. Configure Transport Layer Security (TLS/SSL).
+
--
If have enabled {security}, you must configure TLS for internode-communication.

NOTE: This requirement applies to clusters with more than one node and to
clusters with a single node that listens on an external interface. Single-node
clusters that use a loopback interface do not have this requirement.  For more
information, see
{xpack-ref}/encrypting-communications.html[Encrypting Communications].

--
.. <<node-certificates,Generate node certificates for each of your {es} nodes>>.

.. <<tls-transport, Enable TLS on each {es} node>>.