aragonx@dcsnow.com wrote:
My means :
The Server machine is not DMZ, so can it use Private IP only ?
    

Your only limitation is that a machine can NOT use an address in the
private IP range to communicate DIRECTLY to the Internet.
  
Sorry, pardon me !
If you have a router (be it hardware or software) to map your traffic to a
public IP, you can use either.
  
The router machine is a general router machine which provided by ISP, so it can't to be configed with firewall function ( only routed / routing function )...