Bogon IP Checker

Check whether an IP address is a bogon — private, reserved, or otherwise not allocated for use on the public internet. Live check, full reference table below.

Enter an IP address above and press Check.

A bogon (bogus IP) is an address that should never appear as a source on the public internet: private ranges reserved for local networks, addresses not yet allocated by IANA, and special-use ranges like loopback and documentation blocks. Traffic claiming to originate from a bogon is either a misconfiguration or a spoofing attempt — legitimate internet traffic never has a bogon source address.

Full bogon range reference

RangeTypeWhy it's a bogon
0.0.0.0 – 0.255.255.255this-networkRFC 1122 source-only range
10.0.0.0 – 10.255.255.255privateRFC 1918 private range
100.64.0.0 – 100.127.255.255sharedRFC 6598 carrier-grade NAT
127.0.0.0 – 127.255.255.255loopbackLoopback — never leaves the host
169.254.0.0 – 169.254.255.255link-localLink-local, one network segment only
172.16.0.0 – 172.31.255.255privateRFC 1918 private range
192.0.0.0 – 192.0.0.255reservedIETF protocol assignments
192.0.2.0 – 192.0.2.255documentationRFC 5737 documentation/example
192.88.99.0 – 192.88.99.255reservedFormerly 6to4 relay anycast
192.168.0.0 – 192.168.255.255privateRFC 1918 private range
198.18.0.0 – 198.19.255.255benchmarkingRFC 2544 network testing
198.51.100.0 – 198.51.100.255documentationRFC 5737 documentation/example
203.0.113.0 – 203.0.113.255documentationRFC 5737 documentation/example
224.0.0.0 – 239.255.255.255multicastOne-to-many delivery range
240.0.0.0 – 255.255.255.254reservedReserved for future use
255.255.255.255broadcastLimited broadcast address
::1loopbackIPv6 loopback
fc00::/7unique-localIPv6 private range
fe80::/10link-localIPv6 link-local range
ff00::/8multicastIPv6 multicast range

This table covers static IANA special-purpose and RFC 1918/5737/6598 ranges, checked instantly with no database lookup. It does not include the dynamic, frequently updated list of currently unallocated public IP space (Team Cymru's full bogon feed) — that list changes as IANA allocates new blocks to registries.

FAQ

Almost always either a misconfigured device on your own network sending from a private range it should not, or an external attacker spoofing a source address to evade filtering or amplify a DDoS reflection attack.
Not by itself — most bogon sightings are misconfiguration, not attack. But there is no legitimate reason for a bogon address to appear as the source of traffic crossing the public internet, so it always warrants a second look.
Yes — every GET /v1/ip/:ip call checks bogon status before anything else, returning bogon: true and a bogon_type reason if matched.
Loopback, RFC 1918 private ranges, link-local, multicast, and IANA-reserved blocks, for both IPv4 and IPv6. The result includes a bogon_type naming exactly which category matched.

About this tool

A bogon is an address that should never appear on the public internet: private ranges, loopback, link-local, documentation blocks and other reserved or unallocated space. This tool tells you instantly whether an address is one of them and which reserved range it belongs to.

How it works

The check compares the address against the published reserved ranges for IPv4 and IPv6 and shows the matching block together with a full reference table of those ranges, so you can see the rule that produced the answer.

What to keep in mind

The reserved list is a standards-based set, not a live view of what is routed. An address outside it is not guaranteed to be allocated or reachable; use the ASN and whois tools to see whether a public address actually has an owner.

Common uses

It is useful when sanitizing logs, validating that user-supplied addresses are routable, debugging NAT and VPN setups where a private address leaked into a public field, and configuring firewall rules that drop spoofed source addresses.

Related: ASN lookup · IP whois lookup · IP range directory · IP lookup