What is an IP address, and what can it reveal about you?

You open a connection-checking website and see an IP address. Switch from home Wi-Fi to mobile data and it changes. Turn on a VPN and another address appears. Your phone, browser and accounts are still the same.

That happens because an IP address describes a network connection rather than a person's identity. It helps data reach a destination and lets the response find its way back. Understanding this role makes website location checks, home routers and the effects of a VPN much easier to explain.

Why the internet needs addresses

When you open a page, your device sends a request and the server sends a response. Enormous numbers of these exchanges happen at once. Network equipment needs sender and recipient addresses to move the data along.

IP stands for Internet Protocol. An address belongs to a network interface, such as a Wi-Fi connection. One device can have several addresses, and moving to another network can change them. That is normal rather than a sign that something is broken.

The postal-address comparison is useful up to a point. An IP helps deliver data, but it does not represent a permanent apartment on the internet. Different people may share one external address, while one person may use several addresses in a day. Device, connection and person do not have a one-to-one relationship.

Why addresses look different

The two main versions you will encounter are IPv4 and IPv6.

IPv4 is usually written as four numbers separated by dots, such as 192.0.2.1. A 32-bit address gives it roughly 4.3 billion possible combinations, a limited supply for today's internet. RFC 791 describes the protocol.

IPv6 looks longer, for example 2001:db8::1. It uses 128-bit addresses and has a much larger address space. The double colon abbreviates a sequence of zeros; the unfamiliar format does not mean the address is damaged. RFC 8200 sets out IPv6's basic rules.

These are documentation examples, not settings to enter on your device. For ordinary use, addresses are usually assigned automatically and apps handle the connection details.

IPv6 has not made IPv4 disappear. They coexist, and a device can use both. Checking a single address therefore does not necessarily describe every connection that device makes.

Local and public addresses

At home, your phone, laptop and television may connect to the same router. Each needs an address inside that network. The laptop might receive 192.168.1.10 and the phone 192.168.1.11.

These private IPv4 addresses can appear in other homes too. They are intended for internal networks and are not routed directly across the public internet. RFC 1918 defines the private address ranges.

Websites usually see a different, public address. In a common home setup, the router replaces devices' local addresses with an external one and tracks where each response should go. This is NAT, short for Network Address Translation.

An address in your Wi-Fi settings can therefore differ from the address on a checking website without anything being wrong. The first describes your device inside the home network. The second is the address through which that browser request reached the internet.

IPv6 commonly works differently: devices can have their own global addresses. Having one does not automatically mean that all incoming connections are allowed. Firewall rules and network settings matter too.

Why different customers can share an address

Sharing a public IPv4 address can extend beyond the devices in one home. An internet provider may place connections from many customers behind the same external address. This is commonly called CGNAT, or carrier-grade NAT.

The 100.64.0.0/10 range is reserved as shared address space for this purpose. It is distinct from the usual private home-network ranges; RFC 6598 explains its use.

You may never notice CGNAT when browsing. It becomes relevant if you want to accept incoming connections, perhaps to a home server. Paying for a “static IP” and obtaining a public address reachable from outside are properties worth discussing separately with your provider.

A shared address also explains why an IP cannot serve as a unique customer number. A website may receive requests from different people through the same external address. Meanwhile, your own phone and laptop may appear under different addresses.

What an IP can reveal

A public address can often be associated with the provider or organisation assigned its range. Geolocation databases estimate the country or region. The city may be wrong: database information and a user's physical location do not always match. MaxMind explains these accuracy limits.

An IP does not contain a ready-made entry listing your name, phone number and exact home address. But it is not useless for tracking either. A website can associate it with visit times, accounts and other records. A provider may have records of which customer used an address at a particular time.

It helps to separate two questions: “What does the address itself reveal?” and “What other records can it be linked to?” The first answer is limited. The second depends on what additional information exists and who can access it.

Consequently, a message saying “we know your IP” does not, by itself, mean you have been hacked. A website receives a connection address so it can send a response. What else it can infer depends on the information it holds.

Dynamic and static addresses

A dynamic address is assigned from an available pool and may change. It does not have to change every time you restart your router; the provider may assign the same one again.

A static address stays assigned to a connection under the provider's terms. It can be useful for a server or remote access, but it does not inherently increase speed or strengthen encryption.

Do not confuse consistency with reachability. First identify the task, then check the service's properties: is the address public or internal, are incoming connections restricted, and does it support the IP version you need? A marketing term such as “dedicated” explains little without those details.

Automatic address assignment is sufficient for most everyday browsing, messaging and video. An extra service is useful when it solves an actual access requirement, not simply because a fixed number sounds better.

How IP, DNS and VPNs fit together

You remember a website's name rather than its numeric address. DNS helps obtain network addresses for that domain name. One domain can have several addresses, while one address can serve several websites. Cloudflare's DNS explanation describes how this lookup works.

A VPN changes the route of selected traffic. If a request travels through a VPN server, the website normally sees its exit address. Your phone's address inside the home Wi-Fi network may remain unchanged.

A new IP does not undo account sign-ins or erase cookies. An online shop still recognises the account you use. An app with location permission may also obtain your whereabouts independently of the exit address.

How to check without getting confused

Network settings show the addresses assigned to your current connection. A trusted IP-checking page shows the public address visible to that browser request. Compare like with like: IPv4 with IPv4, IPv6 with IPv6, and the same network before and after a change.

If the address changes when you enable a VPN, that is a useful check of the browser's route. If it does not, check connection status and exclusions. Avoid drawing conclusions about every app from one website: different apps can follow different routing rules.

When contacting support, describe the symptom as well: which network you are using, what fails to open and when the problem began. An IP helps investigate a connection, but rarely explains the whole situation on its own. Treat it as a network detail that becomes meaningful alongside context.

See how your IP address changes with 2Wisp: connect to the VPN and compare the address websites see before and after connecting.