What is my actual IP address?

I understand 192.168.x.x is our local IP address, and the public IP is some other. I used this site to get my IP, and the result:

But in my official ISP's site and my Router's login, it is as follows:

My router and ISP shows my an IP, while the website shows me another IP. What is my actual IP address? And why am I assigned multiple IP addresses?

I am asking so that another computer can establish a connection with my computer, as I wrote a java program for that

Siddharth Venu

Posted 2016-08-13T15:09:11.727

Reputation: 301

Your ISP is likely using Carrier Grade NAT.

– DavidPostill – 2016-08-13T15:11:04.477

3@DavidPostill as someone who uses the same ISP as OP, can confirm – Sathyajith Bhat – 2016-08-13T15:11:28.817

So what is likely to be my actual IP? (I am asking so that another computer can establish a connection with my computer, as I wrote a java program for that). – Siddharth Venu – 2016-08-13T15:12:23.603

@Sathya Nice to know I'm right again :) – DavidPostill – 2016-08-13T15:12:48.630

@SiddharthVenu Please read Alternatives to Port Forwarding & NAT: "There are four major problems that you may run into that would require alternatives to port forwarding. " ...

– DavidPostill – 2016-08-13T15:13:13.397

@DavidPostill so I cant use that 49.xx.xx.xx as there are many ISP customers sharing the same IP. So could I use the 10.230.x.x? But it will just be the address my ISP has which is not visible outside right? – Siddharth Venu – 2016-08-13T15:17:03.610

Yes, that's carrier grade NAT... done wrong. The shared IP address should be in 100.64.0.0/10, and IPv6 should have been deployed before CGNAT. My site http://myip.addr.space/ can tell you if you have IPv6 connectivity.

– Michael Hampton – 2016-08-13T18:32:20.560

There is a protocol called STUN that can be used to connect two computers both behind NAT, using a service outside the NAT. – pjc50 – 2016-08-13T21:36:41.667

4"What is my actual IP address?" Private IP addresses are actual IP addresses. The only difference between private and public IP addresses is that the ISP have agreed to not route traffic with private IP addresses. Other than that, private and public IP addresses are exactly the same, and they work the same way. You happen to have private addresses on both your WAN and LAN. The ISP has the public IP address which is used to reach you on the public Internet; you don't have a public IP address. – Ron Maupin – 2016-08-14T03:24:59.107

1@SiddharthVenu: They're all your actual IP ;) – Lightness Races with Monica – 2016-08-14T14:12:02.080

@RonMaupin: "the ISP have agreed to not route traffic with private IP addresses" .... and so has your router manufacturer. – Lightness Races with Monica – 2016-08-14T20:51:19.160

@LightnessRacesinOrbit, not at all. Where did you get such a crazy idea. Routers don't care if the addresses are private or public. I could set up my router to have private addresses on all the interfaces, and it will happily route between the private networks. CGN, which the carriers are now rolling out to residential customers, wouldn't work unless routers could route between private addresses. – Ron Maupin – 2016-08-14T21:44:59.217

@MichaelHampton All the major US ISPs that are doing CGN are using 10.x addresses. While the spec sets aside the block you listed for CGN, there's no requirement to use it. It may be a bad idea for them because they will cause routing trouble for any customer that had chosen the same block as they did, but they're doing it anyway. – Moshe Katz – 2016-08-15T17:47:43.533

@MosheKatz All the major US ISPs, eh? I see proper RFC6598 addresses on Comcast. – Michael Hampton – 2016-08-15T17:52:03.283

@MichaelHampton That must either be a recent change or depend on what part of the country you are in, because I've gotten 10.x from Comcast in the past. I haven't checked recently on Comcast. I can tell you that as of today, both AT&T (wired and wireless) and T-Mobile are using 10.x addresses – Moshe Katz – 2016-08-15T17:57:20.473

@MosheKatz I'm not too surprised that some providers have done that. But saying that they all do, doesn't seem accurate. – Michael Hampton – 2016-08-15T17:58:31.677

