Private IP & Bogon Address Checker
Private IP & Bogon Address Checker: Checks IP against RFC 1918 private, RFC 5735 loopback, and IANA full bogon prefix tables.
About this private ip & bogon address checker
Private IP & Bogon Address Checker — browser-based utility.
How this tool works
Checks one IPv4 address against a fixed bundled subset of sixteen private, loopback, link-local, documentation, shared, benchmarking, multicast, reserved, and broadcast ranges. It does not support IPv6, fetch current IANA registries, or identify every unallocated network.
- Binary Bitmask Ingestion: Converts decimal dotted-quad IPv4 strings or hexadecimal colon-separated IPv6 strings into binary bit vectors.
- Bitwise Boolean Algebra: Performs bitwise AND, OR, and NOT operations between IP address integers and CIDR prefix masks.
- Address Class & Scope Tagging: Identifies RFC 1918 private ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16), loopback, CGNAT, and multicast blocks.
- Subnet Topology Formatting: Renders network ID, usable host range, broadcast address, binary representation, and Cisco wildcard mask.
Worked example
Scenario: Classify a documentation IPv4 address using the bundled tests.
Sample input:
Processing: Split four numeric parts and compare the 32-bit value with the fixed CIDR tests.
Illustrative output:
Limits and verification
Enforces strict IPv4 prefix boundaries (/0 to /32) and IPv6 boundaries (/0 to /128). In RFC 3021 /31 subnets, correctly reports 2 usable point-to-point hosts without traditional network and broadcast exclusions.
Examples demonstrate an expected workflow; they do not prove every input or every branch of an external specification. Check important results with an independent source before using them for money, security, compliance, safety, or irreversible file changes.
Browser processing boundary
Tool input is processed by code running in the browser and is not intentionally sent to a CZOA processing API. The page can still request ordinary site assets, analytics, or advertising when those services are enabled. Browser extensions and managed-device software remain outside this tool's control.
Relevant references
These references govern or help explain the format, protocol, or calculation used here. Listing a reference does not claim certification or complete implementation of every optional feature.
- RFC 791 (Internet Protocol: IPv4)
- RFC 4632 (Classless Inter-domain Routing: CIDR)
- RFC 4291 (IP Version 6 Addressing Architecture)
Content owner: CZOA Tools · Last reviewed: 2026-09-15 · Review methodology
How to use it
- Enter, paste, or select your input data into the Private IP & Bogon Address Checker workspace controls.
- Review available parameter fields, units, formats, or options configured for your task.
- Click the action button or observe immediate live calculations rendered in your browser runtime.
- Inspect the resulting output and any diagnostic messages, then copy or download the result if needed.
Frequently asked questions
How does the checker classify an address?+
The checker trims the text, splits it on dots, converts each of four parts with JavaScript Number, and compares the resulting 32-bit value with sixteen fixed IPv4 CIDR tests. It has no registry download and does not classify IPv6 or all unallocated addresses.
Which controls and result fields exist?+
The page provides one text input plus Run locally and Load sample. A result is JSON with input, bogon and range; malformed input also has reason. It has no WHOIS, ASN, reputation lookup, route probe, registry refresh or firewall action.
Which validation limits actually apply?+
A result is invalid only when splitting does not yield four Number values that are integers from 0 through 255. Therefore this is not a canonical IPv4 validator: JavaScript numeric coercion can accept whitespace or an empty middle part as zero. bogon false means only that none of the fixed tests matched.
What did the isolated browser classification show?+
For independently entered 192.0.2.1, the isolated browser returned bogon true and Documentation TEST-NET-1 (RFC 5737). Network requests observed during the example contained no submitted test value. This covers that fixed-table classification path only, not reachability or privacy in every environment.