Network Segmentation

Welcome to the Network Segmentation Playbook on TAGSIA. This section is your authoritative, vendor-neutral guide to designing and implementing secure digital boundaries onboard your vessel.

In the complex environment of a mixed-age fleet, Network Segmentation is the single most critical security control you can deploy. It’s the digital equivalent of watertight bulkheads: it ensures that a breach in a less-secure zone (like crew IT) cannot immediately spread to disable or compromise safety-critical systems (like navigation or propulsion control).

This section moves beyond theory to provide pragmatic, ship-specific implementation patterns aligned with global maritime regulations and standards.

network segmentation

What You Will Find Here

The Network Segmentation Playbook is dedicated to helping Superintendents, ETOs, and CSOs achieve effective isolation using existing or cost-effective hardware.

1. âš“ Regulatory Models for Segmentation

Breaks down Zones & Conduits (IACS E26 / IEC 62443) into practical, actionable network models.

High-impact retrofit plan for legacy and mixed-age fleets, focusing on separation of OT, IT, and Remote Access DMZ using existing equipment.

Guidance on rigorous system-by-system segmentation required for vessels subject to IACS UR E26 from the initial design stage.

2. 🛠️ Practical Implementation Guides

VLANs and ACLs: Step-by-step guides on using your existing Layer 3 switches and firewalls to create logical segmentation (VLANs) and enforce traffic rules (Access Control Lists).

Legacy Systems Integration: Specific advice on how to segment and protect older, unpatchable OT systems that cannot be easily updated for security.

Conduit Hardening: Techniques for securing the communication paths (conduits) between zones, including deep packet inspection and network monitoring requirements to satisfy E26 Detect requirements.

3. đź“ś Regulatory Alignment & Auditable Evidence

TAGSIA Tags: Every piece of guidance is mapped to the relevant clause in IACS UR E26 (Control 3.1) and IEC 62443-3-3 (System Requirement 1), giving you the specific evidence required for audits and class surveys.

Download the official Zones and Conduit Diagram Template to use as a starting point for documenting your vessel’s network architecture.

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