Hello to all,
in my network there are 2 adsl gateway located in two separate buildings, among them there is a wireless link made ​​with 2 RB411.
I want that if I connect a host in the building 1 I want it to connect to DHCP gateway 1, because it can happen that automatically connect to the gateway 2.
I tried to make a rule Ip / Firewall / Filter but without success.
(0 chain = forward action = drop protocol = tcp dst-port = 67-68)

Can you help?

If you have the wireless bridged to the Ethernet (I'm assuming that you do) you have to enable "use IP firewall" under the bridge settings to send the traffic through the firewall you have setup and be blocked there.

And protocol should be UDP, not TCP