An immutable system is a system that does not change after it is deployed. Any changes or updates are done by creating a new system from a common image or template and replacing the old one. An immutable system meets the requirements of storing data outside of the VMs, preventing unauthorized modifications to the VMs, and deploying a new VM if a change needs to be done. An immutable system can improve the security, reliability, and consistency of the VMs by avoiding configuration drift, human errors, or malicious tampering. An immutable system can also simplify the deployment process and enable faster recovery from failures. Verified Reference:
https://cloudinfrastructureservices.co.uk/vm-types-for-devops-pets-vs-cattle-vs-immutable/
https://www.digitalocean.com/community/tutorials/what-is-immutable-infrastructure

A screened subnet is a network segment that separates two different environments, such as ## (operational technology) and IT (information technology), and provides security controls to limit and monitor the traffic between them. This would allow the business to get the required reports from the historian server without exposing the ## environment to unnecessary risks. Using a VPN, allowing IT traffic, or allowing PLCs to send data are less secure options that could compromise the ## environment. Verified References:
https://www.comptia.org/blog/what-is-operational-technology https://partners.comptia.org/docs/default-source
/resources/casp-content-guide

Wireless network auto joining is the mobile configuration setting that the mobile administrator is verifying by reviewing the mobile device DHCP logs. Wireless network auto joining is a feature that allows mobile devices to automatically connect to a predefined wireless network without requiring user intervention or authentication. This can be useful for corporate or trusted networks that need frequent access by mobile devices. The DHCP logs show that the mobile devices are assigned IP addresses from the wireless network with SSID "CorpWiFi", which indicates that they are auto joining this network.