By configuring your Web server structure into multiple virtual servers, you gain finer control over the server. In other words, rather than configuring a setting for an entire server, you can configure it for just a virtual server.
You can also configure authentication on a virtual server basis, so that different virtual servers can use different authentication methods. If you have some sites that are internal to an organization and some that are accessible from the Internet, you can host them on separate virtual servers and use the appropriate authentication method for each environment.
|Virtual servers are called Web sites in Microsoft Internet Information Services (IIS).|
Using virtual servers can also allow you to isolate Web sites from one another. SharePoint Team Services supports approximately 1,000 virtual servers per server. Although Windows SharePoint Services supports only 10 to 20 virtual servers per front-end Web server, it does enable at least 10 times as many sites per server. This difference is a result of the use of ASP.NET, which creates a separate set of compiled dynamic-link libraries (DLLs) for each virtual server.