By default, don't sniff other data nodes in the cluster, and use the addresses provided as is (important when working outside of the cloud, using the public address).

Add client.transport.sniff which can be set to true to enable sniffing and using all data nodes in the cluster. This is how it can be set:

TransportClient client = new TransportClient(settingsBuilder().put("client.transport.sniff", true).build());