When a user requests a resource, WebSphere Application Server tries to map the request to an alias of a defined virtual host.
Version 4.0 introduces support for wildcard entries for aliases by port. You can specify that all valid hostname and address combinations on a particular port map to a particular virtual host.
Mappings are case insensitive, but the match must be alphabetically exact. Also, different port numbers are treated as different aliases.
For example, the request
http://www.myhost.com/myservletmaps successfully to
http://WWW.MYHOST.COM/MYSERVLETand to
http://Www.Myhost.Com/Myservlet
But it does not map successfully to
http://myhost/myservletor to
http://myhost:9876/myservlet
If a user requests a resource using an alias that cannot be mapped to an alias of a defined virtual host, the user will receive a 404 error in the browser used to issue the request. A message will state that the virtual host could not be found.