What is Microsegmentation?

What it does

Microsegmentation enforces east-west traffic controls between workloads inside a network. Where a traditional firewall guards the perimeter, microsegmentation controls traffic between servers, containers, and services that already sit inside that perimeter.

Tools in this category typically:

• Apply allow-list policies at the workload, process, or service level
• Block lateral movement between workloads that have no reason to communicate
• Enforce mutual TLS (mTLS) between services to verify identity on every connection
• Test whether isolation policies are actually working by probing for unexpected traffic paths
• Operate with or without agents installed on each host

Why teams buy it

A compromised workload in a flat network can reach almost anything else on that network. Microsegmentation shrinks the blast radius. If an attacker lands on one server, policy blocks them from pivoting to databases, payment systems, or other sensitive workloads.

Regulatory frameworks such as PCI DSS and HIPAA require network segmentation. Microsegmentation satisfies those requirements at a finer grain than VLAN-based separation.

Teams also use it to enforce zero trust principles inside the data center, where Zero Trust Network Access (ZTNA) tools typically stop at the perimeter.

What to look for

• Deployment model: Agent-based tools offer deep visibility; agentless tools are faster to deploy but may have less granular control.
• Policy discovery: The tool should map existing workload communication before you write rules, so you do not break production traffic.
• Enforcement point: Some tools push policy to host firewalls, others use a service mesh or hardware controls.
• Look for continuous testing that confirms isolation is holding, not just that policies are configured.