How are IPs assigned? Are all IPs unique in the world?

Answer 1

IP addresses are assigned to major internet providers, who parcel them out to smaller providers, who do the same.

In principle, numbers are unique, because when you go to a web site, it translates to an IP address, and there better only be one of them.

In practice, there are small local networks everywhere that use the same IP adresses, but they do not connect to each other, and do not get in each other's way.

For example, if you have a router in your house with a couple of computers, they probably have an address something like 192.168.1.100. Well, so does your next door neighbor, and so do I. But nobody sees the IP addresses of your computers, becaue the router has a different IP address, assigned by your ISP.

Answer 2

Well, every device connected to the internet must have a unique IP, it's true. And they're assigned one of two ways: static or dynamic. But there's also a useful trick that lets multiple computers share a single IP address ... and that trick is called a router.

Static IP addresses are exactly that: static or unchanging. They are assigned by your network administrator or ISP, and yes, you do have to configure the computer or other internet device manually to respond to that specific address.

But, as you point out, most folks don't need to do that. So how do they get their IP addresses?

Enter the dynamic IP address and "DHCP" or Dynamic Host Configuration Protocol.

Using DHCP (which is the default for Windows TCP/IP connections) the computer broadcasts a special request for an IP address to the network. An upstream device, commonly belonging to your ISP, responds with an IP address that the computer then configures itself to use. Especially when many computers aren't connected continuously, this allows the ISP to reuse the IP addresses of computers that have disconnected from the internet.

If you need your computer to be identifiable on the internet ... for example if you're running a web server or want people to be able to connect to your machine, you'll probably need or use a static IP address. On the other hand, if all you do is connect out to surf or read email, as most users do, then a dynamic IP address is the easiest to configure.

Routers are devices that allow multiple computers to "share" a single IP address. The device that's connected to the internet is the router, and it has a unique IP address. The router can then act as the DHCP server to the local network handing out local IP addresses to the computers connected to it. As traffic flows across the router, it does the job of translating the IP addresses from the local addresses it has assigned, to the external IP address it was assigned, and routing the right bits of data to the right computer ... hence the name.

One of the many side effects of using a router is that it can be assigned a static address on the internet, and hand out dynamic IP addresses locally, vice versa, or any combination.

Answer 3

IP address allocations are controlled at the highest level by the IANA. The IANA in turn issues blocks of Public IP addresses to major ISPs and so on. From your ISP a public IP address can be issued statically (meaning you use the same IP address as long as you keep that ISP) or Dynamically via DHCP (meaning your IP address can change day to day). Private IP addresses are allocated locally. You can allocate your own private IP addresses if you own a router or any other device that is capable of NAT (network address translation). NAT allows you to configure thousands of private IP addresses to a much smaller number of public or IANA routable IP addresses.

For an IP address to be routable and thereby allow you to have Internet access that IP address must be unique.

Currently the majority of public IP addresses are in the IPv4 format. The standard four octet type, such as 206.85.92.2.
The Internet is running out of IP addresses at an alarming rate due to the fact that IPv4 has a relatively low number of possible IP addresses that can be public. IPv6 is the new standard that is being implemented to solve this issue.

Answer 4

All public IP address are unique.. But anyone can use a Private IP address, for a private IP address can not be routed through the internet.

Private IP addresses can be any 10.x.x.x, 172.16.x.x - 172.32.x.x or 192.168.x.x

So, your public IP address is given to you by your ISP (this would be the IP address that you see at your router / modem) While the IP addresses inside your network would have private IP addresses.
This system is used for a number of reasons, but the two main ones would be to use public IP addresses more efficently, and to give layer of security to your internal network.

Answer 5

to be routable on the internet they have to be unique. Private NAT LANs have to be unique within them selves but you can have 2 different LANs with the same subnet / IPS because they are private and don't get routed outside the router

Answer 6

yes all IP addresses are unique,

Answer 7

IPs are like a phone number. if you dont have one you can be reached or reach out.

Answer 8

either automatically by the server or u do it manually. at least in one network, IP's have to be unique

Answer 9

the answer to your question can best be answered in the link attached.

IPs are not unique in the world they are unique within a network of computers though.