IP Address Validator
Validate IPv4 and IPv6 addresses with optional CIDR notation. One address per line.
Enter IP addresses above to validate them
IP address types: what the numbers mean for networking and security
IP addresses are more than just numbers: their ranges encode important meaning about where they can be used. A developer looking at 192.168.0.1 in a network log knows immediately it is a private address from a LAN, not a source on the public internet. 127.0.0.1 means the request came from the same machine. 169.254.x.x means the client failed to get a DHCP lease. These patterns come up constantly in server logs, firewall rules, and network diagnostics.
IPv6 adds complexity with its compressed notation using :: to elide consecutive zero groups. 2001:db8::1 is documentation-only space; fe80::/10 addresses are link-local. Understanding which range an address falls into is essential for correctly configuring security groups, firewall rules, and application allow-lists. This validator surfaces that classification instantly so you can make decisions without consulting an RFC.
How to validate an IP address: step by step
- 1Enter an IP address
Type or paste any IPv4 address (e.g. 192.168.1.1), IPv6 address (e.g. 2001:db8::1), or CIDR notation (e.g. 10.0.0.0/8) into the input field. - 2Check validity
The validator immediately indicates whether the address is valid IPv4, valid IPv6, or invalid. It handles shorthand IPv6 notation with :: expansion correctly. - 3Read the address type
The type panel shows whether the address is Private, Public, Loopback, Multicast, Link-local, or Reserved. This is useful for network configuration and security debugging. - 4Check CIDR information
If you entered an address in CIDR notation, the tool shows the network address, broadcast address, and the number of usable host addresses in the range. - 5Validate a batch of addresses
Use the batch input tab to validate multiple IP addresses at once. Results show valid/invalid status for each address in the list.
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Frequently Asked Questions
- What makes an IPv4 address valid?
- A valid IPv4 address has exactly four octets (numbers) separated by dots, where each octet is between 0 and 255. For example, 192.168.1.1 is valid; 256.0.0.1 and 192.168.1 are not.
- What makes an IPv6 address valid?
- A valid IPv6 address has eight groups of four hexadecimal digits separated by colons. The :: shorthand can substitute one or more consecutive all-zero groups. For example, 2001:db8::1 is valid shorthand for 2001:0db8:0000:0000:0000:0000:0000:0001.
- What is a private IP address?
- Private IP addresses are reserved for use within private networks and are not routable on the public internet. IPv4 private ranges: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. These are defined in RFC 1918.
- What is a loopback address?
- Loopback addresses refer to the local machine. IPv4 loopback is 127.0.0.1 (the entire 127.0.0.0/8 range is reserved). IPv6 loopback is ::1.
- What is CIDR notation?
- CIDR (Classless Inter-Domain Routing) notation expresses an IP address and its subnet mask together as address/prefix_length: for example 192.168.1.0/24. The /24 means the first 24 bits are the network address, leaving 8 bits for host addresses (254 usable hosts).
- What is a link-local address?
- Link-local addresses are only valid on the local network segment and are not routed. IPv4 link-local is 169.254.0.0/16 (assigned automatically when DHCP fails). IPv6 link-local addresses start with fe80::/10.
- What is a multicast IP address?
- Multicast addresses are used to send packets to a group of receivers simultaneously. IPv4 multicast uses the 224.0.0.0/4 range. IPv6 multicast addresses start with ff00::/8.
- Is this tool free?
- Completely free. All validation runs in your browser: no data is sent to any server.
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