External authentication of RAPs does not work in Cluster Setup
Why does the external authentication for RAP's does not work in a Cluster Setup?
Addition of RAP's MAC in whitelistDB triggers the allocation of inner IP address for the respective entries beforehand from L2TP pool. When it comes to Clustering with external WhitelistDB(ClearPass or any Radius servers), pre-allocation of inner IP from L2TP pool does not happen. Hence RAP fails from getting an inner IP from L2TP pool. Therefore it is always recommended to use Internal-db for RAP whitelist in Clustering setup.