Airport Extreme Guest Network DHCP problem

Question

Airport Extreme Guest Network DHCP problem

I can’t tell whether other people have this problem.

I have an AT&T Uverse modem with WiFi disabled. An Airport Extreme connects to it via Ethernet and creates the WiFi network in my house. An Airport Express on the 2nd floor extends the Extreme's WiFi network. (I used to have the WiFi network created by the Uverse modem but that was unreliable, with the Express dropping off the network every several days or so.)

I'm now trying to add a guest network, created by the Extreme, via Airport Utility. That seems to have worked, but when I connect to the guest network I fail to get an IP address assigned.

Is there a fix or workaround?

MacBook Pro (Retina, 15-inch, Early 2013), OS X Yosemite (10.10.2)

Posted on May 4, 2016 7:51 PM

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Answer 1

May 4, 2016 8:02 PM in response to Daniel Kaplan

Unfortunately, you have an AT&T modem/router, also called a gateway device which combines the functions of a separate modem and separate router in one single package. As such, the the device that you call your "modem" is already acting as the main router for your network.

In order for the Guest Network feature to work correctly on an Apple router, the Apple device needs to be the "main" router on the network, but it cannot assume that role, since the At&T modem/router is already performing those duties.

A bit more technical explanation would be that since your AT&T modem/router is acting as the router for your network, the AirPort Extreme needs to be configured in Bridge Mode to avoid a situation where you would have two devices that were both trying to act as routers on the same network. Not a good situation.

IF......it were possible to configure the AT&T modem/router to act only as a simple modem (I do not think it is possible, but you could ask AT&T support about that to confirm).......then.....the AirPort Extreme could assume that main router role on your network and the Guest Network feature would work correctly.

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Answer 2

May 4, 2016 8:13 PM in response to Bob Timmons

Thanks, Bob! I saw that reply from you to other queries as well but was too ignorant to understand whether it applied to my situation. Since it does, I'll contact AT&T about it.

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Answer 3

May 4, 2016 8:21 PM in response to Daniel Kaplan

Unless AT&T has just introduced a new product that I don't know about, I would not expect that AT&T would be able to help you.

Good luck, though.

The bottom line......you really need a modem that looks like the example below........(only one Ethernet port)......and I don't think that AT&T offers anything like this.

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Answer 4

May 4, 2016 8:51 PM in response to Bob Timmons

Good news! I asked AT&T how to configure the Uverse modem/router as a simple modem, and they researched it and instructed me accordingly. I did it and it seems to be working fine - I now have a working guest network! I believe the process simply involved setting it to "Passthrough" mode and assigning a fixed IP address to my Airport Extreme.

The Uverse device in question is fairly new: a Motorola NVG510, not one of the old 2Wire ones.

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