What is an IP address?
- An IP address routes data back to you. It is a delivery address, not an identity.
- You have two at once: a private one inside your network, and a public one your whole household shares.
- It reliably reveals your country and your internet provider. City-level accuracy is a coin flip, and street level is not possible at all.
- Most home addresses are dynamic, so yours changes on its own schedule without you doing anything.
- Who owns your address range is public information — which is exactly how sites decide whether you look like a household or a server.
The postal analogy holds up better than most. Your public IP is the number on the front of the building. Your private IP is the flat number inside. The post office needs the first to get the parcel to the right building; the concierge needs the second to get it to the right door. Neither one tells anybody your name, and that distinction matters more than almost anything else on this page.
Where the analogy breaks is permanence. A house number stays put for a century. Your public address is usually a lease from a shared pool, and it can change while you are asleep.
Anatomy of an address
Four numbers, 0–255 each. Underneath they are just 32 bits, split into a network part and a host part.
Reserved by RFC 1918. The block almost every home router hands out.
The slash number you sometimes see written after an address — 203.0.113.0/24 — says how many of those 32 bits belong to the network. A /24 reserves 24 bits for the network and leaves 8 for hosts, which is where the familiar 254 usable addresses comes from. Providers buy and sell address space in these blocks, and subnetting is simply the act of slicing a block into smaller ones.
IPv4 vs IPv6
They are not short. They are abbreviated by two rules you can watch being applied.
2001:db8::ff00:42:8329One run of consecutive zero groups may be replaced by ::, and only one, or it would be ambiguous.
All three lines are the same address. Only the last one is what you would normally see written down.
Public, private and NAT
Private addresses are invisible to the internet. Only the address on the far right is ever recorded by a website.
- Private traffic — never leaves your network
- Translated to your public address
Your router keeps a table mapping each outgoing connection back to the device that started it. Three devices, three private addresses, one public address — and the website you visit only ever learns the last one.
Private addresses
Three ranges are reserved for internal use and are never routed across the internet. Every network on earth is free to reuse them, which is why the same address exists in millions of homes at once.
- 10.0.0.0 – 10.255.255.255
- 172.16.0.0 – 172.31.255.255
- 192.168.0.0 – 192.168.255.255
Your public address
One address, leased to your router by your provider, shared by every device in the building. This is the one a website logs, the one a geolocation database looks up, and the one a firewall bans. Everything on this page that matters for privacy concerns this address and not the private one.
Check yours with the what is my IP tool.
How you get an IP address
IANA
Holds the global pool and hands large blocks to five regional registries. It has had no free IPv4 blocks to give since 2011.
Regional registry
RIPE, ARIN, APNIC, LACNIC or AFRINIC allocate to providers in their region and publish who holds what. This public record is what makes IP classification possible.
Your provider
Leases one address from its block to your router, usually temporarily, and often shared with other subscribers behind carrier-grade NAT.
Your router
Hands out private addresses to every device in the house via DHCP, and translates them all onto the single public address.
Nothing you did caused any of these changes. That is what dynamic means.
Your provider leases you an address from a shared pool. When the lease ends or the connection drops, you may or may not get the same one back.
Hosting anything reachable from outside, running a VPN endpoint at the office, or getting onto a corporate allowlist that checks the source address. All of these break the moment your address moves.
A never-changing address is a stable identifier for anyone tracking you, and a permanent target if it ever lands on a blocklist. Dynamic addressing quietly gives you a small amount of privacy for free.
What your IP address actually reveals
Bars show roughly how often a commercial geolocation database gets it right. Tap a row for the reason.
City: Frequently resolves to the provider exchange rather than you. Being placed in a city 200 miles away is entirely normal.
Accuracy figures are indicative of typical commercial databases, not a measurement of any one provider. Check what yours currently returns with the IP lookup tool.
Why geolocation gets your city wrong
There is no lookup table that maps addresses to places. Commercial databases build their guesses from registry records, network latency measurements, and whatever a provider chooses to publish about where a block is deployed. When a provider routes an entire region through one exchange, every subscriber in that region appears to be sitting in that one city.
