Finally realized that my ISP was carriage natting me, and my router's ip is really on the ISPs network and not externally facing. =(

My ISP Is doing something that is thwarting my ability to get my Airpot Extremes IPv4 addresss. When I look at it via the airport utility, I clearly can the right address. However when I use something like checkip.dyndns.org, icanhazip.com, http://www.whatsmyip.org, it gives me the wrong IPv4. Would like to use dyndns, and so far just entering in the ip manually.

Is there a way to just ask the Airport Extreme what it's external IP is via the terminal?

So I am sure this question has been asked a lot, but I believe this is a slightly different question from the one below.

How to obtain the external IPv4 address via Terminal

SO Googling what's my ip, or any of those similar solutions is not going to work because my ISP is double batting me or something.

My airport is plugged directly into the ISP.

Here is a trace route to cnn

traceroute to cnn.com (, 64 hops max, 52 byte packets
 1 (  1.947 ms  0.644 ms  1.224 ms
 2 (  3.719 ms  2.479 ms  2.487 ms
 3 (  3.990 ms  2.365 ms  3.992 ms
 4 (  3.732 ms (  3.752 ms (  2.470 ms
 5 (  15.431 ms
    25.66.208.web-pass.com (  1.995 ms (  3.590 ms
 6  x.196.247.173.web-pass.com (  3.647 ms  3.496 ms  2.737 ms
 7  x.196.247.173.web-pass.com (  3.984 ms  3.818 ms  3.727 ms
 8  v505.core1.sfo1.he.net (  14.486 ms  3.665 ms  3.969 ms
 9  10ge11-2.core1.sjc2.he.net (  5.239 ms  11.364 ms  5.228 ms
10  10ge3-2.core3.fmt2.he.net (  5.265 ms  4.872 ms  15.784 ms
11  10ge3-1.core1.dal1.he.net (  62.946 ms  74.556 ms  53.661 ms
12  10ge5-4.core1.atl1.he.net (  65.513 ms  65.322 ms  65.630 ms
  • What makes you believe that the IP address returned by icanhazip.com etc is wrong? You can for instance run traceroute cnn.com to verify, the external IP address should correspond to line 2 (assuming your Mac is directly connected to the Airport Extreme).
    – nohillside
    Aug 9, 2015 at 18:06
  • It's a different IP that my Airport Utility is saying, and when I do a port scan on it it does not have the same ports open. Aug 9, 2015 at 18:08
  • And your Airport Utility is correct because?
    – nohillside
    Aug 9, 2015 at 18:08
  • I'm not even sure APU shows the external IP, can you add a screenshot?
    – nohillside
    Aug 9, 2015 at 18:10
  • Because I can hit my web server with it. Also the two IPs show completely different ports open. Aug 9, 2015 at 18:11

1 Answer 1


Is your Airport the 'last hop' before the ISP? Straight into the modem, no other router between you & them?

If so, then asking Google 'what's my IP address?' will show it.

That address is the 'border' between you & the outside world & in fact it kind of is partly at your Airport & partly at the next hop, your ISP, insomuch as it's your last reference point, & their first.
You'd need a hardware engineer to clarify that last point - the details are beyond me, I'm afraid.

  • My router is hooked directly into the wall, so yes last hop. It used to that what's my IP address would work. It now gives a device further down stream. Aug 9, 2015 at 17:52
  • For instance, my Airport Utility tells me my IPv4 address is ..16.34 and that is what I have my domain name set too and it works. However Googling 'what's my IP address' give me something quite different...for instance ..239.200. The two IPs are not the same device machine, as running a port scan on them shows different ports open. Aug 9, 2015 at 17:55
  • a router has an internal address, starting with 192.168. or 10. [private IP address ranges, repeated around the world in every home & business] of which your internal devices will be higher last digits of that network [ for example] - & an external address, which could be anything except those numbers, a public-facing address, unique in the world - the device itself performs Network Address Translation [NAT] so one can talk to the other.
    – Tetsujin
    Aug 9, 2015 at 18:11
  • @TETSUJIN, can you update your answer to say you are likely being double natted, and there is no way to get an external IP. When I tried to hit the IPv4 that i thought was right on my iPhone, and not on my network it was unreachable. I am convinced your double natting is what is going on. Will give you the answer then. Aug 9, 2015 at 18:33
  • It looks like they are doing this to me... en.wikipedia.org/wiki/Carrier-grade_NAT Aug 9, 2015 at 18:47

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