A virtual server, sometimes called a virtual host, is an object that allows the same physical server to host multiple Internet domain names. All virtual servers hosted on the same physical server share the Internet Protocol (IP) address of that physical server. A virtual server associates a domain name for a server (such as www.aaa.com) with the particular server on which the Application Server is running.
Do not confuse an Internet domain with the administrative domain of the Application Server.
For instance, assume you want to host these domains on your physical server:
www.aaa.com www.bbb.com www.ccc.com
Assume also that www.aaa.com, www.bbb.com, and www.ccc.com have web modules web1, web2, and web3, respectively, associated with them.
This means that all of these URLs are handled by your physical server:
http://www.aaa.com:8080/web1 http://www.bbb.com:8080/web2 http://www.ccc.com:8080/web3
The first URL is mapped to virtual host www.aaa.com, the second URL is mapped to virtual host www.bbb.com, and the third is mapped to virtual host www.ccc.com.
On the other hand, the following URL results in a 404 return code, because web3 isn’t registered with www.bbb.com:
For this mapping to work, make sure that www.aaa.com, www.bbb.com, and www.ccc.com all resolve to your physical server’s IP address. They need to be registered with the DNS server for your network. In addition, on a UNIX system, add these domains to your /etc/hosts file (if the setting for hosts in your /etc/nsswitch.conf file includes files).
When the Application Server is started, it starts the following virtual servers automatically:
A virtual server named server, which hosts all user-defined web modules
A virtual server named __asadmin, which hosts all administration-related web modules (specifically, the Administration Console). This server is restricted; you cannot deploy web modules to this virtual server.
For development, testing, and deployment of web services in a non-production environment, server is often the only virtual server required. In a production environment, additional virtual servers provide hosting facilities for users and customers so that each appears to have its own web server, even though there is only one physical server.