What is a VLAN?

A VLAN (virtual local area network) is a way to split one physical network into several separate networks using switch settings, so that devices in one VLAN cannot talk directly to devices in another. A company might put office PCs, guest Wi-Fi, card terminals and cameras in different VLANs, and only allow the connections each group needs. This limits how far an infection can spread. A VLAN is only as good as the rules between VLANs, usually set on the router or firewall, and those rules drift over time. Watching the traffic between segments shows whether the separation you planned actually holds.

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