How to use the IP Address Validator
1. Enter one IP address per line in the left panel — IPv4, IPv6, and CIDR notation are all supported.
2. Validation runs instantly — each address shows as valid (green) or invalid (red).
3. Valid addresses show their type (IPv4/IPv6) and whether they are public, private, or loopback.
What is it?
IP address validation is essential when processing user input, parsing logs, configuring firewalls/network rules, or validating configuration files. This tool validates both IPv4 (e.g., 192.168.1.1) and IPv6 (e.g., ::1, 2001:db8::1) addresses, as well as CIDR notation for subnets (e.g., 10.0.0.0/8).
Beyond just valid/invalid, each address is classified into ranges: public (globally routable), private (RFC 1918 internal networks), loopback (localhost), or reserved. This classification is useful when auditing infrastructure configurations, filtering log entries, or building network tools.
Example
192.168.1.1 10.0.0.0/8 ::1 256.0.0.1 2001:db8::1
✓ 192.168.1.1 IPv4 · Private (RFC 1918) ✓ 10.0.0.0/8 IPv4 CIDR · Private range ✓ ::1 IPv6 · Loopback (localhost) ✗ 256.0.0.1 Invalid (octet > 255) ✓ 2001:db8::1 IPv6 · Documentation range
Validates IPv4, IPv6, and CIDR notation. Great for auditing firewall rules and cloud security group entries.
Benefits
Confirm whether an IP is IPv4 or IPv6 before routing logic
Your code may handle IPv4 and IPv6 differently — know exactly which you're dealing with before writing conditional logic.
Detect private, loopback, and link-local ranges
Identify whether an IP is publicly routable or an internal address — essential for firewall rules and access control decisions.
Validate IP input from forms before storing
Catch typos and invalid IP addresses at the point of entry rather than discovering corrupt data later in your database.
Debug ACL and firewall rules
Verify the IP you're allowing or blocking is valid and in the expected range before applying a rule to your network configuration.
Frequently asked questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation like 192.168.1.0/24 represents a network range. The number after the slash is the prefix length — /24 means the first 24 bits are the network address, leaving 8 bits for host addresses (256 IPs). Used in firewall rules, routing tables, and cloud security groups.
What are private IP ranges?
The three private IPv4 ranges are: 10.0.0.0/8 (Class A, ~16M addresses), 172.16.0.0/12 (Class B, ~1M addresses), and 192.168.0.0/16 (Class C, ~65K addresses). These are used for internal networks and are not routable on the public internet.
What is the difference between IPv4 and IPv6?
IPv4 uses 32-bit addresses (4 octets, like 192.168.1.1) with ~4.3 billion possible addresses — a space that's nearly exhausted. IPv6 uses 128-bit addresses (8 groups of hex, like 2001:db8::1) with virtually unlimited addresses. The internet is gradually transitioning to IPv6.