Guides
What Is an IP Address? IPv4, IPv6, Public and Private
What is an IP address and how does it work? IPv4 vs. IPv6, public vs. private, dynamic vs. static, who assigns addresses and what yours reveals.
Every device that connects to the internet needs an address so that data can reach the right place. That address is called an IP address. When you open a website, send a message or watch a video, IP addresses are what let the data find its way. This guide explains what an IP address is, how it works, the difference between IPv4 and IPv6, public versus private addresses, and what your IP address does and doesn't reveal about you.
What Is an IP Address?
IP stands for “Internet Protocol”. An IP address is a numeric label that identifies a device on a network, much like a street address in the postal system. When one device sends data to another, it splits the data into small packets and stamps each one with the sender's and the recipient's IP address. Routers along the way read that address and pass the packet on to its next stop.
People remember names better than numbers, so we reach websites through domain names such as google.com. Behind the scenes, a system called DNS translates the name into an IP address. You can see which IP address a site uses with the IP lookup tool, and the rest of a domain's records with the DNS lookup tool.
IPv4 vs. IPv6
Two versions of IP are in use side by side today:
| Feature | IPv4 | IPv6 |
|---|---|---|
| Example | 203.0.113.45 | 2001:db8:85a3::8a2e:370:7334 |
| Length | 32 bits | 128 bits |
| Notation | Four numbers (0–255) separated by dots | Eight hexadecimal groups separated by colons |
| Number of addresses | About 4.3 billion | Effectively unlimited (2128) |
IPv4 was designed in the 1980s, when 4.3 billion addresses looked like more than enough. The number of connected devices passed that figure long ago, so the pool of unused IPv4 addresses has run dry; that is why providers turn to techniques such as CGNAT, which shares one address among many subscribers. IPv6 is the long-term fix: its address space is large enough to give every device its own public address. The transition has been under way for years, so most connections use either IPv4 only or both together (dual stack). You can check whether your connection supports IPv6 with the IPv6 test.
Public vs. Private IP Addresses
Most people actually have two different IP addresses, and the two are often confused.
Your public (external) IP address is the one your internet provider assigns to your router, and the one the rest of the internet sees. Every device in your home goes online through this single address. It's the address shown on our home page.
A private (local) IP address is the one your router hands to each device on your home network, and it only means something inside that network. These addresses come from ranges reserved for private use:
192.168.0.0–192.168.255.255(most home routers)10.0.0.0–10.255.255.255172.16.0.0–172.31.255.255
Addresses in these ranges aren't routed on the internet, which is why millions of homes can use the same 192.168.1.x addresses without clashing. Your router translates between the private addresses and the public one using a technique called NAT. The router's own private address (often 192.168.1.1) is also where you log in to your router.
Dynamic vs. Static IP Addresses
On home connections the public IP address is usually dynamic: the provider lends it from a pool, and it can change when the router reconnects. A static IP never changes; it suits people who host servers or need to reach their network from outside, and it is usually a paid add-on. See our static IP guide for details.
Who Assigns IP Addresses?
IP addresses aren't picked at random; they are handed out through a hierarchy. At the top, IANA allocates large blocks to five regional internet registries (RIRs): ARIN for North America, RIPE NCC for Europe and the Middle East, APNIC for Asia-Pacific, LACNIC for Latin America and AFRINIC for Africa. The registries assign blocks to internet providers and large organizations, and your provider gives you an address from its own blocks.
Each provider's network is also identified by an ASN (autonomous system number). You can find out which organization an IP address is assigned to, and which ASN it belongs to, with the WHOIS lookup tool.
What Does Your IP Address Reveal About You?
Every site you visit sees your IP address; the connection couldn't be made otherwise. From an IP address, a site can work out:
- Your internet provider and its network's ASN.
- Your approximate location: the country is almost always right and the city usually is. On mobile connections, and with providers that use CGNAT, a different city may show up.
- The type of connection: home broadband, a mobile network, a data center, a VPN or a Tor exit node.
What your IP address doesn't reveal is your name, home address or phone number. Only your internet provider knows which subscriber held a given IP address at a given moment, and it shares that only with the authorities in response to a lawful request.
How Do I Find My IP Address?
For your public IP address, just open the ipadresimne.net home page. If you prefer the command line, this prints the address and nothing else:
curl ipadresimne.netYour private IP address is listed in your device's network settings:
- Windows: run
ipconfigin Command Prompt and look for the “IPv4 Address” line. - macOS: System Settings → Network → your connection → Details.
- Linux: run
ip addrin a terminal. - Android / iPhone: open the details of the network you're connected to in Wi-Fi settings.
Can You Hide Your IP Address?
You can't make your IP address disappear, but you can make sites see a different address instead of yours. That's what VPNs, proxies and Tor do: your traffic goes to an intermediate server first, and sites see that server's IP address. We cover how these methods differ, and the other ways to change your address, in our guide to changing your IP address. If you use a VPN, the WebRTC leak test confirms that your real address isn't leaking through your browser.