VLAN segmentation is a way to divide one physical network into multiple logical networks, called VLANs. Devices in different VLANs are separated at Layer 2, so broadcasts and most traffic do not flow freely between them unless routing or firewall rules allow it. This helps limit exposure if one user, device, or wireless guest is compromised.
In cyber security, VLAN segmentation supports least privilege and containment. Organizations use it to isolate staff, guests, servers, VoIP phones, and IoT devices, reducing the chance that an attacker can move laterally across the network. In real defenses, VLANs are usually paired with access control lists, firewalls, and wireless policies. Misconfigured VLANs, trunk ports, or switch rules can weaken the boundary, so segmentation must be tested and maintained carefully.