Open your home router's settings and you'll probably see an address like 192.168.1.1. But open this website, and a completely different address shows up. How are these two related, and why are they different? The short version: the first is a private address that only exists inside your home, the second is the public address of your whole connection. This guide explains the ranges, how a router translates between them, how to tell which one you are looking at, and what it means for security and port forwarding.
What is a private IP address?
A private IP address only means something inside one local network (home, office, coffee shop) and isn't reachable from outside that network. Your router assigns a private IP to every device that connects — laptop, phone, printer — so they can talk to each other and to the router. Because these addresses never appear on the public internet, millions of homes can reuse the very same ones.
Three standard ranges are reserved for private use (defined in RFC 1918):
| Range | CIDR | Addresses | Typical use |
|---|---|---|---|
10.0.0.0 to 10.255.255.255 | 10.0.0.0/8 | About 16.7 million | Large companies, some ISP equipment |
172.16.0.0 to 172.31.255.255 | 172.16.0.0/12 | About 1 million | Mid-size networks, Docker |
192.168.0.0 to 192.168.255.255 | 192.168.0.0/16 | 65,536 | Home routers (192.168.0.x, 192.168.1.x) |
A few other special ranges are easy to confuse with these. 127.0.0.0/8 is loopback (your own machine), 169.254.0.0/16 is the self-assigned fallback you see when DHCP fails, and 100.64.0.0/10 is the shared range ISPs use for CGNAT. None of them are public.
What is a public IP address?
A public IP address is what your ISP assigns to your entire home or office connection, and it's visible and reachable from anywhere on the internet. It is globally unique at any moment, and it is the address websites actually see, the one that Show-IP.ir displays and the one that location databases map to a country, ISP and rough region (what it reveals).
So how do multiple devices share one public IP?
The answer is a process called NAT (Network Address Translation). Your router rewrites the source address of every outgoing request, remembers which device sent it, and routes the reply back to the right one. A simplified example:
| Device sends from (private) | Internet sees (public) |
|---|---|
192.168.1.20:51000 (laptop) | 203.0.113.42:40001 |
192.168.1.31:51000 (phone) | 203.0.113.42:40002 |
Both devices appear as the same address with different port numbers. That's why five people in the same house can be online at once, yet the internet sees them all under one shared public IP address. NAT is also one of the reasons the internet still works despite the IPv4 address shortage — something we cover in more detail in IPv4 vs IPv6.
The flip side: an unsolicited connection from outside has no table entry, so the router drops it. To let something in — a camera, a game server — you create a rule yourself; see port forwarding.
Quick comparison
| Feature | Private IP | Public IP |
|---|---|---|
| Example | 192.168.1.20 | 203.0.113.42 |
| Visible to | Local network only | The whole internet |
| Assigned by | Your router | Your ISP |
| Uniqueness | Can repeat across different networks | Globally unique |
| Reachable from outside | No | Yes, subject to the router's firewall |
| Has a geolocation | No | Yes, approximate |
| Cost | Free | Included, or extra for a fixed one (static vs dynamic) |
How can I tell which one I'm looking at?
- Check the number. If it starts with
10.,192.168., or172.16–172.31, it is private. - Compare the router's WAN address with Show-IP.ir. Log in to your router (router login guide) and read the WAN or Internet IP. Open the homepage to see the public IP. If they match, your router has a real public address. If they differ, your provider adds another layer of NAT (CGNAT) and you do not control a public address.
- Find your device's local IP. The guides for Windows, Android and other systems show how.
Are private addresses safer?
Partly. Because outside traffic cannot start a connection to a private address, NAT works like a rough shield — but it is not a replacement for a firewall, strong Wi-Fi and router passwords, or updates. Features such as UPnP can open ports automatically, so turn them off if you do not need them. Also remember that your public IP is still visible to every site you visit, and a VPN can replace it (how to hide your IP).
Frequently asked
Is 192.168.1.1 my IP address?
It is your router's private address inside your home. The IP you show to the internet is your public one.
Can two networks use the same private IP?
Yes, and they almost always do. That is exactly what private ranges are for. Conflicts matter only when two such networks are joined, for example over a VPN.
Why does my router's WAN IP start with 100.64?
That range is reserved for carrier-grade NAT. Your ISP shares one public address among many customers, as covered in the CGNAT article.
Key takeaways
- A private IP address only matters inside your local network and isn't visible from outside.
- A public IP address is what the entire internet, including this site, actually sees.
- NAT lets multiple devices share a single public IP address and blocks unsolicited inbound connections.
- If your router's WAN IP differs from the one on Show-IP.ir, you are behind another layer of NAT.