Public and private IP addresses solve different problems. A public IP address identifies a connection on the internet. A private IP address identifies a device inside a local network, such as a home Wi-Fi network, office LAN, school network, or internal cloud environment.
Common Private IP Ranges
Private IPv4 addresses are reserved ranges that do not route directly across the public internet. The most common ranges are 10.0.0.0 to 10.255.255.255, 172.16.0.0 to 172.31.255.255, and 192.168.0.0 to 192.168.255.255. If your computer shows an address like 192.168.1.25, that is almost certainly a private local address.
Why Routers Use Both
A router lets many local devices share one public internet connection. Your laptop, phone, printer, and smart TV can each have separate private addresses, while the router communicates externally using the public address provided by your ISP. This process is usually handled through Network Address Translation, or NAT.
NAT is one reason your private IP is not enough for a website to identify you. Websites generally see the public IP of the network path, not the internal address assigned to your device by your router.
Which One Should You Check?
If you are testing a VPN, checking your ISP, diagnosing region-based access, or confirming how websites see your connection, you need your public IP. If you are configuring a printer, router port forwarding, firewall rule, or local server, you usually need the private IP of the device inside your network.
Why the Difference Matters
Confusing public and private IP addresses can lead to failed troubleshooting. A friend cannot connect to your game server using your laptop’s private 192.168 address from another city. A router rule will not work if it forwards traffic to the wrong internal device. A VPN test will not tell you much if you only look at the address shown in your operating system network settings.