Virtual Host

A virtual host is a configuration enabling a single host machine to resemble multiple host machines. It consists of a host alias or aliases, which consist of a host name and a port number. If you specify an asterisk (*) as a host name, all host names and IP addresses that the Web server can receive will be mapped to that virtual host.
There are two virtual hosts defined during installation: default_host and admin_host.


• The default_host virtual host is intended for access to user applications, either through the HTTP transport or through a Web server. At installation time, it is configured as the default virtual host for the server1 application server. It is configured to match requests to ports 80, 9080, and 9443 for any host name.


• The admin_host virtual host is used for access to the WebSphere administrative console. It is configured to match requests to the secure ports 9090 (HTTP transport) and 9043 (Web server) for any host name.


• The proxy_host virtual host includes default port definitions, port 80 and 443, which are typically initialized as part of the proxy server initialization. Use this proxy host as appropriate with routing rules associated with the proxy server.

When you install an application, you associate a virtual host with each Web module in the application. By associating a virtual host with a Web module, requests that match the host aliases for the virtual host should be processed by servlets/JSPs in this Web module. The Web server plug-in also checks the URI of the request against the URIs for the Web module to determine whether the Web module can handle them or not.

A single virtual host can be associated with multiple Web modules unless each application has unique URIs. If there are same URIs among applications, different virtual hosts must be created and associated with each of the applications.