Perimeter Security
Also known as: Network Perimeter Security
Definition
Perimeter security is the set of controls that manages access, traffic, and threats at the outer boundary of a trusted network or operational zone.
Key Points
- It defines and enforces trust boundaries.
- It combines filtering, detection, and identity controls.
- It reduces exposure of critical internal assets.
- It is a common design pattern in OT and enterprise networks.
- It works best when segmentation and monitoring are aligned.
Concept
Perimeter security usually combines packet filtering, intrusion detection, identity assurance, and segmentation. The goal is to reduce the attack surface and keep hostile traffic from reaching sensitive zones. In industrial settings, the perimeter is often layered rather than singular because the edge between IT and OT is operationally more complex than a simple internet gateway.
Explainer
Perimeter controls still matter even when zero trust is the long-term goal. Many facilities and remote sites have legacy devices, fixed zones, and safety constraints that require a clear boundary model. The boundary is only effective, however, if the rules are consistently applied and the monitoring layer can tell the difference between normal industrial traffic and an attack.
Cite this entry
Perimeter Security. ConnectedEarth Knowledge Base. https://connectedearth.space/knowledge-base/perimeter-security/ (updated 13 September 2026).