Network segmentation and zero trust network access

Network segmentation and zero trust network access aim to limit who can reach what in your IT environment. Segmentation splits the network into smaller zones so sensitive systems are easier to protect. Zero trust, often written as ZTNA, means you do not trust any user or device by default. Every login and every access path is verified and limited.

When used together, they reinforce each other. If an attacker breaks into one zone, they still face many hurdles to move later. Access requests are evaluated with identity, device health, location, and the resource being asked for. This reduces the blast radius and helps you enforce least privilege and compliance.

How to start

  • Map assets and data flows: list critical apps, who uses them, and how they connect.
  • Choose an approach: network-based segmentation with VLANs and firewalls, or microsegmentation that enforces rules at the workload or device level.
  • Tie access to identity: use an identity provider, MFA, and check device health before granting access.
  • Write clear policies: define who can reach which app, from which device, under what conditions.
  • Monitor and adjust: collect logs, watch for drift, and update rules as needed.

Example: HR systems live in a dedicated segment. HR staff access them through a ZTNA gateway with MFA. Finance apps sit in a tighter zone with stricter checks. IT admins use a separate control plane that requires device posture and elevated approval.

Benefits include lower risk, easier audits, and clearer governance. Challenges are complexity, policy drift, and the need for ongoing monitoring to avoid performance or access gaps.

Starting with a simple, well-scoped project helps. Over time, you can expand microsegmentation to more workloads while keeping a strong identity-based access model.

Key Takeaways

  • Pair segmentation with zero trust to reduce blast radius and improve control.
  • Use identity, MFA, and device posture to gate every access request.
  • Start small, map data flows, and gradually extend policies across the network.