No, @ericsch is correct, you need to turn your modem into pass through mode. The modem doesn't care about security as such, the router does and your Netgear router should have a firewall built in. As I mentioned before, you turn that off by hitting the modem setup page in the browser. Once it is off, the only way to connect to the router is to either reset it to factory settings or connect via ethernet to a computer.
Then let the Netgear handle all the routing and security.