Typically port 9042 is provided with the Cassandra cluster seed hosts to connect to Cassandra cluster for performing CRUD operations.
Does Cassandra Java client driver has knowledge of port 7000 (used for peer communication) after the client establishes connection with Cassandra cluster?
Thanks, Deepak
The Java driver doesn't make use of the internode communication port 7000 because it doesn't need to participate in gossip with the nodes in the cluster.
Instead, the Java driver establishes a control connection with one of the nodes the first time it connects to the cluster. The driver uses the control connection (1) to query the system tables to discover the cluster's topology and schema, and (2) listen to topology and schema changes.
It is in point (2) above that the driver recognises when nodes are added or decommissioned from the cluster as well as find out when the schema has been updated. This is the reason the driver doesn't need to gossip with the nodes.
For more information, see Control connection for the Java driver. Cheers!