IP address info

What this tool checks

The address is parsed in its IPv4 or IPv6 form, and the tool returns:

Forms: the compressed and the fully expanded form, and the IPv4 form of an IPv4-mapped address.
Scope: global, private, loopback, link-local, multicast, shared, documentation, benchmarking, 6to4, Teredo, NAT64, unspecified or reserved, with the block and RFC it comes from.
Reverse DNS name: the in-addr.arpa or ip6.arpa name a PTR record for the address would have.

How to read the result

IP_NOT_GLOBAL means the address cannot be reached from the public internet, for example because it is private or reserved for documentation. Such an address in a public DNS record or an SPF term is usually a mistake.

Limitations

Nothing is looked up: the tool does not say who holds the address or whether it answers.

Use it from code

API reference for IP address info

curl -i "https://api.lookproof.dev/v1/ip/info?ip=192.0.2.1"

A request without payment is answered with 402 Payment Required and the exact price. See the API reference.

Limits

Input	IP address
Deadline	2 seconds
Freshness	Computed from the input; nothing is looked up
Price	$0.002 per check

Findings this tool can report

IP addresses (1)

Info IP_NOT_GLOBAL The address is not globally routable.

Frequently asked questions

Where does the scope come from?

From IANA's IPv4 and IPv6 Special-Purpose Address Registries. The result names the block and its RFC, for example 100.64.0.0/10 from RFC 6598 for shared address space. Addresses outside those blocks are classified with Python's ipaddress module.

What is an IPv4-mapped address?

::ffff:192.0.2.1 is an IPv6 address that carries an IPv4 address, used by dual-stack software. The result shows both forms and classifies the address by its IPv4 part.

Can I enter an address with a zone such as fe80::1%eth0?

No. A zone only means something on one computer, so it is refused. Enter the address without the % part.