An IP (Internet Protocol) address is a numeric identifier assigned to every device on a network. It's how packets find their way to and from your device β the internet's equivalent of a return address on an envelope.
IPv4 vs IPv6
Two versions in active use:
- IPv4: 32-bit addresses, written as
four numbers separated by dots (e.g.,
192.168.1.1). About 4.3 billion possible addresses. We ran out globally around 2011. - IPv6: 128-bit addresses, written as
eight groups of hexadecimal (e.g.,
2001:db8::1). Effectively unlimited address space. Adoption has been slow but is now widespread.
Most devices today have both β an IPv4 address and an IPv6 address β and use whichever is appropriate for a given connection.
Public vs private
Your device usually has two IPs:
- Private IP: assigned by your local
router (e.g.,
192.168.x.x). Only meaningful on your home/office network. - Public IP: assigned by your ISP and visible to the wider internet. This is the IP websites see when you connect.
Behind a home router, all your devices share one public IP via NAT (Network Address Translation). On mobile data, many users often share an IP via CGNAT.
What an IP reveals
- Your ISP β reverse lookup tells anyone which provider owns the IP block.
- Approximate location β geolocation databases map IPs to city/region.
- Whether you're on a VPN, datacenter, or Tor β IP intelligence services flag these.
What an IP doesn't reveal: your name, exact home address, what you're doing online. Those require additional information.
How a VPN changes your IP
When connected to a VPN, websites see the VPN server's IP instead of your real one. The VPN's IP belongs to the VPN provider, not you β so reverse lookup identifies the VPN, not you. The IP is also shared with many other VPN users, which makes individual identification harder.