Find relations like ownership between hostnames and IPs

Find out which IP range the particular IP belongs to, along with ownership information by using the world’s largest constantly updated database with billions of existing records.

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1,000 free requests monthly. No credit card required.

9.1 million+IP Netblocks in total
48,000M+Ranges updated daily
65,000K+Unique ASNs

IP Netblocks product line includes


Just take an IP address, Company name, or ASN to make a quick review on the IP range that a given IP address belongs to IP netblock borders, last update, country code, organization name, abuse history, admin and tech contact information, ASN (Autonomous System Number) and more.

IP Netblocks Lookup | Whois XML API
IP Netblocks API | Whois XML API


With one API call get detailed information about the IP range a particular IP belongs to. Protect your site and your network from spam, fraud, hackers and malicious attacks. Promptly identify and block suspicious IPs before they can cause any actual damage to your network.

IP Netblocks WHOIS Database

We provide daily updated database of the registered IP Netblocks (IP ranges) with detailed ownership information regarding each range in unified and consistent JSON or CSV formats.

IP Netblocks WHOIS Database | Whois XML API

Practical usage

Useful for Cyber Forensic analysis

Threat investigation and an essential component of any network security solution. Having IPs collected from your or your clients’ firewall logs, you can identify the networks where they have come from as well as their owners.

Trace malicious actors with contact & location details for the IP netblock.

Useful for Cyber Forensic analysis

SIEM data enrichment

  • Provide IP network intelligence (ownership information, ASN, location, etc.) across a variety of SIEM, Orchestration, Automation and Threat Intelligence Platforms.

Threat Defense

  • Threat analysts can monitor all IP addresses in a netblock containing one or more known malicious IP addresses, and build network behavioral profiles of all these IP addresses over time.
  • Safeguard an internal network from DOS attacks by blocking IP netblocks that have many known malicious IP addresses.
  • Block bad actors from misusing your infrastructure.
  • Block certain netblocks based on location.
  • Look up the owners of the IP addresses which attack your website.

Threat Hunting

  • Identify hijacked netblocks more-or-less in real time by getting daily updates for changes in the entire IP Netblocks database.
  • Enterprises can use IP netblocks database to understand their network attack surfaces.
Enrich your Marketing

Enrich your Marketing

By collecting IPs from your web server’s log and supplementing them with IP Netblocks whois data, you obtain a data set from which you can deduce the structure and dynamics of your traffic. Such information can have significant marketing implications, e.g. from which networks you are visited most frequently.

Merger and Acquisitions

Having a network you can possibly be interested in extending, by purchasing neighboring netblocks or find other free blocks for purchase.

Network Filtering and DRM

Provide access to your clients via network filtering (e.g. a software license or a journal subscription), you can identify their networks from netblocks data.

Brand Protection

Monitor your brand’s trademark or copyright and notify you of infringement when they are used on fraudulent network.

Cyber-security or business research

Address various interesting scientific research problems based on the observation of the structure and dynamics of netblocks.

Indicators of Compromise Enrichment

Enrich indicators of compromise (IoCs) within Threat Intelligence Platform, SIEMs with IP netblocks WHOIS data.

Business Intelligence and Marketing

Map visitor ip addresses to organizations to gain insights and provide personalized experience to visitors.

IP Netblocks Overview | Whois XML API

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Enterprise API Packages

API access through WhoisXMLAPI can be purchased as an annual subscription. The access pricing is based on the number of queries, which is measured monthly with per-minute rate limits. The pricing structure gives predictability to business planning and solution architecture.

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