IP Address Type Checker

Validate any IPv4 or IPv6 address and find out exactly what kind it is: public, private, loopback, link-local, CGNAT, multicast, documentation or reserved.

Try: your IP, 192.168.1.20, 100.72.10.5, 169.254.10.1, fd12:3456::1, 10.0.0.256

What this IP address checker tells you

Not every IP address is meant for the public internet. The IETF and IANA reserve dozens of blocks for special purposes: private networks, loopback, carrier-grade NAT, documentation examples, multicast and more. This tool validates the format of the address you enter and checks it against the IANA IPv4 and IPv6 Special-Purpose Address Registries, so you know immediately whether an address is public, private or something else, and which RFC defines it.

Why it matters

  • Troubleshooting: a 169.254.x.x address means your device did not get a DHCP lease. A WAN address in 100.64.0.0/10 means your ISP uses carrier-grade NAT, so port forwarding will not work.
  • Security: applications that fetch URLs should block private, loopback and link-local destinations to prevent server-side request forgery (SSRF).
  • Configuration: confirm a range is safe to use internally before assigning it to a LAN or VPN.

IPv4 and IPv6 special-purpose ranges

BlockPurposeRFCPublic?
0.0.0.0/8"This network"RFC 791No
10.0.0.0/8Private-UseRFC 1918No
100.64.0.0/10Shared Address Space (CGNAT)RFC 6598No
127.0.0.0/8LoopbackRFC 1122No
169.254.0.0/16Link-Local (APIPA)RFC 3927No
172.16.0.0/12Private-UseRFC 1918No
192.0.0.0/24IETF Protocol AssignmentsRFC 6890No
192.0.2.0/24Documentation (TEST-NET-1)RFC 5737No
192.31.196.0/24AS112-v4RFC 7535Yes
192.52.193.0/24AMTRFC 7450Yes
192.88.99.0/24Deprecated 6to4 Relay AnycastRFC 7526No
192.168.0.0/16Private-UseRFC 1918No
192.175.48.0/24Direct Delegation AS112RFC 7534Yes
198.18.0.0/15BenchmarkingRFC 2544No
198.51.100.0/24Documentation (TEST-NET-2)RFC 5737No
203.0.113.0/24Documentation (TEST-NET-3)RFC 5737No
224.0.0.0/4MulticastRFC 5771No
240.0.0.0/4Reserved (Class E)RFC 1112No
255.255.255.255/32Limited BroadcastRFC 919No
::/128Unspecified AddressRFC 4291No
::1/128LoopbackRFC 4291No
::ffff:0:0/96IPv4-Mapped IPv6RFC 4291No
64:ff9b::/96IPv4/IPv6 Translation (NAT64)RFC 6052Yes
64:ff9b:1::/48Local-Use IPv4/IPv6 TranslationRFC 8215No
100::/64Discard-OnlyRFC 6666No
2001::/32TeredoRFC 4380Yes
2001:2::/48BenchmarkingRFC 5180No
2001:db8::/32DocumentationRFC 3849No
2001:20::/28ORCHIDv2RFC 7343Yes
2002::/166to4RFC 3056No
3fff::/20DocumentationRFC 9637No
fc00::/7Unique Local (ULA)RFC 4193No
fe80::/10Link-Local UnicastRFC 4291No
ff00::/8MulticastRFC 4291No

Everything else in IPv4, and the 2000::/3 global unicast block in IPv6, is ordinary public address space allocated by the regional internet registries. Learn the difference between public and private IPs.

Common IP format mistakes

  • Numbers above 255: each IPv4 octet is a single byte, so 10.0.0.256 is invalid.
  • Leading zeros: 010.001.001.001 is ambiguous because some software reads it as octal, so modern parsers reject it.
  • Multiple :: in IPv6: the shorthand can appear only once, otherwise the address cannot be expanded unambiguously.
  • Missing octets: 192.168.1 is not a complete address, even though some tools expand it.

Frequently asked questions

Is 192.168.x.x a public IP?

No. 192.168.0.0/16 is a private range defined in RFC 1918 and is never routed on the internet.

What is the 100.64.x.x range?

Shared address space for carrier-grade NAT (RFC 6598). If your router's WAN IP is in this range, your ISP shares one public IPv4 address among many customers.

Can I use documentation addresses on my network?

Avoid it. 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24 and 2001:db8::/32 exist so that examples never collide with real networks.

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