Zero Trust Microsegmentation Guidance

Microsegmentation is a foundational Zero Trust strategy that strengthens security by enforcing explicit, fine-grained communication controls between systems, reducing attack paths, and limiting lateral movement. This paper explores the evolving role of microsegmentation as a practical enabler of Zero Trust across IT, OT, IoT, and IIoT environments. With the growing complexity and interconnectivity of modern systems, particularly in critical infrastructure, the ability to apply fine-grained controls at the network, application, process, and user levels has become increasingly essential. Microsegmentation supports threat containment and breach isolation, while also enhancing regulatory compliance and operational resilience. This paper provides a technical and strategic roadmap for implementing microsegmentation using multiple enforcement models, analyzes deployment trade-offs, and outlines maturity levels to guide adoption. The discussion is grounded in real-world applications across hybrid environments, including securing industrial control systems and dynamic cloud-native architectures. The paper also considers emerging agentic AI environments, where agents, tools, APIs, models, and data services require explicit communication boundaries, governed egress, and continuous validation to avoid recreating broad implicit trust paths.