The blog post by Kuniyasu Sen provides a detailed guide on setting up TLS for Elasticsearch, Kibana, Logstash, and Filebeat on a two-node cluster using an offline installation on CentOS 7. It addresses how to perform this setup using RPM packages for environments where direct internet access is unavailable, emphasizing the importance of securing communication within the Elastic Stack. The process involves installing Elasticsearch and its X-Pack plugin, creating SSL certificates, enabling TLS, and configuring each component for secure data transport. The guide is aimed at demonstrating a sandbox setup and advises further adjustments for production environments, such as using a minimum of three nodes for high availability and commercially signed certificates. Despite the guide being based on older Elastic Stack versions 6.2.3, it serves as a foundational reference for setting up secure, offline installations, with a note that it uses deprecated features and links to more current documentation for Elastic Stack 6.8/7.1 or later.