oh well… I got it… I have to convert the router wireless in access point…
my config was:
ISP----MODEM ----IPFIRE—ROUTER WIRELESS—hosts
now is:
ISP—MODEM—IPFIRE—AP—hosts
I used this guide , How To Convert a Wireless Router into an Access Point - SmallNetBuilder thanks !!!
The modem(DOCSIS) looks like is already in bridged mode.