IP Address Validator and Special-Range Classifier
Validate IPv4 and IPv6 syntax according to IETF standards and classify addresses against the maintained IANA Special-Purpose Address Registries (RFC 6890, RFC 1918, RFC 6598 CGNAT, RFC 4193 ULA, and RFC 4291).
Syntax Verdict: Valid IPv4 Syntax
100.64.12.34
IANA Classification
Shared Address Space (Carrier-Grade NAT / CGNAT)
Governing Standard & Block
RFC 6598 · 100.64.0.0/10
Public Internet Routability
Non-Routable (Shared (CGNAT) Scope)
Technical Explanation
Allocated for ISP Carrier-Grade NAT between subscriber customer-premises equipment (CPE) and provider core NAT gateways.
- 32-bit IPv4 dotted-decimal notation (4 octets of 8 bits each).
Maintained IANA Special-Purpose Address Registry Table
Click any CIDR block to test an address from that reserved allocation
| CIDR Prefix | Classification | RFC Standard | Scope | Global Routable |
|---|---|---|---|---|
| "This" Network / Software Source | RFC 791 / RFC 1122 | Reserved | No | |
| Private-Use Network (Class A Block) | RFC 1918 | Private | No | |
| Shared Address Space (Carrier-Grade NAT / CGNAT) | RFC 6598 | Shared (CGNAT) | No | |
| Loopback Address Block | RFC 1122 | Loopback | No | |
| Link-Local Address Block (APIPA) | RFC 3927 | Link-Local | No | |
| Private-Use Network (16 Contiguous /16 Blocks) | RFC 1918 | Private | No | |
| IETF Protocol Assignments | RFC 6890 | Reserved | No | |
| Documentation (TEST-NET-1) | RFC 5737 | Documentation | No | |
| Private-Use Network (Home & Small Office LAN) | RFC 1918 | Private | No | |
| Network Interconnect Device Benchmark Testing | RFC 2544 | Reserved | No | |
| Documentation (TEST-NET-2) | RFC 5737 | Documentation | No | |
| Documentation (TEST-NET-3) | RFC 5737 | Documentation | No | |
| IPv4 Multicast Address Space | RFC 5771 | Multicast | No | |
| Reserved for Future Use & Limited Broadcast | RFC 1112 / RFC 919 | Reserved | No | |
| IPv6 Loopback Address | RFC 4291 | Loopback | No | |
| IPv6 Unspecified Address | RFC 4291 | Reserved | No | |
| IPv4-Mapped IPv6 Address Block | RFC 4291 | Reserved | No | |
| IPv6 Documentation Prefix | RFC 3849 | Documentation | No | |
| IPv6 Unique Local Address (ULA) | RFC 4193 | Private | No | |
| IPv6 Link-Local Unicast | RFC 4291 | Link-Local | No | |
| IPv6 Multicast Address Space | RFC 4291 | Multicast | No |
Syntactic Validity vs. Global Public Routability
A common bug in application security and webhook validation is assuming that any syntactically valid IP address is safe to dial on the public internet. Simple regular expressions often fail on compressed IPv6 notations (such as ::1 or 2405:200:1601::1) and cannot distinguish a public IP from an internal loopback or cloud metadata link-local address (169.254.169.254).
This validator parses the address into its underlying 32-bit or 128-bit integer structure and matches it against all reserved CIDR blocks in the IANA IPv4 and IPv6 Special-Purpose Address Registries. Learn more in Public IP vs Private IP and What Is CGNAT?.
SSRF & Input Hardening Checklist
- Reject non-standard octets: Always require four explicit decimal octets for IPv4 so octal or shorthand integer forms cannot bypass filters.
- Check IPv4-mapped IPv6: Block ::ffff:127.0.0.1 and ::ffff:0:0/96 when preventing Server-Side Request Forgery (SSRF).
Technical Specifications & Protocol Facts
Authoritative parameters, dimensions, and IETF RFC compliance
| Parameter / Dimension | Technical Specification | Standard / Authority |
|---|---|---|
| Canonical Document Scope | IP Address Validator & Classifier — Route /ip-validator | IPAddressLookup.in Technical Reference |
| Supported Address Families | IPv4 (32-bit dotted-decimal) & IPv6 (128-bit hexadecimal) | RFC 791 / RFC 8200 / RFC 5952 |
| Authoritative Registration Protocol | Registration Data Access Protocol (RDAP) via IANA Bootstrap | RFC 7480–7484 / RFC 9224 |
| Special-Purpose Range Classification | Private LAN (RFC 1918), Shared CGNAT 100.64.0.0/10 (RFC 6598), ULA (RFC 4193) | RFC 6890 IANA Registry |
Frequently Asked Questions
Concise answers verified against IANA, APNIC, and IETF protocol standards
What is the primary purpose of IP Address Validator & Classifier?
Verify syntactic validity and inspect whether an IP is globally routable or reserved in an IANA special-purpose block. Every output on IPAddressLookup.in follows IETF RFC standards and cites primary RIR/IANA sources.
Are IP and network queries on this page logged or shared with advertisers?
No. IPAddressLookup.in operates on a strict data-minimization model with stateless query execution, short-lived caching (15 minutes max for upstream RDAP/DNS), and zero persistent user lookup history.
How often is the technical documentation on IPAddressLookup.in reviewed?
All protocol calculators, RFC citations, and Indian telecom notes are verified by the 2026-11-01 editorial and engineering review cycle.
Related Network Tools & Technical Guides
Contextual utilities and reference documentation verified for this workflow
Diagnostic & Calculation Utilities
- IPv4 Checker
Inspect the visitor IPv4 address observed by the server, octet breakdown, and RFC 1918 / RFC 6598 CGNAT status.
- IPv6 Checker
Inspect 128-bit IPv6 reachability, eight-hextet structure, compressed/expanded form, and Indian dual-stack context.
- IP Address Converter
Convert IPv4 and IPv6 addresses across canonical, expanded, decimal integer, hexadecimal, binary, and reverse ARPA forms.
- Subnet Calculator
Calculate network address, broadcast, usable host range, wildcard mask, and 32-bit binary mask for /0 to /32.
IP Validator · Canonical: https://ipaddresslookup.in/ip-validator · Reviewed: 2026-11-01
Reviewer: IPAddressLookup.in Technical Network Utility Group · Stateless Privacy · Accuracy & Data Limits