I can't edit it anymore, so pretend it now says "As of when I last checked, all major ...". – Moshe Katz – 2016-08-15T17:59:43.130

Answers

Your internet provider is using Carrier grade NAT. Your local (to your house) IP address is 192.168.x.x. Your local (to your ISP) address is 10.230.x.x. The public, routable IP which you are sharing with many other customers of your ISP is 49.207.x.x.

user4556274

Posted 2016-08-13T15:09:11.727

Reputation: 1 274

1So to other computers, what IP should I use in my program so that they can connect to my computer? – Siddharth Venu – 2016-08-13T15:18:09.037

22@SiddharthVenu -- you can't. Your ISP (Beam Telecom Pvt?) is not providing you full internet access; carrier-grade NAT implies you have outbound access only. If your ISP provides IPv6 as well as IPv4 transport, it is likely that your IPv6 address is public. You can also host your public content with a hosting service that provides full IP connectivity rather than on your home machine(s). (Of course, if by "other computer" you mean another computer in your home LAN, then you can just connect with the local 192.168.x.x address.) – user4556274 – 2016-08-13T15:21:56.473

1Thanks for answering :) I guess I have to use VPN then... – Siddharth Venu – 2016-08-13T15:23:51.487

2@SiddharthVenu Call up your ISP and ask if they support IPv6, perhaps. – user253751 – 2016-08-14T01:48:00.827

@SiddharthVenu You can have a server without VPN or open port. See https://superuser.com/questions/121435/is-it-possible-to-host-a-web-server-from-behind-a-nat#answer-1113335.

– v7d8dpo4 – 2016-08-14T04:18:39.747

2Probably good idea will be to call ISP and ask if they sell so called "white" IPs to customers. These white IPs are routable through Internet, but usually come at a higher cost compared to "gray", carrier grade NAT IPs. – Neurotransmitter – 2016-08-14T18:37:57.267

-2

You are assigned a local IP for your internal network, and a public IP for the internet, if you type into google "what is my ip" it will return your public IP address and when you go to cmd and type "ipconfig" it will show a IPv4 address, that is your internal/local IP.

Local IPs tend to be something like:

10.x.x.x,

172.16.x.x

192.168.x.x

One of the reasons you need a local IP is due to something called NAT or Network address translation.

Further Reading: https://en.wikipedia.org/wiki/Private_network

Scripton

Posted 2016-08-13T15:09:11.727

Reputation: 47

My 172.31.x.x address is just as "local" as your 172.16.x.x address. Further reading: IETF BCP 5 (currently RFC 1918) section 3: private address space

– TOOGAM – 2016-08-14T13:46:43.780

1This answer is overly simplistic, as evidenced by the fact that it is actually wrong in the OP's case. – Lightness Races with Monica – 2016-08-14T14:10:35.250

-7

You can connect two computers in your house to each other via the 192.168.x.x IPs. To have the outside world connect to your PC is something your ISP / Cable company is trying to prevent; for instance generally the ISP will not forward port 25 for incoming mail.
They will sell you a fixed IP that you can use to have Internet access TO your PC, but you will need a server security hardened to handle everything that comes in, including various attacks that happen when you connect to the Internet, as you will be a live site, accessible to anyone. This means firewalls need to be set up correctly, etc.
So, for the average cable user, the answer is "you can't".

Engineer

Posted 2016-08-13T15:09:11.727

Reputation: 221

6It's not because "the internet is dangerous". It is because they have more customers than IP addresses to give out. – Lightness Races with Monica – 2016-08-14T14:10:55.547

5And this "you will need a server to handle everything that comes in, including various attacks" just doesn't make any sense – Lightness Races with Monica – 2016-08-14T14:11:18.390

3This is simply a money saving technique... you'll find many ISPs do still give out individual IPs. – AStopher – 2016-08-14T21:52:45.977

Tried to make my answer better by adding more info. Apparently, I was too vague for LRO. – Engineer – 2016-08-22T19:32:39.303