Network segmentation reduces blast radius by placing meaningful control points between systems, users, applications, and trust zones. But segmentation only works when the firewall policies enforcing those boundaries remain accurate over time.
Common weaknesses include broad inter-zone rules, legacy access between old and new application tiers, management services exposed across too many networks, and object groups that no longer reflect the real environment. These issues can make a segmented design look stronger on paper than it is in production.
Continuous or scheduled firewall auditing helps teams catch segmentation drift earlier. Instead of waiting for an incident or annual review, engineers can regularly check whether the firewall still supports the intended security architecture.