Helo i solved my problem following this awesome tutorial:
I had many problems becouse of i tried to use ubuntu 14.04 now i’m using ubuntu 10.04 and it is working well.
I had problems configuring my mikrotik dhcp server, becouse i was trying to configure the options 66 and 67 manualy, there are specifc filds in it to configure these options, in the picture below i show the right filds:
[IMG]https://dl.dropboxusercontent.com/u/70915108/dhcp_fog_mikrotik.jpg[/IMG]