What is Virtual Server?
Virtual Server is a technology that allows multiple independent Web sites to be hosted on a single Web server. A virtual server is sometimes referred to as a Web site.
Internet Information Services (IIS) supports virtual servers in three ways:
- By binding multiple IP addresses to the server’s network interface card (NIC). Each virtual server can be assigned its own unique IP address. DNS servers can then resolve domain names into their respective IP addresses, allowing multiple companies to host their Web sites on a single IIS server. This is the preferred method if a large pool of available IP addresses exists for the server.
- By using a single IP address but assigning a unique port number to each virtual server. Clients must know the exact port number to connect to the server instead of using the default Hypertext Transfer Protocol (HTTP) port number 80.
- By enabling host headers on the IIS server. The server has only one IP address and uses the default HTTP port number 80. The client Web browser attempting to access a Web site on the IIS server must be HTTP 1.1–compliant to seamlessly access the site.
The term “virtual server” is also used in Microsoft Cluster Server (MSCS), where it is a collection of services that appears to clients as a physical Microsoft Windows NT Server. The same terminology is also used in the Windows Clustering component of Microsoft Windows 2000 Server. A virtual server is usually a resource group that contains all the resources necessary for running an application, including the network name and IP address resources.