What would you typically use to protect a network from unauthorized traffic between virtual machines?

A virtual firewall is specifically designed to protect networks within virtual environments, such as those involving multiple virtual machines (VMs). It operates much like a traditional firewall but is tailored for virtualized infrastructure, providing security by monitoring and controlling inbound and outbound traffic between VMs. This ensures that only authorized communication is allowed, helping to prevent unauthorized access and potential attacks that could compromise the entire virtualized network.

The other options presented do not fulfill the role of securing traffic specifically between virtual machines. A digitizer is primarily associated with converting physical media to digital formats; a virtual network interface pertains to the networking capabilities of the virtual machines but does not provide security features; and a smart card reader is used for authentication rather than network protection. Therefore, a virtual firewall is the most suitable choice for safeguarding virtual machine traffic from unauthorized access.