[ale] Question about apache virtual hosts

[Jim]

What I'm trying to do is set up freedns' concept of a subdomain.  I
think there may be more than one definition.  Anyway I have a freedns
account and have established a subdomain of sub.maindomain.com which
points to the same ip as maindomain.com.

In apache I have the following:
NameVirtualHost 69.93.127.xxx:80

<VirtualHost 69.93.127.xxx:80>
    DocumentRoot /home/k4gvo/public_html/
    ServerName k4gvo.maindomain.com
    <Directory /home/k4gvo/public_html/>
        AllowOverride All
        Options FollowSymLinks
        Order allow,deny
        Allow from All
    </Directory>
</VirtualHost>

What works is when I go to http://k4gvo.maindomain.com I see what I
expect to see, the web page in k4gvo's public_html directory. 

What doesn't work is when I go to http://maindomain.com I see the same
thing, not what is in /var/www.

What did I miss?

Some things have been changed to protect the innocent.
Thanks,
Jim.