Public vs Private IP Address: What Matters
Public vs private IP address: your public IP is the address an outside service sees for your internet connection; your private IP is used inside your home, office, or hotspot. Routers translate IPv4 between these scopes, so both can be correct at once.
Public vs private IP address: the difference
A public IP address has a path across the public internet. Websites and IP-lookup tools normally see the address of the router, carrier, company gateway, VPN, or proxy sending your traffic. A private IP has meaning only within a local network, such as home Wi-Fi, and is assigned to a device by the router or another local DHCP service.
| Question | Public IP | Private IP |
|---|---|---|
| Where does it work? | Across internet-facing routes | Inside a local or managed network |
| Who normally assigns it? | ISP, mobile carrier, employer, VPN, or hosting provider | Router, DHCP server, administrator, or device configuration |
| Who can normally see it? | Remote services reached through that connection | Devices and network equipment in the local scope |
| Can unrelated networks reuse it? | Not as the same active internet route | Yes; private ranges are designed to be reused |
| What is it used for? | Identifying the outward connection | Delivering traffic to the right local device |
“Private” describes routing scope, not perfect secrecy. “Public” does not identify a person by itself: the address can be dynamic, shared by subscribers, or replaced by a VPN. A private address can still be visible to the router, local administrators, and software on the device.
How NAT connects them
On an IPv4 home network, network address translation (NAT) bridges the two scopes. When a device starts a connection, the router rewrites the source address and often the source port, then keeps a mapping so replies return to the right device. RFC 3022 describes this mapping between private and external address realms.
Worked example: a laptop at 192.168.1.24 requests a page. The router may send it as the documentation address 203.0.113.42 and remember the laptop’s port. The website sees the outward address. These are documentation examples, not live addresses.
NAT makes outbound browsing straightforward because the device starts the session. An unsolicited inbound request has no translation entry, so it cannot automatically choose a private device. Port forwarding adds a deliberate rule from a public port to a private address and service; use it only when needed and keep the target updated. Read what port forwarding does before exposing a service.
Private IPv4 ranges and special cases
RFC 1918 defines three IPv4 blocks for private networks:
10.0.0.0/8:10.0.0.0through10.255.255.255.172.16.0.0/12:172.16.0.0through172.31.255.255. Not every address beginning with 172 is private.192.168.0.0/16:192.168.0.0through192.168.255.255.
One of these values is a local IPv4 address. 127.0.0.1 is loopback, meaning “this device,” while 169.254.0.0/16 is link-local fallback space often associated with failed DHCP. Neither is a normal public address.
Do not call 100.64.0.0/10 an RFC 1918 private range. IANA labels it Shared Address Space, and RFC 6598 defines it for provider-side carrier-grade NAT. If your router’s WAN address is there, your ISP may be translating your connection again; see what CGNAT means.
IPv6 uses different scopes. A device may have a global IPv6 address and a link-local address beginning with fe80:; RFC 4291 says link-local traffic is not forwarded between links. Unique Local Addresses use fc00::/7. A global IPv6 address still needs a firewall policy.
Find your public and private IP addresses
Use two observations. First, open Loqmi’s public IP tool and record the IPv4 and IPv6 values it reports. Next, read the active interface on your device; ignore disconnected adapters, loopback, virtual machines, and VPN interfaces unless they are the path you are diagnosing.
Windows 11
Go to Start > Settings > Network & internet. Choose Wi-Fi and the connected network, or Ethernet; open Properties and read IPv4 address. The Windows Network profile setting called Public or Private controls firewall and discoverability, not IP classification.
macOS
Go to Apple menu > System Settings > Wi-Fi > Details. For wired Ethernet, use System Settings > Network > Ethernet > Details > TCP/IP. The displayed IP address is normally the Mac’s local address.
Linux
On Ubuntu’s desktop, open Activities > Settings > Network or Wi-Fi, then select the settings button beside the active connection. In most Linux terminals, run ip addr and read inet for the active interface; skip lo and inet6 for IPv4. Desktop menus vary.
Android
On Pixel-style Android, open Settings > Network & internet > Internet, tap the connected Wi-Fi network or its settings icon, and open network details. Look for IP address. Other vendors may use Settings > Connections > Wi-Fi. Private DNS and Randomized MAC address are different settings.
iPhone or iPad
Open Settings > Wi-Fi, tap the info button beside the connected network, and read IPv4 Address > IP Address. This is the private Wi-Fi address. iOS generally does not show the cellular public address in Settings, so use Loqmi in a browser while cellular data is active.
