Extended Airport Extreme Ethernet ports not assigning IP address.

Is a way I can make the Airport Extreme assign the IP address?

Both of the "extending" AirPorts.....the AirPort Extreme and AirPort Express.....are in Bridge Mode when they "extend a wireless network". DHCP (the process of assigning IP addresses..... is turned off when a device is in Bridge Mode........to it is up to your "main" AirPort Extreme to assign all IP addresses for network devices.

The "extending" AirPorts simply pass through the IP address information to connected devices.....the "extending" devices do not assign IP addresses themselves.

Since the AirPort Express is working correctly, it appears that the "extending" AirPort Extreme is the culprit. Based on what you have told us, it would appear as if the Ethernet switch on the device is not operating correctly. We need to know more about this device though, before we jump to conclusions.

1) Is this a newer "tower" version of the AirPort Extreme or an older "flat" or "square" version of the Extreme? If is the older version, we need the model number from the bottom of the device. It starts with an "A" followed by four numbers.

2) When you connect an Ethernet cable to one of the Ethernet ports on the extending Extreme, does the small green light next to the port light up?

3) What operating system are you using on the Mac or PC that you are using to configure the AirPorts?

OK, thanks for the info.

If the AirPort Extreme is setup to "extend" a wireless network, then all of the Ethernet ports on the device behave as LAN ports and all of them are enabled.

We asked what operating system you were using on your Mac, but will guess that it is a recent version. So, please check the following:

Open AirPort Utility on the Mac.......(Finder > Applications > Utilities > AirPort Utility)

Click on the picture of the AirPort Extreme

Look in the smaller window that appears to see if there is a listing for Status. If there is, what is the message there?

Otherwise, click Edit in the smaller window

Click the Wireless tab at the top of the window

Check the setting for Network Mode. It should be set to "Extend a wireless network"

If that is the setting, connect a short, spare Ethernet cable.....an length will do.....from one of the LAN <--> ports to the Ethernet port on a computer. Turn off the wireless on the computer and check to see if you can get a good Internet connection that way. If you can, then you know that the Ethernet port on the AirPort Extreme is working correctly, and you have a problem somewhere else.

If you cannot get an Internet connection when you run the test just above, try another Ethernet cable or two just to be sure that you do not have a bad cable......which happens all the time.

If the Ethernet connection is still not working, power off the "main" and "remote" AirPort Extremes, wait a minute, power up the "main" Extreme and let it run 2-3 minutes, then power up the "extending" Extreme and check it again.

If things still do not work, then you likely have an AirPort Extreme with a defective Ethernet switch. Check the ports to see if any of the will work. If not, you will need to exchange the AirPort Extreme.