Within a cluster, it is recommended that all Brokers use SSL or no Brokers use SSL. Similarly, if encryption is enabled, it is enabled for all connections between Brokers in the cluster.

When the Broker Servers in a cluster are SSL-enabled, you can use an access control list (ACL) to identify which Brokers are authorized members of the cluster. Brokers that are not listed in the ACL, are not allowed to join or participate in the cluster.

For more information about securing a cluster, see Cluster ACLs.