Choose the right address for the job
| Your goal | Use | Why |
|---|---|---|
| Connect a printer, TV, or file share locally | Private IP | The traffic stays inside your LAN. |
| Open your router’s administration page | Private gateway address | The gateway is local; Loqmi’s result is not the normal management address. |
| Check what a website or game server sees | Public IP | It is the address presented outside your network. |
| Set up remote access or port forwarding | Public address plus target private IP | The router must map the outside port to the intended device. |
| Ask an ISP about a fixed address | Public IPv4 or IPv6 details | Static describes stability, not routing or inbound permission. See static versus dynamic IP addresses. |
Troubleshoot a mismatch without guessing
| What you observe | Likely meaning | Next action |
|---|---|---|
| Device IP differs from Loqmi | Normal NAT | Use the device value locally and Loqmi’s value for internet-facing support. |
Router WAN is 100.64.0.0/10 | CGNAT is likely | Ask the ISP about a public IPv4, native IPv6, or another inbound option. |
Router WAN is 10/8, 172.16/12, or 192.168/16 | Upstream NAT or a second router | Check the modem-router layout before changing port-forwarding rules. |
| Router WAN looks public but differs from Loqmi | Another gateway, VPN, proxy, or provider design | Disable VPNs, check bridge/router mode, and ask the ISP. A mismatch alone is not proof of CGNAT. |
| Remote port is closed | CGNAT, stopped service, firewall, wrong protocol, or wrong target | Verify the service locally, then test from another network. |
Three shortcuts that cause bad diagnoses
“Private means secret.” It only means limited routing scope; your router, administrator, and local software can still use it. “Public means permanent and personal.” A provider can change it, a carrier can share it, and a VPN can replace it.
“A speed test tells me which IP I have.” It does not. It measures performance. Use Loqmi’s speed test as a before-and-after baseline, not as an address-scope test.
Run this quick self-test:
- On home Wi-Fi, open Loqmi on two devices and note the public IPv4. The same outward IPv4 is normal when both use one router.
- Read each device’s local address. Different private values show how the router identifies devices inside the LAN.
- Turn off Wi-Fi on a phone, or disconnect a VPN, and check Loqmi again. A different result means the internet path changed.
Key takeaways
- Public means an internet-facing routing scope; private means a limited local scope. You can use both at once.
- IPv4 NAT maps private devices to an outward address, while port forwarding creates a specific inbound path.
- Check the full range, not just the first octet:
172.16.0.0/12is private, but every 172.x.x.x address is not. 100.64.0.0/10is provider Shared Address Space, a useful CGNAT clue rather than an RFC 1918 private range.- Use Loqmi for the public result and your active adapter’s settings for the private result; choose the one that matches the task.
Frequently asked questions
Can two homes have the same private IP address?
Yes. Private IPv4 ranges are intentionally reusable, so two unrelated homes can both use 192.168.1.20 without conflict. The address is only meaningful inside each local network. A router translates each home’s local traffic before it reaches the internet, where the connection is represented by a different address or shared provider gateway.
Why does my public IP change when I switch Wi-Fi?
A public IP belongs to the connection path, not permanently to your phone or laptop. A different Wi-Fi network has a different router and provider, while cellular data uses a mobile carrier gateway. A VPN or proxy can also replace the address that websites see. Your local address will usually change as well.
Is a public IP address the same as a static IP?
No. Public describes where an address can be used and seen; static describes whether the assigned value is intended to stay the same. A public address can be dynamic and change after a lease or network event. A static address can be useful for hosting, but it still needs a firewall and an allowed inbound path.
Can a public IP expose my exact home address?
Usually not. An IP lookup can often associate the address with an ISP, organization, or approximate area, but the address may be shared, reassigned, or located at a provider gateway. Exact subscriber details are held by the provider and normally require its records and a precise time. Treat the public IP as connection information, not a street address.
Sources
- RFC 1918: Address Allocation for Private Internets
- IANA IPv4 Special-Purpose Address Registry
- RFC 3022: Traditional IP Network Address Translator
- RFC 6598: Shared Address Space
- RFC 4291: IPv6 Addressing Architecture
- Microsoft Support: Essential Network Settings and Tasks in Windows
- Apple Support: Wi-Fi settings on Mac
- Pixel Phone Help: Manage advanced network settings on your Pixel phone