TWC Motorola SBG6580 and Airport Extreme

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TWC Motorola SBG6580 and Airport Extreme

So Time Warner came out and installed a Motorola SBG6580 in my home (Docsis 3.0) to allow me to receive their Wideband Internet offering (50 down / 5 up) but i'm having huge problem with how it fits into my network.

I have an Airport Extreme and 2 Airport Expresses. Now the main problem is the Motorola Cable Modem is both a modem and a router. I want it to just act as a modem.

I called TWC and they told me to disable NAPT mode, which puts it into a state where it just acts as a modem. Great, that sounds good.

I went ahead and did that but when I rebooted the whole network it only allowed 1 computer to connect. None of my iPads or iPhones or Xbox could access the network anymore. (My Airport is on Firmware 7.6).

Why is only 1 computer able to access the new network? What am I missing?

Posted on Dec 11, 2011 6:41 AM

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Answer 1

Dec 11, 2011 6:50 AM in response to Arzenal

Arzenal wrote:

I went ahead and (disabled NAPT mode) but when I rebooted the whole network it only allowed 1 computer to connect.

That makes perfect sense. There needs to be a router in provide "NAT" functionality to support a connection by more than one device. You seem to have an AirPort Extreme but haven't mentioned trying to connect it directly to the TW device. That's what you need to do. Further, the Extreme needs to be configured to create a wireless network.

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Answer 2

Arzenal Author

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Dec 11, 2011 6:58 AM in response to William-Boyd-Jr

Once I disabled NAPT mode I hooked my Airport Extreme back to the cable modem and created my network.

The one device I managed to connect was over wifi on the network. It's just that only 1 device could connect. Which is bizarre.

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Answer 3

Dec 11, 2011 7:09 AM in response to Arzenal

I could imagine configuring an AirPort Extreme ot support only one device by configuring DHCP to issue only one IP address, although I'd expect that to be hard to do by accident. Could the Extreme be in "bridge" mode? That could explain the problem. Look for that setting in the "Internet Connection" panel.

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Answer 4

Arzenal Author

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Dec 11, 2011 7:11 AM in response to William-Boyd-Jr

I think it was in Bridge Mode (off). What should it be in..."Distribute a range of IP addresses" ??

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Answer 5

Dec 11, 2011 7:28 AM in response to Arzenal

Edit: If you see an option of "Share a Public IP Address" you should choose that.

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Answer 6

Arzenal Author

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Dec 11, 2011 7:37 AM in response to William-Boyd-Jr

That's what I just did. Switched from Bridge Mode to "Share a Public IP address" and it seems to have worked, all the devices now see the network and the modem is in NAPT disabled mode.

You saved me on this glorious Sunday morning, Merry Christmas.

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Answer 7

Arzenal Author

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Dec 11, 2011 7:53 AM in response to Arzenal

Now I just need to figure out how to port Forward here..

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Answer 8

Dec 11, 2011 12:58 PM in response to Arzenal

Port forwarding is done in the "Port Forwarding" tab of the "Advanced" pane of AirPort Utility. The details can be a little tricky.

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Answer 9

Imagine

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May 1, 2012 12:04 PM in response to Arzenal

Hi Arzenal,

Did you ever resolve this? Did you ever get the SBG6580 to work with the AE and AX?

Thanks!

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Answer 10

Arzenal Author

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May 2, 2012 6:36 AM in response to Imagine

Yes, solved by this thread.

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Answer 11

Imagine

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May 2, 2012 12:17 PM in response to Arzenal

I'm a little confused though. Aiport Utility 6.0 has it where you can "Ignore" the NAT on the Extreme. What's the difference between Ignoring NAT on the Extreme or the SBG6580?

lso, how did you Ignore Nat on the SBG6580?

Thanks again!

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Answer 12

Aug 28, 2012 9:27 PM in response to Arzenal

I've got a similar problem -- using a SBG6580 as a cable modem and an Airport Extreme for wireless ... I am constantly resetting the network as each device seems to get kicked off regularly. Even my Mac which is connected directly to the SBG6580 via ethernet.

The problem is that TWC does not allow me to access the router, so I can't disable NAPT. Has anyone figured out a way around this?

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