virtual server

(1) See server virtualization. Contrast with virtual host.

(2) A virtual machine environment from Microsoft for Windows servers. See Microsoft Virtual Server.

(3) Multiple servers that appear as one system image to the operating system or to the network administrator. See network virtualization.

(4) Multiple servers that appear as one server for load balancing. For example, all clients use the IP address of the virtual server, which uses address translation to point to a real server based on its load balancing algorithm.

Load Balancing

For load balancing, all clients use the address of the virtual server, which is substituted with the address of one of the real servers. The selection algorithm could be simple round robin or based on the current load of the servers.

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(World-Wide Web)

virtual server - A configuration of a World-Wide Web server that appears to clients as an independent server but which is actually running on a computer that is shared by any number of other virtual servers. Each virtual server can be configured as an independent website, with its own hostname, content, and security settings. DNS maps the hostnames of all virtual servers on one physical server to its IP address. The web server software then uses the "Host" header in the HTTP request to determine which virtual server the request was for, and then processes the request using that virtual server's configuration. Virtual servers allow Internet Service Providers to share one computer between multiple websites while allowing the owner of each website to use and administer the server as though they had complete control.