Guides/Public vs private IP addresses
Public vs private IP addresses
Most home and mobile devices use two kinds of IP addresses at once: a private address on your local network, and a public address that the rest of the internet sees. Mixing them up is one of the most common sources of confusion when people ask “what is my IP?” This guide explains both, how NAT ties them together, and which tools on getwhatismy.com show which address.
What a private IP is for
Private (local) IP addresses are assigned inside your home, office, or mobile hotspot—examples include 192.168.x.x, 10.x.x.x, and some 172.16–172.31 ranges. Your router uses them so laptops, phones, and smart devices can talk to each other without each device needing a unique address on the public internet.
Private addresses are not meant to be reachable from random websites. That is why a local IP tool often needs WebRTC or your router’s admin page: the public internet never sees those numbers. If you paste a 192.168 address into a cloud firewall allowlist, nothing useful will happen—the cloud never routes to your LAN.
What a public IP is for
Your public IP is assigned by your internet service provider (ISP). When you open a website, the site’s servers see that public address (or the exit address of a VPN or proxy). It is the identifier used for routing replies back to your network, and it is what getwhatismy.com reports on the home and IP tools.
Many households share one public IPv4 address through network address translation (NAT): every device has its own private IP, but they appear as a single public address to the outside world. Mobile carriers often use carrier-grade NAT, so thousands of phones may share a small pool of public addresses.
How NAT connects the two
NAT is the translator in the middle. Your laptop sends a packet with a private source address; the router rewrites it to the public IP and remembers which internal device started the conversation so replies can be delivered back. From the website’s point of view, only the public IP exists.
Port forwarding and UPnP exist because NAT hides devices by default. Opening a port maps a public port to a private device—useful for games and cameras, risky if misconfigured. Understanding public vs private IP is the first step before changing those settings.
Why the distinction matters in practice
Security guides, gaming, remote desktop, and cloud firewalls all depend on knowing which address you are looking at. Sharing your public IP can reveal approximate location and ISP details—useful for troubleshooting, but worth treating carefully. Sharing your private IP with someone on another network usually does nothing; sharing it on the same Wi‑Fi can help file sharing or printer setup.
If you need both views, use the [public IP tools](/) for what websites see, and the local IP tool for what your LAN uses when the browser exposes it.
Quick checklist
Ask: “Who needs to reach me?” If the answer is “a website or a friend on the internet,” you need the public IP. If the answer is “another device on my Wi‑Fi,” you need the private IP. If a VPN is on, the public IP you see is usually the VPN exit—not your home ISP—until you disconnect and recheck.