Virtual Servers

To create a virtual server you must first decide which class you want it to belong to. Next you need to decide what kind of virtual server you want. To create a virtual server, all you need to specify is a virtual server ID and one or more URL hosts.

This section includes the following topics:

• Types of Virtual Servers

• IP-Address-Based Virtual Servers

• URL-Host-Based Virtual Servers

• Default Virtual Server

Types of Virtual Servers

Prior to the version 6.0 release of Sun Java System Web Server, there were two kinds of virtual servers: hardware and software. Hardware virtual servers had unique IP addresses associated with them. Software virtual servers did not have unique IP addresses, but instead had unique URL hosts.

In Sun Java System Web Server 6.0 and Sun Java System Web Server 6.1, these concepts are no longer quite accurate. All virtual servers have a URL host specified. However, the virtual server may also be associated with an IP address based on its listen socket.

When a new request comes in, the server determines which virtual server to send it to based on the IP address or the value in the Host header. It evaluates the IP address first. For more information, see Virtual Server Selection for Request Processing.

IP-Address-Based Virtual Servers

To have multiple IP addresses on a single computer, you must map them through the operating system or provide additional cards. To set up multiple IP addresses through the operating system, use the Network Control Panel (Windows) or the ifconfig utility (UNIX/Linux).

Directions for using ifconfig vary from platform to platform. Consult your operating system documentation for more information.

Typically you create an IP-address-based virtual server by creating a listen socket that listens on a specific IP address. The listen socket’s default virtual server is an IP-address-based virtual server. For more information on ways to deploy virtual servers, see Deploying Virtual Servers.

URL-Host-Based Virtual Servers

You can set up URL-host-based virtual servers by giving them unique URL hosts. The contents of the Host request header directs the server to the correct virtual server.

For example, if you want to set up virtual servers for customers aaa, bbb, and ccc) so that each customer can have an individual domain name, you first configure DNS to recognize that each customer’s URL, www.aaa.com, www.bbb.com, www.ccc.com , resolves to the IP address of the listen socket you are using. You then set the URL hosts for each virtual server to the correct setting (for example, www.aaa.com).

Because URL-Host-based virtual servers use the Host request header to direct the user to the correct page, not all client software works with them. Older client software that does not support the HTTP Host header does not work. These clients will receive the default virtual server for the listen socket.

Default Virtual Server

URL-Host-based virtual servers are selected using the Host request header. If the end user’s browser does not send the Host header, or if the server cannot find the specified Host header, the default virtual server services the request.

The default virtual server is set by listen socket. You specify a default virtual server when you create a listen socket. You can always change the default virtual server.