The RADIUS client uses a source port (UDP listener) for negotiating access requests with the RADIUS server. This port allows the simultaneous negotiation of up to 256 IDs. If a client is processing a large number of requests at the same time and the RADIUS server is far away, it is possible for all 256 access requests to be open at the same time, causing the RADIUS client to be unable to handle any further requests. This can happen, for example, in extensive Eduroam environments.
In this case, the RADIUS client opens the next highest source port to enable the access request negotiation for additional IDs. This is automatic and is not configurable.
