Symptom

- CAPWAP data tunnel is not established between 9800-CL catalyst and OEAP. AP Running Image : 17.9.1.201 WLC image : 17.9.1 WLC model: 9800-CL 6 APs model C9105AXW-E , 1 AP model C9120AXI-E ( both of them showing same behavior ) -Issue on establishing a new data DTLS connection after changing the public IP from the ISP

Conditions

- At the time of the issue we can see that AP showing Data CAPWAP as NULL: DTLSv1.2 TLS_NUM_RSA_WITH_AES_128_CBC_SHA >>>> Control CAPWAP Capwap_Data 0 UNKNOWN TLS_NUM_NULL_WITH_NULL_NULL >>>> Data CAPWAP - AP debugs there is issue on establishing a new data DTLS connection after changing the public IP from the ISP and noticed there is existence connection per the AP logs for the data tunnel: dtls_new_connection: Connection 0x20c9400 is already there for this server port 5247, Deleting it. Number of connections: 2 wtpDtlsCallback: Data DTLS Connection was there, tearing down connection. dtls_disconnect: ERROR shutting down dtls connection ...

Workaround

Disable Link Encryption

Further Problem Description