Listen xxx.xxx.xxx.xxx:80
Listen 192.168.xxx.xxx:80

<VirtualHost xxx.xxx.xxx.xxx:80>
   <Location />
      AuthType Basic
      ...
   </Location>
</VirtualHost>

<VirtualHost 192.168.xxx.xxx:80>
   <Location />
      #AuthType Basic
      ...
   </Location>
</VirtualHost>