Configuring AirPort Extreme with Existing Router

airportNetworkwifi

I'm setting up an office network consisting of:
– ATT ADSL2 Modem -> CISCO Router (198.x.x.x) -> Airport Extreme

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I'm having an issue getting the Airport Extreme (6th Gen) to connect to the network. I want to use the AE to serve its own 5Ghz and 2.5Ghz network. The issue isn't configuring the wireless details – it is how to get the airport to connect to the router correctly.

Upon connecting the AE as a fresh factory default device, it reports:
enter image description here

What is the correct method to setting up the Airport Extreme in this instance?
I've tried the roaming setup on Apple with no success.

Best Answer

The airport extreme should be connected as just a device with the cisco router handling DHCP and NAT. in the airport configuration go to the Network Tab and click the double headed arrow under Router Mode set it to "Off(Bridged Mode) enter image description here

You can then go to Wireless and set that how ever you want all traffic will go to the cisco router and either be forwarded to the Internet or go to the voip, printer, etc.