What is Network Segmentation?

Definition

Network segmentation is the practice of dividing a network into smaller, isolated segments — often using VLANs and firewall rules — so that traffic in one segment is separated from another. Common segments include corporate, guest, IoT, and sensitive systems.

Segmentation controls how devices communicate, applying least-privilege rules between segments so only authorised traffic is allowed to cross.

Why it matters

Segmentation limits the blast radius of a security incident: if one segment is compromised, the attacker cannot easily reach the rest of the network. It also improves performance by containing traffic and simplifies compliance.