apache subdomain setup

[javasac]

Basically, I have a php application running on apache and want that any URL like x.abc.com [x can be anything] works. I can trap the URL and take action based on value of x.

 

I came to know that entry in hosts file like *.abc.com does not work.

Is there a way we can do it in apache?

 

Tried this and other variations.

 

<VirtualHost 127.0.0.1>

DocumentRoot "c:/wamp/www/yojoe-web/html"

ServerAlias *.abc.com

RewriteEngine on

RewriteCond %{HTTP_HOST} !^www.* [NC]

</VirtualHost>

 

Can someone please give me complete config?

 

Thanks,

Sachin