Sorry for my bad english.I have routerboard RB450G.Get internet from ISP by pppoe on WAN - port 1.Port 2,3,4 and 5 is bridge.After bridge i have Nanostation 2.On Nanostation 2 i have 5-6 clients with laptops.Internet on this laptops is perfect,but from RB450G to Nanostation dont have ping.Dont have ping from Nanostation to RB450G.Where is problem?

Maybe you have a NAT for everything that goes out from the 450G, but you shouldn't be doing NAT if you want to reach your internal LAN, and that includes the nanostation and laptops.

Disable the NAT rule, reboot the 450G (to flush the NAT table) and try again.

Thanks.But how disable NAT for Nanostation?

I haven't used a nanostation, sou I can't help on that... I thought that nanostation was taking care of the wifi access/hotspot and the 450G was dealing with nat/firewall/routing.