Double NAT issues

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Level 1

139 points

Double NAT issues

I have just switched ISPs and my AE is showing a double NAT condition. I am getting nice high rates from the ISP. Do I need to worry about this and if so, how do I diagnose it.

Thanks,

Jim

Mac Pro, Mac OS X (10.7.5)

Posted on Apr 23, 2014 1:26 PM

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Answer 1

Apr 23, 2014 1:31 PM in response to Jim Wilkins

If you have Double NAT, the problem is already diagnosed. You have two devices both trying to be routers, when you should have only one.

Change your AirPort Extreme to Bridge Mode.

To do that, open Macintosh HD > Applications > Utilities > AirPort Utility

Click on the AirPort Extreme picture, then click Edit in the smaller window

Click the Network tab at thet top of the next window

Change the setting for Router Mode to "Off (Bridge Mode)"

Click Update, and wait a full minute for the AirPort Extreme to restart

Should be a nice green light there now.

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Answer 2

Jim Wilkins Author

Level 1

139 points

Apr 23, 2014 2:20 PM in response to Bob Timmons

Hey Bob,

THere is a beautiful green light. However the internet shows disconnected. Sigh.

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Answer 3

Apr 23, 2014 3:12 PM in response to Jim Wilkins

Power off both your ISP modem/router and the AirPort Extreme

Wait a minute or two

Power up the ISP router first, and let it run a minute

Then, power up the AirPort Extreme

If you are still having difficulties, we need to know the make and model of the "modem"......(which is a modem/router or gateway)......that your ISP has provided for you.

Unfortunately, the old saying comes back to haunt us all the time. It goes something like this......

Change just one thing on a network.......and everything else on the network will change.

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Answer 4

Jim Wilkins Author

Level 1

139 points

Apr 23, 2014 7:09 PM in response to Bob Timmons

I am using a land based system in which the internetservice is routed from stragically placed LOS antennas. My hookup is from an antenna collection point which is then relayed to a receiver attachedto my house. There is cable that runs from this receiver to my AE. I have no control over the receiver, at least I don't think I do. I get cable rates from this setup, unlike the Hughesnet rates from the satellite. The Hughesnet set up did not have this double NAT setup. I am clueless as this comms stuff so I really need your inputs.

Thanks,

Jim

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Answer 5

Apr 23, 2014 7:44 PM in response to Jim Wilkins

Sorry, I am not familiar with your type of setup, but it appears that with no actual "modem" in the system, that you may have to live with the Double NAT error that is occurring on the network.

Normally, Double NAT appears on a network when there are two routers both providing NAT services. The solution in normal cases is to place the "downstream" router in Bridge Mode, which turns off both NAT and DHCP addressing.

There is an option in AirPort Utility to click to "ignore" the Double NAT error, so the AirPort will display a green light despite the "error". You may want to try the setup that way for a week or two to see how things perform.

If all seems well, then leave things "as is". It is possible that you really have no other choice but to do this.

If you want to know a bit more about Double NAT, you can click the link just below:

http://graemenoble.id.au/post/48695277030/double-nat-explained-and-possible-solu tions

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