Public / Private IP Checker

Check whether an IP is private, loopback or a reserved range.

Not every IPv4 address is reachable on the internet. Some ranges are reserved for special use — private networks, loopback, link-local, documentation — and are never routed on the public internet. This tool tells you which range an IP belongs to, whether it is internet-routable, and the RFC behind it.

Use it to tell whether an IP in your server logs is an internal address or an external visitor, or while reviewing firewall and proxy settings.

IPv4 addresse.g. 10.0.0.5, 8.8.8.8, 127.0.0.1

Private IP (RFC 1918)

Classification	Private IP (RFC 1918)
Internet routable	No (special/private range)
Matched range	192.168.0.0/16
Reference	RFC 1918

Key special ranges

Private (RFC 1918): 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16 — internal only.
Loopback: 127.0.0.0/8 — the host itself (localhost).
Link-local: 169.254.0.0/16 — auto-assigned when DHCP fails (APIPA).
CGNAT: 100.64.0.0/10 — carrier shared NAT range.
Documentation: 192.0.2.0/24 and others — examples only, not routable.

Seeing 169.254.x.x?

If a device has this address, it failed to get an IP from DHCP — a common cause of "no internet" issues.

Frequently asked questions

Can a private IP be reached directly from the internet?

Not directly. It must pass through NAT on a router/firewall to a public IP. To reach an internal server from outside you need port forwarding or a VPN.

Is seeing a CGNAT range (100.64.x.x) a problem?

It means your carrier applies shared NAT due to IPv4 scarcity. Fine for general use, but it can limit hosting inbound servers or some P2P.

Does it classify IPv6?

Currently IPv4 only. IPv6 special-range classification is planned as a separate tool.