How IP Addresses Work
Public vs. Private IP Addresses Explained
Most devices carry two IP addresses at once: a private one for the local network and a public one for the wider internet. Confusing them causes a surprising amount of trouble.
Private IP addresses
A private IP address identifies a device inside a local network — your home, office, or phone's hotspot. These addresses come from ranges reserved specifically for private use:
10.0.0.0–10.255.255.255172.16.0.0–172.31.255.255192.168.0.0–192.168.255.255
Private addresses are not unique across the internet. Millions of home routers hand out 192.168.1.1 at the same time, and that is fine, because these addresses never travel beyond their local network.
Public IP addresses
A public IP address is globally unique and assigned by your ISP. It is the address the rest of the internet uses to reach your network. When you visit a website, the site sees your public IP — not your device's private one.
How one public IP serves a whole house
Your home might have a laptop, three phones, a TV, and a game console online at once, but usually just one public IP address. Your router performs Network Address Translation (NAT): it keeps a table matching internal devices to outgoing connections, so replies come back to the right device even though they all share one public address.
How to find each one
- Public IP: visit a tool like IP Ducky, which reports what the internet sees.
- Private IP: check your device's network settings, or your router's admin page, which lists connected devices.
Why the difference matters
The distinction explains a lot of everyday networking. Port forwarding, remote access, and gaming setups all depend on understanding that your public IP belongs to your router, while each device behind it has a separate private address. Get the two straight and home networking suddenly makes far more sense.