I am testing out to see whats my IP address but depending on which website I used, I get different IP address. I am using a router

If I use this , My IP address is

enter image description here

If I use this , My IP address is

enter image description here

If I use this , My IP address is

enter image description here

If I use ipconfig/all , My IP address is

Why is there a variation in my IP address? Does it have something to do with DHCP???

Why does my IP address start with 202 sometimes, 218 sometimes, or 58 sometimes?

What is the true IP address of my computer??

  • are checking your ip in same session? Jan 31 '14 at 5:28
  • Are you doing these test from the same computer?
    – Darius
    Jan 31 '14 at 5:44
  • Yea from the same session and from the same computer Jan 31 '14 at 6:18

The first & second IP does not belong to you - it belongs to SGCableVision Inc.

I assume you might have heard of NAT. This allows IP's to be translated to different IP's to improve network management and also not to use all IPv4 addresses available on a subnet. Those IP's belong to your ISP. They are most likely upstream provider gateway IP - meaning some border router between the ISP and the public internet. Reversing from the border router to you, that IP is then translated to a new IP provided by a dhcp server, then again and again till it reaches your source IP.

You can see how this process forms by doing a traceroute or tracert -d from command prompt in Windows to www.google.com or

  • 1
    SGCablevision is the ISP he's using, though thats an old name they dumped - Its called Starhub now, of course it belongs to them, and no its not NAT.The first IP address there is the 'correct' one in fact, but unless you've butted heads with this problem before, you wouldn't know that
    – Journeyman Geek
    Jan 31 '14 at 7:37
  • Good point - I would kindly like to find out how it works if it's not NAT. I only pointed that out because of our own setup at the ISP where I'm working, but note we are doing wireless internet. So the setup might be different, but we have NAT rules all over to the end-user.
    – Rudolph
    Jan 31 '14 at 8:04
  • 2
    This is entirely guesswork here. Basically traffic over port 80 goes through one or more proxy servers. My guess is they use some form of load balancing, and possibly provide some degree of caching (which may explain why you always get the same IP address on detection sites), and that some sites, which don't connect through to port 80 detect IP addresses correctly. Unlike Nat or CGN, you can connect to, or out of your public IP address - I can ssh into my home servers for example, or even access a web server running on a non standard port.
    – Journeyman Geek
    Jan 31 '14 at 8:19
  • 1
    The details behind the block-list methods or kind of sketchy, as with any government mandated block. Honestly, no one outside one of the big 3 ISPs probably knows the exact details, and my answer is based entirely on local knowledge, and actual experimentation with a system on the same ISP. Quite a bit of how I worked it out is in my answer. The website I have linked in my answer sort of shows what's happening
    – Journeyman Geek
    Jan 31 '14 at 8:34
  • I'd add, if you have any ways to test for nat, let me know, and I'll add it to my answer
    – Journeyman Geek
    Jan 31 '14 at 8:34

I've used starhub before and found many of the same things. I have a few theories about this - I believe that the transparent proxy that starhub has to use to block sites on the 'symbolic' blocklist is the cause - this seems to be a requirement for all ISPs here.

The first two addresses are probably wrong, and for starhub's proxy servers. The third one is likely the correct one. I'm getting the same addresses as you for the first two. The 58.x.x.x is the one for your modem, and is how you'd reach your network from outside, with proper port forwarding.

The address is unusual, Its probably internal, but I've not seen any router use that range, or presumably use for itself. It should work between computers on your own network, but not from outside.

Its clearly not CGN since the ip addresses are not in the CGN range, they're all regular IP addresses, and starhub dosen't use CGN on cable (I have no idea about fiber optic connections). Traffic outside port 80 seems unaffected - I had in the past used a ip address detection service on an alternate port, and I routinely SSH into my home server boxen from random networks.

How do you easily check?

I'm not sure about the fibre optic plans, but for the cable plans your router is the best place to start - If its connected to a modem (Starhub uses motorola surfboards for their low end cable plans), check at your router, and if its a cisco gateway (they use these for anything better than the 'basic' plan), log into that and check. I used to have a bash script that would get the contents of my old router's startup page, and scrape that to feed into a dynamic DNS script. The modem router, or anything connected directly to the modem will report the correct IP address.

I also found that this website has a test that shows your proxy address and real IP address

That said, Starhub's services can be uniquely broken at times. One of the side effects of the transparent proxy server is it renders a lot of download-locker sites unusable, since they all detect the same IP address.

I've had routing issues with a specific, entirely SFW webcomic for months, and then it would work again. They also do nx hijacking (which involves pointing invalid domains at a starhub search portal), though thats opt out.

I'd note, interestingly, the third site dosen't pick up my IPV6 address (which starhub supports).


It looks like your ISP might be using Carrier Grade NAT - Thus your computer/router might not be reachable from parts of the Internet. (Its also possible you using some kind of vpn/ip anonymising service).

The "true address" of your computer is the 192.168 one, but, of-course, that should not work outside your network, and is translated to a "real world" address.

Pretty cool - I wonder how broken it is !!!

  • Nope, I think only the ISPs on fiber seem to use CGN.
    – Journeyman Geek
    Jan 31 '14 at 7:29

No IP address belongs to your computer. Your computer has been assigned IP address on your local network. But it has no Internet IP address, so other machines that do have to handle Internet requests for it.

"What is my IP address" really translates to "What is the public IP address you associate with this request". So it's the address of the machines that do have public IP addresses that handle your requests.


Your cable internet proivder possibly gave you an ipv6 cable modem and it's being used in Dual Stack Lite mode, which means that you don't have a public ipv4 address assigned to your modem.

In order to communicate with ipv4-only capable servers, they NAT/Proxy your ipv6 connection so that those servers can respond via ipv4, which will then get forwared to your ipv6 addressable modem.

And they are possibly redirecting your requests to specific NAT/Proxy servers, depending on their avaliability, hence the variability.

The ipv6 address in the screenshot is most probably the real ipv6 address of your modem, your public ip address, to which ipv6-capable servers will directly respond to without requiring the NAT/Proxy server.

The 192.168.x.x address is the real address of you computer, which will never be your public address. It's the address your computer has inside your local network. The other addresses are the ones of your modem / your service providers NAT/Proxy servers.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.