https://vnpro.org/forum/showthread.php/94863-M%E1%BB%8Di-ng%C6%B0%E1%BB%9Di-c%C3%B9ng-gi%E1%BA%A3i-b%C3%A0i-t%E1%BA%ADp-chia-IP-n%C3%A0y-nh%C3%A9!
