# IP Address Validator
Validate a list of IPv4/IPv6 addresses, get the RFC 5952 canonical form, the type (private, loopback, multicast…) and why anything failed. Runs in your browser.
## Run it
- **CLI:** `gizza tool ip-address-validate "192.168.1.1
2001:0DB8::1
100.64.0.1
10.0.0.0/8
[2001:db8::1]:443
192.168.1.256"`
- **Web:** https://gizza.ai/tools/ip-address-validate/
- **Agents:** machine-readable descriptor (parameters JSON Schema) at https://gizza.ai/tools/ip-address-validate/tool.json
## Inputs
- `addresses` — IP addresses (one per line) _(field)_
- `family` — Accepted family _(field)_
- `output` — Output _(field)_
- `ipv6_form` — IPv6 canonical form _(field)_
- `allow_prefix` — Allow /prefix suffix (10.0.0.0/8) _(field)_
- `allow_port` — Allow :port suffix ([2001:db8::1]:443) _(field)_
- `allow_leading_zeros` — Allow IPv4 leading zeros, read as decimal (192.168.01.1) _(field)_
- `dedupe` — Drop duplicate addresses _(field)_
## Output
- Result (text)
## Query parameters
Open the tool pre-filled and auto-run via URL:
- `addresses` — IP addresses (one per line)
- `family` — Accepted family
- `output` — Output
- `ipv6_form` — IPv6 canonical form
- `allow_prefix` — Allow /prefix suffix (10.0.0.0/8)
- `allow_port` — Allow :port suffix ([2001:db8::1]:443)
- `allow_leading_zeros` — Allow IPv4 leading zeros, read as decimal (192.168.01.1)
- `dedupe` — Drop duplicate addresses
Example: `https://gizza.ai/tools/ip-address-validate/?addresses=192.168.1.1%0A2001%3A0DB8%3A%3A1%0A100.64.0.1%0A10.0.0.0%2F8%0A%5B2001%3Adb8%3A%3A1%5D%3A443%0A192.168.1.256&family=any&output=report&ipv6_form=compressed&allow_prefix=true&allow_port=true&allow_leading_zeros=true&dedupe=true`
---
## About this tool
Use this when you need to check whether IP addresses are syntactically valid before they go into a firewall rule, allowlist, log pipeline, DNS zone or spreadsheet. Paste one address per line and the tool reports the canonical spelling, family, category and a specific reason for any bad line.
IPv4 and IPv6 are both supported. IPv6 output defaults to the RFC 5952 compressed form, so `2001:0DB8:0000:0000:0000:0000:0000:0001` becomes `2001:db8::1`; switch to **Expanded** when you need all eight groups. Optional `/prefix`, `:port`, bracketed IPv6 authority syntax and `%zone` ids can be allowed or refused independently.
Classification is syntax-only and local: private, loopback, link-local, multicast, documentation, CGNAT/shared, unique-local, mapped IPv4, 6to4, Teredo, NAT64, benchmarking, broadcast, reserved and global addresses are labeled from their numeric ranges. Nothing is pinged, geolocated or sent over the network.
Choose **Report** for a readable audit, **Table** for CSV, **JSON** for automation, **Valid only** for a canonical list to paste elsewhere, **Invalid only** for cleanup, or **Summary** for totals by family/category. **Drop duplicates** compares canonical forms, so different IPv6 spellings of the same address collapse together.
Limits and edge cases:
- Up to 5,000 non-blank lines or 500,000 bytes per run.
- Leading-zero IPv4 octets are rejected by default because some legacy parsers treat them as octal; enable the checkbox only for decimal input you trust.
- Classification is based on address ranges, not reachability. A syntactically global address might still be blocked, unused or unrouted in the real network.
- Ports are validated as numbers in the range 0-65535 but the tool does not test whether anything is listening there.
## FAQ
Does this check whether an address is reachable?
No. It validates syntax, canonicalizes the text and classifies the address range. It never pings, opens a socket, performs DNS, geolocates, or contacts a remote service.
Why are IPv4 leading zeros rejected?
They are ambiguous. Modern decimal-only parsers may read `192.168.001.010` as `192.168.1.10`, while old C-derived parsers can interpret leading-zero octets as octal. The default rejects them; turn on **Allow IPv4 leading zeros** only when you know the source means decimal.
Can I validate CIDR prefixes and ports?
Yes. `10.0.0.0/8`, `2001:db8::/32`, `192.0.2.7:443` and `[2001:db8::1]:443` are accepted by default and checked for family-specific prefix/port bounds. Disable the prefix or port checkbox when a field must contain a bare address.
What is the difference between compressed and expanded IPv6?
Compressed is the normal RFC 5952 style: lowercase hex, no leading zeroes, and the longest zero run collapsed to `::`. Expanded writes all eight 16-bit groups with four hex digits each. Both identify the same address.
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