Every IP address belongs to a special-use category defined by IANA: some are globally routable and can be geolocated, while others are private, loopback, link-local, or reserved and never appear on the public internet. This tool classifies any IPv4 or IPv6 address and explains what it reveals — useful when auditing logs, configuration files, screenshots, or any text that might contain IP addresses you didn’t intend to share.
How it works
The checker inspects the leading bits of the address against the IANA special-use registries:
IPv4 classifications:
| Range | Classification | What it means |
|---|---|---|
| 10.0.0.0/8 | Private (RFC 1918) | Internal network, not routable |
| 172.16.0.0/12 | Private (RFC 1918) | Internal network |
| 192.168.0.0/16 | Private (RFC 1918) | Home/office LAN |
| 127.0.0.0/8 | Loopback | Same machine only |
| 169.254.0.0/16 | Link-local (APIPA) | Auto-assigned when no DHCP; signals a config problem |
| 100.64.0.0/10 | Carrier-grade NAT | ISP-level private space (RFC 6598) |
| 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24 | Documentation (RFC 5737) | Examples only; should never appear in live traffic |
| 224.0.0.0/4 | Multicast | Routing protocols and streaming |
| 240.0.0.0/4 | Reserved | Not usable on public internet |
| Everything else | Public (globally routable) | Unique, can be geolocated |
IPv6 classifications:
| Range | Classification |
|---|---|
| ::1/128 | Loopback |
| fc00::/7 | Unique-local (RFC 4193) — equivalent to RFC 1918 private |
| fe80::/10 | Link-local — scope is a single network segment |
| ff00::/8 | Multicast |
| 2001:db8::/32 | Documentation (RFC 3849) — examples only |
| 2000::/3 | Global unicast (publicly routable) |
Privacy implications by category
Public / globally routable — The address is unique on the internet. Any organization operating the IP range can be identified via WHOIS, and an approximate geolocation (city or region level) is possible via GeoIP databases. Exposing a public IP in a screenshot, URL, config file, or public log reveals your ISP and rough location. If you see an unexpected public IP in a config, it may be a hardcoded production endpoint or a misconfiguration.
Private (RFC 1918) — The same ranges (10.x, 172.16–31.x, 192.168.x) are reused on millions of separate networks behind NAT. A private address is not unique on the internet and cannot be geolocated or contacted from outside your network. Leaking a private address reveals internal topology but not your location.
Link-local / APIPA (169.254.x.x or fe80::/10) — These addresses are auto-assigned when a host cannot reach a DHCP server. Seeing one in a running system almost always indicates a DHCP failure or misconfigured interface.
Documentation ranges — If you see 192.0.2.x, 198.51.100.x, 203.0.113.x (IPv4) or 2001:db8:: (IPv6) in live traffic, something is wrong. These are reserved for documentation examples and examples only and should never appear in production.
What the checker doesn’t do
This tool classifies addresses by the IANA range tables built into the JavaScript — it does not look up the address online. It can tell you whether an address is globally routable, but it cannot tell you which organization owns it, what hostname it resolves to, or what its current geolocation is. For those, use a WHOIS lookup or GeoIP tool after confirming the address is safe to query.