Private / Reserved IP Checker
Check whether an IPv4 address is private, reserved, or routable on the internet.
What you provide
Result
Reserved — Private (RFC 1918)
This address falls in a reserved range (Private (RFC 1918)) and is not routable on the public internet. Routers drop it, which is why these ranges can be reused inside every private network without collision.
- Address
- 192.168.1.1
- Scope
- Private (RFC 1918)
- Routable on the internet
- No
What this cannot tell you
- Classifies by range. It does not tell you who holds a public address, or whether it is currently in use.
- Reserved does not mean safe. Anything on your own network can use these addresses, which is exactly why they matter in a security context.
- Runs entirely in your browser. Nothing is looked up, transmitted or stored.
Take this with you
How this calculation works
The address is compared against the reserved IPv4 ranges — private networks, loopback, link-local, carrier-grade NAT, documentation and multicast among them. Anything outside every reserved range is globally routable, meaning it is allocated to someone and can appear as a source or destination on the public internet. The distinction is what makes private ranges reusable: routers drop them, so every home network can use 192.168.0.0/16 without any of them colliding.
What the results mean
- Reserved
- Falls in a range set aside for a specific purpose. Not routable on the public internet.
- Globally routable
- Outside every reserved range, so allocated to someone and routable.
- Loopback
- 127.0.0.0/8. Never leaves the machine, which is why it matters when validating a URL.
- Link-local
- 169.254.0.0/16, self-assigned when DHCP fails — and 169.254.169.254 specifically, which is cloud metadata.
Common problems and fixes
- My public IP shows as reserved
- You are probably reading a local interface address rather than the one your traffic leaves from. Carrier-grade NAT at 100.64.0.0/10 also looks private and is what many mobile networks assign.
- Why does 169.254 keep appearing?
- That is link-local — the address a machine assigns itself when DHCP does not answer. Seeing it usually means a DHCP failure.
- Is a private address safer?
- Only from the public internet. Everything on your own network can reach it, and server-side request forgery attacks specifically target private addresses from the inside.
Frequently asked questions
Which ranges are private?
10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 are the classic three. Carrier-grade NAT at 100.64.0.0/10 behaves similarly and is what many mobile carriers hand out.
Why can everyone use 192.168.1.1?
Because routers on the public internet drop packets for reserved ranges, so those addresses never conflict between networks. Reuse is the entire point of reserving them.
What is 169.254.169.254?
A link-local address used by every major cloud provider for instance metadata. It is why any server-side fetcher has to block link-local addresses before making a request.
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<iframe src="https://runthetests.com/embed/private-ip-checker/" width="100%" height="560" style="border:1px solid #e5e5e5;border-radius:8px" title="Private / Reserved IP Checker" loading="lazy"></iframe>
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