Explanation/Reference:
Section: Considerations for Expanding an Existing Network Explanation
Explanation:
Antivirus software should be installed on the host and on each virtual machine (VM) in order to fully protect the system. A VM is an isolated environment running a separate operating system (OS) while sharing hardware resources with a host machine's OS. For example, you can configure a Windows 7 VM that can run within Windows 8; both OSs can run at the same time if virtualization software, such as Microsoft Hyper-V, is used. Depending on a computer's hardware capabilities, multiple VMs can be installed on a single computer, which can help provide more efficient utilization of hardware resources. For example, VMWare ESXi Server provides a hypervisor that runs on bare metal, meaning without a host OS, and that can efficiently manage multiple VMs on a single server.
Although a VM shares the hardware resources of the host computer, the OSs do not share software resources. Therefore, software installed on the host is not accessible from within the VM. For example, Microsoft Office might be installed on the host computer, but in order to access Microsoft Office from within a VM, you must also install Microsoft Office on the VM. Separate instances of software on the host computer and on each VM can help protect the host computer from potentially harmful changes made within a VM. For example, if a VM user accidentally deletes a system file or installs malicious software, the host computer will not be affected. Therefore, the user can safely shut down the affected VM without compromising the host.
Installing virus protection on the host computer will not automatically protect any VMs running on that host computer. In addition, installing virus protection on any one of the VMs will not protect the host or any other VM on the host. You must manually manage the security of the host and of each VM that is installed on a host computer. For example, installing patches and security software on the host computer will not apply those same patches and software to the VMs. This applies to drivers as well? if the network adapter driver is updated on one VM, the host computer and the other VMs are not similarly updated.
Reference:
CCDA 200-310 Official Cert Guide, Chapter 4, Server Virtualization, p. 155