About the IP Address Checker
Most IP problems in config files are typos: an octet over 255, a missing colon group, or a stray space copied from a spreadsheet. Paste a whole list here and each line is checked for structural validity, then classified — public, RFC 1918 private, loopback, link-local, carrier-grade NAT or multicast — so you can see at a glance whether an allowlist contains what you expect.
How to use the IP Address Checker
- Paste one IP address per line — IPv4 and IPv6 can be mixed.
- Read the table for each address's version and validity.
- Check the notes column for the address type.
- Fix the invalid rows using the reason given.
Why use this tool?
Bulk checking
Validate an entire allowlist or firewall rule set in one paste instead of line by line.
Range classification
Identifies 10.x, 172.16-31.x and 192.168.x private ranges, 127.x loopback, 169.254.x link-local and 224-239.x multicast.
IPv6 shorthand
Understands :: compression and rejects addresses that use it more than once.
Frequently asked questions
Is 192.168.1.1 a valid public IP?
It is a valid address but it is private, reserved by RFC 1918 for local networks. It is not routable on the public internet.
Why is 010.1.1.1 rejected?
Leading zeros are ambiguous — some systems read them as octal — so a strict validator treats them as invalid. Write 10.1.1.1.
Does this look up who owns the address?
No. It checks the format and range type only. For ownership you would need a WHOIS or RDAP lookup.