This is also why two lookup services disagree about you. They are not reading a fact, they are each making an inference from different evidence.
How sites classify an IP address
A site cannot see who you are, but it can see who owns your address range — and it judges accordingly.
This classification is the entire reason proxy pricing looks the way it does — see our proxy lesson for how each type is sold.
The ASN is the real signal
Every address range sits inside an autonomous system, identified by a number and registered to an organisation. Look up an address and you learn instantly whether it belongs to a national broadband provider, a mobile carrier or a cloud host. No household browses from a hosting company, so that lookup alone separates most automated traffic from most human traffic before any other check runs.
Layered on top is reputation: a running record of whether that address has recently sent spam, failed logins or scraping traffic. On a shared address you inherit whatever the previous occupant did, which is why a brand-new VPN server can be blocked on its first day.
Changing or hiding your IP address
Same goal, very different trade-offs.
Encrypts everything and moves your apparent location to the server. Simplest option for privacy from your provider and on public Wi-Fi. You are trusting the VPN company with what your provider used to see.
None of these hides you from a site you log into. The moment you sign in, the account identifies you far more precisely than an address ever could.
Just want a different address?
On a dynamic connection, unplugging the router for a few minutes often does it for free. Whether it works depends entirely on how your provider manages its pool.
Want privacy from your ISP?
A VPN is the right tool. It encrypts everything and covers the whole device, so your provider sees a tunnel and nothing about its contents.
Need many addresses at once?
That is a proxy job. VPNs give you one address at a time; proxy pools give you thousands, rotating per request if you want.
Test yourself
1Which of these is a private IP address?
2Your IP address reveals your street address.
3How many bits long is an IPv4 address?
4What does NAT do?
5Why are datacenter IPs blocked more often than residential ones?
IP address FAQ
1What is an IP address in simple terms?
It is the address that tells the internet where to send data back to. Every device that speaks to a network gets one, in the same way every house on a street needs a number for post to arrive. Without it a server would have your request but no idea where to deliver the reply.
2What does my IP address actually reveal about me?
Reliably: your country, your internet provider, and the network your traffic belongs to. Usually: your approximate region and rough city, though the city is wrong often enough that it should never be treated as fact. Never: your name, your street address, your device contents or anything you typed. IP geolocation is an educated guess built from registry records and measurement data, not a GPS fix.
3What is the difference between a public and a private IP address?
A private IP such as 192.168.1.14 only has meaning inside your own network and cannot be routed across the internet. Your router holds one public IP that the whole household shares, and translates between the two using NAT. A website only ever sees the public one.
4Does my IP address change?
Most home connections use dynamic addressing, so your public IP can change when your router reconnects, when the lease expires, or when your provider reorganises its pool. Some change daily, some hold the same address for months. Business connections often pay for a static IP that never changes.
5Is IPv6 replacing IPv4?
Slowly, and alongside rather than instead of. IPv4 ran out of free addresses in 2011 and IPv6 offers a practically unlimited supply, but the transition has taken decades. Most connections today are dual-stack, meaning they hold both and use whichever the destination supports.
6Can two devices have the same IP address?
Two devices can share the same private address as long as they are on different local networks, which is why 192.168.1.1 exists in millions of homes at once. Two devices cannot hold the same public address at the same time, though carrier-grade NAT means hundreds of subscribers can appear behind one.
7How do I hide my IP address?
Route your traffic through something else. A VPN sends everything through an encrypted tunnel so the site sees the VPN server and your provider sees only the tunnel. A proxy substitutes the address for specific applications. Tor layers three relays so no single one knows both ends. Each has a different trade-off between speed, cost and trust.
8Why do some websites block my IP address?
Because addresses carry a reputation. Ranges registered to hosting companies are flagged as datacenter traffic, and addresses that have previously sent spam or abuse are listed publicly. If you are on a VPN or a shared proxy you may inherit whatever the previous user did with that address.
9What is CGNAT and why does it matter?
Carrier-grade NAT is a second layer of translation run by your provider, so hundreds of subscribers share one public address. It conserves scarce IPv4 space, but it means you cannot host a server or forward a port, and a ban applied to that address hits everyone behind it.