A virtual switch is software that connects a host, virtual machine, or simulator to network traffic paths, much like a physical Ethernet switch connects devices on a LAN. It can forward frames between virtual interfaces, host adapters, and external networks, and it is often used in virtualization, labs, and industrial simulation environments.
In cyber security, a virtual switch matters because it defines whether a system is isolated or network-facing. If a simulator or VM is bridged through a virtual switch, it may receive real multicast, broadcast, or untrusted local traffic. That creates an attack surface for resource exhaustion, denial of service, or lateral movement. Defenders reduce risk by disabling unnecessary bindings, keeping systems in local-only mode when possible, segmenting traffic, and filtering multicast on the host network.