Which technology allows multiple virtual networks on a single physical network?

VLAN, or Virtual Local Area Network, is the appropriate choice for enabling multiple virtual networks to operate on a single physical network. It achieves this by logically segmenting the network, allowing for different broadcast domains within the same physical infrastructure. This segmentation improves network performance, enhances security by isolating traffic, and simplifies management by allowing network administrators to group devices based on functional needs rather than their physical location.

Each VLAN is identified by a unique identifier, which enables switches to manage traffic efficiently among devices in different VLANs. This means that devices within the same VLAN can communicate with each other directly, while devices in different VLANs require a router or a Layer 3 switch for communication, providing an extra layer of control and security.

In contrast, other technologies mentioned serve different purposes. A VPN focuses on creating secure connections over the internet, typically for remote access or secure site-to-site communication, but it does not inherently create multiple virtual networks within a single physical infrastructure. WAN relates more to wide-area connectivity between disparate geographic locations and is not concerned with virtualizing network segments. NAS is a storage solution and does not relate directly to the concept of virtual networks.