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11/07/2026 8:27 pm
TL;DR: Operational technology environments need identity-aware, protocol-aware Zero Trust because VPNs and static perimeters over-provision access and leave persistent tunnels that attackers can exploit, according to Appgate. The governance challenge is not whether Zero Trust applies to OT, but whether access policy, segmentation, and operational resilience are designed for legacy systems and human workflows.
NHIMG editorial — based on content published by Appgate: A Zero Trust blueprint for operational technology system security
Questions worth separating out
Q: What breaks when OT remote access relies on VPNs and broad network trust?
A: OT remote access breaks down when a single connection grants too much reach.
Q: When should organisations prioritise Zero Trust for OT over perimeter upgrades?
A: Organisations should prioritise Zero Trust when OT access is still mediated by persistent tunnels, shared paths, or third-party connections.
Q: What do security teams get wrong about segmentation in OT environments?
A: Teams often assume segmentation is just a network design exercise.
Practitioner guidance
- Replace persistent VPN reach with scoped remote access Constrain OT remote access to the specific asset, protocol, and task required.
- Build a protocol-aware segmentation map Document which OT protocols and devices must communicate, then segment around those dependencies rather than subnets alone.
- Separate policy design from technical rollout Use a phased programme that first defines access policy for critical assets, then deploys the enabling controls.
What's in the full article
Appgate's full white paper covers the operational detail this post intentionally leaves for the source:
- A four-phase OT Zero Trust blueprint with assessment, strategy, roadmap, and execution steps.
- Specific criteria for OT-ready access control, including protocol awareness, localized enforcement, and high availability.
- Examples of how policy simulation can reduce disruption before enforcement begins.
- The operational reasoning behind encrypted micro-segmentation in legacy industrial networks.
👉 Read Appgate's white paper on a Zero Trust blueprint for OT security →
Zero trust for OT systems: what it means for access control?
Explore further
11/07/2026 8:57 pm
OT identity governance fails when remote access is treated as a network problem rather than an access problem. The article shows why VPNs and static perimeters are structurally weak in environments that depend on persistent industrial systems and third-party support. For IAM and PAM teams, the lesson is that OT governance must scope who or what can connect, for how long, and to which protocol or asset. The practitioner conclusion is simple: eliminate standing reach before you try to harden the perimeter.
A question worth separating out:
Q: Who is accountable when OT Zero Trust changes disrupt production workflows?
A: Accountability sits with the programme owners who approve the operating model, not only with network or OT engineering teams. If Zero Trust changes affect production, the issue is usually weak change governance or missing stakeholder alignment. Resilience, access policy, and operational sign-off need to be owned together so security controls do not become a source of avoidable downtime.
👉 Read our full editorial: Zero trust for OT security needs identity-aware enforcement
