Look Up Any IP Address
An IP address lookup returns the registration and network data behind an IPv4 or IPv6 address: the organization that holds the netblock, its Autonomous System Number, the Regional Internet Registry that allocated it, an approximate geographic location, and whether the address belongs to a known hosting provider or VPN network.
What can you learn from an IP address lookup?
An IP address lookup does not identify a person. Registries allocate address space to organizations, not individuals, so the strongest attribution a public lookup can produce is the network operator responsible for the address and the abuse contact to report it to.
Who owns an IP address, and how do you find out?
Every publicly routable IP address is allocated by one of the five Regional Internet Registries to an organization, which may in turn assign it to a customer. Querying RDAP or WHOIS for the address returns the netblock it falls inside, the organization holding that netblock, the registration and last-changed dates, and an abuse contact address.
The five Regional Internet Registries are ARIN (North America), RIPE NCC (Europe, the Middle East and Central Asia), APNIC (Asia-Pacific), LACNIC (Latin America and the Caribbean) and AFRINIC (Africa). DNSX queries whichever registry is authoritative for the address rather than a cached copy.
What is RDAP, and how is it different from WHOIS?
RDAP, the Registration Data Access Protocol, is the structured JSON successor to WHOIS, standardized in RFC 7480 through RFC 7484. It returns the same registration data as WHOIS but with defined field names, consistent date formats, proper internationalization, HTTPS transport and standardized access controls, so a client can parse it without writing a separate scraper per registry.
RDAP is now the authoritative registration interface at all five Regional Internet Registries. WHOIS output remains available at most of them for compatibility, but it is free-form text with no guaranteed schema and is being retired.
How accurate is IP geolocation?
IP geolocation is roughly 99% accurate at country level. At city level it places an address within 25 miles about 81% of the time in the United States and Western Europe, and closer to 55% elsewhere. Those figures apply to fixed broadband; mobile, satellite, VPN and carrier-NAT addresses are substantially less accurate.
IP geolocation is derived from registry allocations, BGP routing data and network latency measurement, not from GPS. It locates a network interconnection point, not a device, and it cannot resolve a street address or identify an individual.
What do the IP lookup fields mean?
IP Geolocation
Maps an IP address to a physical location using databases that correlate IP ranges with geographic data from RIRs, ISPs, and crowdsourced measurements.
ASN (Autonomous System)
Identifies the network operator responsible for a block of IP addresses. Each AS is assigned a unique number and exchanges routes via BGP.
IPv4 vs IPv6
IPv4 uses 32-bit addresses (4.3 billion total), while IPv6 uses 128-bit addresses for a virtually unlimited supply. Both are actively used on the modern internet.
RDAP Registration
RDAP is the modern replacement for WHOIS, providing structured registration data including the network range, organization, abuse contacts, and registration dates.
Privacy Detection
Identifies whether an IP address is associated with a VPN, proxy server, Tor exit node, relay, or hosting/datacenter provider, useful for fraud prevention and security.
Reverse DNS (PTR)
Resolves an IP address back to a hostname via PTR records. Often used to verify mail server identity and for network diagnostics.