virtual server(A virtual computer that resides on a Hypertext Transfer Protocol (HTTP) server but appears to the user as a separate HTTP server. Several virtual servers can reside on one computer, each capable of running its own programs and each with individualized access to input and peripheral devices. Each virtual server has its own domain name and IP address, and each appears to the user as an individual Web site or File Transfer Protocol (FTP) site. Some Internet service providers (ISPs) use virtual servers for those clients who want to use their own domain names; In a server cluster, a collection of services that appear to clients as a physical Windows-based server but are not associated with a specific server. A virtual server is typically a resource group that contains all of the resources needed to run a particular application and that can be failed over like any other resource group. All virtual servers must include a Network Name resource and an IP Address resource)