A virtual host is a configuration that enables a single host machine to resemble multiple host machines. Resources associated with one virtual host cannot share data with resources associated with another virtual host, even if the virtual hosts share the same physical machine.
Each virtual host has a logical name and a list of one or more DNS aliases by which it is known. A DNS alias is the TCP/IP hostname and port number that is used to request the servlet, for example yourHostName:80. When no port number is specified, 80 is assumed.
When a servlet request is made, the server name and port number entered into the browser are compared to a list of all known aliases in an effort to locate the correct virtual host and serve the servlet. If no match is found, an error is returned to the browser.
An application server provides a default virtual host with some common aliases, such as the machine's IP address, short host name, and fully qualified host name. The alias comprises the first part of the path for accessing a resource such as a servlet. For example, it is localhost:80 in the request...http://localhost:80/myServlet
A virtual host is not associated with a particular node (machine). It is a configuration, rather than a "live object," explaining why one can create it, but cannot start or stop it. For many users, creating virtual hosts is unnecessary because the default_host is provided.
Adding a localhost to the virtual hosts adds the host name and IP address of the localhost machine to the alias table. This allows a remote user to access the administrative console.
See alsoWhy you would use virtual hosting
The default virtual host (default_host)
How requests map to virtual host aliases
Related TasksConfigure virtual hosts