What is a public IP address?
Learn the difference between public and private addresses, why websites see a gateway address, and why an address can change.
Network guides
Understand what your IP results mean
Use these practical explanations to move from a number on the screen to a useful diagnosis. Each guide connects a networking concept to checks you can perform yourself.
Reviewed: September 19, 2026
CGNAT explained and tested
Recognize carrier-grade NAT, compare router and public addresses, and interpret multi-region address changes carefully.
IPv4 versus IPv6
Understand address formats, dual-stack connections, NAT, privacy addresses, and why one protocol may work when the other does not.
How to check a VPN for IP leaks
Establish a baseline, reconnect through a VPN, compare destinations, and distinguish a real leak from normal provider behavior.
How accurate is IP geolocation?
See why country results are usually stronger than city estimates and what VPNs, mobile networks, and ISP gateways change.
Run the multi-region IP check
Compare Cloudflare with twelve AWS regions over five rounds and group every distinct public address by observation source.
A practical learning path
Start with the public-IP guide if you are new to network addressing. If your router shows an address beginning with 100.64 through 100.127, continue to the CGNAT guide. If a VPN is involved, record a disconnected baseline before testing the tunnel. The IPv6 guide is useful when results differ by protocol, while the geolocation guide explains why a correct address can still show the wrong city.
These guides deliberately separate observations from conclusions. A browser can show what a service received, but it cannot prove who used an address, where a person is located, or how a provider routes every future connection.