IP Address Validator

IP Address Validator checks IPv4 and IPv6 addresses and CIDR blocks for correct syntax and classifies each valid address as public, private, loopback, link-local, multicast, unspecified, documentation or reserved, using the IANA special-purpose address registries. It shows the standard compressed and expanded IPv6 forms and, for CIDR blocks, the network address, range and size.

Firewall rules, allow-lists, server configs and log analysis all depend on correctly written addresses. A single typo, leading zero or wrong prefix length can open or block the wrong range. Classifying addresses also shows at a glance which entries are private, loopback or documentation examples that shouldn’t appear in production.

1. Paste IP addresses, one per line, or choose to split on commas and spaces.
2. Leave Allow CIDR notation on to check blocks such as 10.0.0.0/8.
3. Press Validate.
4. Review each row’s result, address type and details.
5. Filter by valid IPv4, valid IPv6, invalid or duplicates if needed.
6. Copy or download the valid and invalid lists.

• Strict IPv4 parsing that rejects ambiguous leading zeros
• Full IPv6 support including :: shortening, embedded IPv4 and zone IDs
• CIDR prefix validation for IPv4 (/0–/32) and IPv6 (/0–/128)
• Network address, range and address count for CIDR blocks
• Warnings when host bits are set in a CIDR block
• Public, private, loopback, link-local, multicast, unspecified, documentation and reserved classification
• Duplicate detection using the standard address form
• Copy and Download for valid and invalid lists

• Write IPv4 addresses without leading zeros, for example 10.0.0.1.
• Use the network address in CIDR rules (192.168.1.0/24, not 192.168.1.5/24).
• Use the documentation ranges (192.0.2.0/24, 2001:db8::/32) in examples and tutorials.
• Store IPv6 addresses in their standard compressed lower-case form.
• Treat “public” as a range type only — it does not identify an owner or location.