It MAY be
      included within Disconnect-ACK, Disconnect-NAK and CoA-NAK
      messages.

      A summary of the Error-Cause Attribute format is shown below.  The
      fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |             Value
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      101 for Error-Cause

   Length

      6

   Value

      The Value field is four octets, containing an integer specifying
      the cause of the error.  Values 0-199 and 300-399 are reserved.
      Values 200-299 represent successful completion, so that these
      values may only be sent within Disconnect-ACK or CoA-ACK message
      and MUST NOT be sent within a Disconnect-NAK or CoA-NAK.  Values400-499 represent fatal errors committed by the RADIUS server, so
      that they MAY be sent within CoA-NAK or Disconnect-NAK messages,
      and MUST NOT be sent within CoA-ACK or Disconnect-ACK messages.
      Values 500-599 represent fatal errors occurring on a NAS or RADIUS
      proxy, so that they MAY be sent within CoA-NAK and Disconnect-NAK
      messages, and MUST NOT be sent within CoA-ACK or Disconnect-ACK
      messages.  Error-Cause values SHOULD be logged by the RADIUS
      server.  Error-Code values (expressed in decimal) include:

    #     Value
   ---    -----
   201    Residual Session Context Removed
   202    Invalid EAP Packet (Ignored)
   401    Unsupported Attribute
   402    Missing Attribute
   403    NAS Identification Mismatch
   404    Invalid Request
   405    Unsupported Service
   406    Unsupported Extension
   501    Administratively Prohibited
   502    Request Not Routable (Proxy)
   503    Session Context Not Found
   504    Session Context Not Removable
   505    Other Proxy Processing Error
   506    Resources Unavailable
   507    Request Initiated

   "Residual Session Context Removed" is sent in response to a
   Disconnect-Request if the user session is no longer active, but
   residual session context was found and successfully removed.  This
   value is only sent within a Disconnect-ACK and MUST NOT be sent
   within a CoA-ACK, Disconnect-NAK or CoA-NAK.

   "Invalid EAP Packet (Ignored)" is a non-fatal error that MUST NOT be
   sent by implementations of this specification.

   "Unsupported Attribute" is a fatal error sent if a Request contains
   an attribute (such as a Vendor-Specific or EAP-Message Attribute)
   that is not supported.

   "Missing Attribute" is a fatal error sent if critical attributes
   (such as NAS or session identification attributes) are missing from a
   Request.

   "NAS Identification Mismatch" is a fatal error sent if one or more
   NAS identification attributes (see.) do not match the
   identity of the NAS receiving the Request."Invalid Request" is a fatal error sent if some other aspect of the
   Request is invalid, such as if one or more attributes (such as EAP-
   Message Attribute(s)) are not formatted properly.

   "Unsupported Service" is a fatal error sent if a Service-Type
   Attribute included with the Request is sent with an invalid or
   unsupported value.

   "Unsupported Extension" is a fatal error sent due to lack of support
   for an extension such as Disconnect and/or CoA messages.  This will
   typically be sent by a proxy receiving an ICMP port unreachable
   message after attempting to forward a Request to the NAS.

   "Administratively Prohibited" is a fatal error sent if the NAS is
   configured to prohibit honoring of Request messages for the specified
   session.

   "Request Not Routable" is a fatal error which MAY be sent by a RADIUS
   proxy and MUST NOT be sent by a NAS.  It indicates that the RADIUS
   proxy was unable to determine how to route the Request to the NAS.
   For example, this can occur if the required entries are not present
   in the proxy's realm routing table.

   "Session Context Not Found" is a fatal error sent if the session
   context identified in the Request does not exist on the NAS.

   "Session Context Not Removable" is a fatal error sent in response to
   a Disconnect-Request if the NAS was able to locate the session
   context, but could not remove it for some reason.  It MUST NOT be
   sent within a CoA-ACK, CoA-NAK or Disconnect-ACK, only within a
   Disconnect-NAK.

   "Other Proxy Processing Error" is a fatal error sent in response to a
   Request that could not be processed by a proxy, for reasons other
   than routing.

   "Resources Unavailable" is a fatal error sent when a Request could
   not be honored due to lack of available NAS resources (memory, non-
   volatile storage, etc.).

   "Request Initiated" is a fatal error sent in response to a Request
   including a Service-Type Attribute with a value of "Authorize Only".
   It indicates that the Disconnect-Request or CoA-Request has not been
   honored, but that a RADIUS Access-Request including a Service-Type
   Attribute with value "Authorize Only" is being sent to the RADIUS
   server.
        FreeRADIUS Vendor-Specific dictionary values:
201 - Residual-Context-Removed 202 - Invalid-EAP-Packet 401 - Unsupported-Attribute 402 - Missing-Attribute 403 - NAS-Identification-Mismatch 404 - Invalid-Request 405 - Unsupported-Service 406 - Unsupported-Extension 501 - Administratively-Prohibited 502 - Proxy-Request-Not-Routable 503 - Session-Context-Not-Found 504 - Session-Context-Not-Removable 505 - Proxy-Processing-Error 506 - Resources-Unavailable 507 - Request-Initiated 407 - Invalid-Attribute-Value 508 - Multiple-Session-Selection-Unsupported 601 - Response-Too-Big