CI Fortify is a guidance term used in critical-infrastructure security to describe hardening vital systems so they can be isolated without losing the ability to operate, monitor, and recover. In practice, it is less about a specific tool and more about a resilience plan: identifying which connections must remain available, which can be removed, and how operators will coordinate during a disruption.
This matters because industrial environments such as utilities, plants, and transport systems cannot always be disconnected cleanly. During attacks, segmentation or emergency isolation may stop malware spread, but it can also cut off legitimate control and response channels. CI Fortify reflects the defensive idea that secure separation must be designed in advance, tested, and paired with communications continuity. That makes it relevant to OT incident response, recovery planning, and the protection of services that must stay safe under pressure.