Which device can support multiple networks on each of its interfaces?

A virtual router can support multiple networks on each of its interfaces due to its ability to create logical routers on a single physical device. This technology allows for virtualization, where separate routing environments can be set up independently, enabling the management of multiple networks. Each virtual router can handle different IP ranges or even different routing protocols, providing flexibility in network design and resource utilization.

In contrast, a physical router operates based on its hardware and typically supports a limited number of networks and interfaces, as it is bound by its physical capabilities. A network switch primarily facilitates communication within a single network rather than routing between multiple networks, while a firewall is designed to control access and traffic based on security rules, rather than managing multiple networking environments in the way that a virtual router does.