Can I use a broadband modem or router with an AirPort Extreme or Express?

Yes, you can use a broadband cable modem or a combined modem/router with an AirPort Extreme or Express. If you are using a standalone modem, simply connect it to the WAN port of your AirPort base station using an Ethernet cable. If you are using a combined modem/router gateway provided by your ISP, it is recommended to put that device into bridge mode. This disables its internal routing functions and prevents a Double NAT error, allowing the AirPort to handle all networking tasks. Once connected, use the AirPort Utility on your Mac or iOS device to complete the setup.