Would there be multiple people who share the same IP address as you?

Question

I'm not tech savvy so please bare with me. If you have a family wouldn't the whole family use the same ip address if they share the same network or wifi? Also wouldn't your neighbors also share the same ip address as you because they live close to you?

What about if you go to a school and use their computer or connect to their wifi would the whole school have the same ip address?

Answer 1

Before talking about IP addresses, we have to talk about networks.



When you log onto wifi, that's a local network, such as inside your house, or inside your school or office.



On the local network, each device (computer, phone, tablet, TV, etc.) must have a unique IP address. If 2 devices have the same IP address, bad things happen. Fortunately, most devices support a system called DHCP, which allows your wifi router to assign an IP address to a device, and prevents this problem. Yes it's possible to specify an IP address manually, but come on, what is this? 1990? Everyone just uses DHCP.



While most devices just have 1 IP address, your router has 2. One address is on your local network, and the other is on the internet. The router uses a system called Network Address Translation, or NAT, to keep track of what devices on the local network are making requests to the internet, and then directs responses from the internet to the correct device. In other words, it "routes" the traffic back and forth.



As far as the rest of the internet is concerned, "your" IP address is the IP address of your router. It is impossible to get the IP address of your device on your local network because the internet can only see your router - nothing behind it. Even if the internet knew the address of your device on your local network, it would be worthless because private network IP addresses are ignored by the internet. (they're non-routable.) In fact, it's quite possible that thousands of other computers around the world have the exact same private network IP address as you do right now - but since they're each on their own private network behind their own routers, you can't see theirs, just like they can't see yours.



It's actually possible to have multiple private networks. For instance my router's IP address facing "the internet" is another private IP address, because my ISP runs a private network for all its customers in my area, which then goes into a router which then goes out to the internet. So it sort of looks like this:



(my private home network)--[my router]--(ISP metropolitan network)---[ISP router]---(internet)



So when you look at "my IP address" you're getting the public internet IP address of my ISP's router, which is shared among thousands of other customers' routers, providing private networks to tens of thousands of individual devices.

Answer 2

Depends on which level.

First of all, it's computers that get IP addresses, not people. And one (physical) computer may even have multiple IP addresses.



Then, the only thing that is constant is that in each network segment that is administered by one router, IP addresses are unique. But only there. Take, for example, a simple home network. Everyone connected to that network, inside that network, has a different local IP. However, the router, which all those people share, only presents one IP to the outside world.

With IPv4, this scheme may or may not be repeated a few more times, with IPv6, basically every button on your shirt may have its own (world-wide) unique IP.



As for larger installations (like your workplace or school): the outside world may see one or multiple IP addresses - but even if, the association between the IP address and the physical machine may change every time you log into that network. Which is usually why the administrators of these networks log which physical machine (and which user ID) has been using which IP address at which time, so that in the case someone is doing something they shouldn't on that network, it's trivial to find the culprit.

Answer 3

Schools and companies also use NAT to multiplex the private IP space to public space, since there are very few uses that rely on a inbound connection.



I've also been on server farms where they NAT outbound connections, because there are very few outbound uses (things like smtp or software upgrades would be NATed.) This is so they can track usage, or configure ip based ACLs so they only have to register one IP instead of many.



Schools and companies would also keep a log file to indicate which IP and port corresponds with each outbound connection.

Answer 4

Routers use something called NAT or Network Address Translation to share one public IP address. Everyone in your house has the same public address. In side your house, everyone has a different IP address, one of the three designated private IP addresses.

Answer 5

SInce there are far more connected devices in the world than there are IP v4 addresses, most firewalls and home WIFI routers use port address translation to use one public IP address for all internet traffic. I've worked on a corporate network with thousands of users, and the internet saw them as one IP Address



Devices on an internal network use "private" IP addresses that by that have no routes on the internet. The most common private IP's start with 10. or 192.168. . The default address block used by most personal / Home networks is 192.168.0.0. There are millions of devices that have the IP address of 192.168.0.2, since that address will not route over the internet, they never conflict. To reach anything on another network ( to travel internetwork), any traffic from an internal network must be translated to a valid external network address.



Most of the time everyone on a home network uses the same external publicIP Address. It's possible for ISP''s to do the same thing on a larger scale if they do not have enough registered public IP's to provide one to each customer, so it's possible that if your neighbor has the same ISP, you may have the same public IP address, but that is not always the case.

Answer 6

a single ROUTER gets a SINGLE IP address(the PUBLIC IP which connects to your ISP or via a VPN). on the Other side of the router(the LOCAL connections for each connected device) each device gets its own unique LOCAL IP address. so YES externally the world just sees YOUR Router as ONE IP address but each device only gets the data that belongs to its local IP.