Active scanners that are created using virtual machine technology generally follow the same strategy as physical machines with some minor differences. Virtual machines can be deployed much faster in many locations with less reliance on WAN links. The locations chosen to not have a virtual machine are those that do not have hardware, personnel, and licensed software sufficient to support them. On the other hand, each instance requires a license, maintenance, and support so the number should be kept to a minimum.

It will also be important to get a clear definition of the hardware requirements to operate a virtual machine. Most vendors have ported the software that typically runs on an appliance to a virtual machine. Doing so can have unpredictable performance results when the host OS running virtual-machine software separates the scanner from the hardware. A completely separate round of testing is in order for a virtual version of a hardware product.

Sometimes, it is more practical to use both a physical appliance and a virtual appliance rather than just one. This is especially true when shipping a product from one place to another is impractical. Furthermore, rack space and power consumption can be problematic for devices that are used only during business hours for auditing desktops, or only at night for auditing servers. The growing emphasis on power conservation makes the prospect of virtual appliances appealing to senior management.