Public vs private IP: what is the difference?
The easiest way to avoid confusion in networking is to separate public addresses from private local ones. A public IP is internet-routable and is what outside services see. A private IP is only meaningful inside a LAN or private environment.
- Which addresses websites can actually see.
- Why your router and devices often use different address ranges.
- How NAT changes the path between private devices and the public internet.
Public addresses
A public address is reachable on the internet, at least in theory. It belongs to an ISP, host, VPN provider, business edge, or cloud service.
This is the address WhenIP shows because it is the address presented to our servers.
Private addresses
Private addresses are used inside local networks and are not globally routed on the public internet.
Common IPv4 private ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16.
Why NAT matters
Routers commonly translate many private devices to one public address using Network Address Translation.
That is why several devices in a home can browse the web while sharing one public IPv4 address.
Troubleshooting impact
If a game, camera, or server is listening on a private address, external tools cannot reach it without the right forwarding or tunnel setup.
Port results should always be interpreted against the public address actually exposed to the internet.
Can my laptop have both a private and public IP?
Yes. It can have a private LAN address and still exit to the internet through a public address.
Why do home routers use 192.168.x.x?
Because that is part of the private IPv4 address space.
Last updated: March 29, 2026