IP Netblocks Lookup: Check Who Owns an IP Range Now

Why Use IP Netblocks Owner Lookup?

• Exhaustive

  IP Netblocks Owner Lookup retrieves data from one of today’s most comprehensive IP Netblocks WHOIS Database that contains information on more than 10.6 million netblocks and tens of thousands of unique ASNs and ranges refreshed daily.

• Actionable

  Outputs from our IP netblocks lookup tool are formatted for intuitive data reporting with the most relevant ownership details readily available. The lookup reports can be easily shared with colleagues and relevant stakeholders via permanent URLs.

Frequently Asked Questions

What is an IP address?

An IP address is a numerical label used to identify a device, server, or network interface on the internet, allowing systems to send and receive traffic across networks. IP addresses can be IPv4, such as 8.8.8.8, or IPv6, which uses a longer format that supports a much larger address space (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334).

IP address vs. IP netblock vs. IP range vs. CIDR range: What are the differences?

An IP address is a single address (e.g., 8.8.8.8).

An IP range is a group of addresses between a starting and ending point. For example, the IP 8.8.8.8 belongs to the IP range 8.8.8.0 - 8.8.8.255.

An IP netblock is a specific type of IP range. It’s a registered block of addresses assigned to an organization or network (e.g., 8.8.8.0/24, which contains 8.8.8.8, is registered to Google LLC). An IP netblock’s size is always a power of 2, while an IP range can have an arbitrary size. So every netblock is technically an IP range, but not every IP range is a netblock. However, some vendors use these terms interchangeably.

A CIDR is a notation for representing a contiguous block of IP addresses using a network prefix and prefix length, such as 8.8.8.0/24.

How do I find out who “owns” an IP address?

You can find the registered organization responsible for an IP by running an IP Netblocks Lookup. Enter the IP into the lookup tool to see the registered IP range, organization name, ISP or hosting provider, ASN, and available contact details.

Keep in mind that the registered netblock owner is not always the exact person or company using a specific IP at a given moment.

What does “IP address owner” mean?

“IP address owner” usually refers to the organization listed in Internet resource registration data for the relevant IP netblock. This may be an ISP, hosting provider, cloud provider, enterprise, university, government agency, or other organization.

In practice, IP ownership, allocation, assignment, and leasing are different concepts.

• IP ownership or registered responsibility refers to the organization shown in the relevant IP registration record.
• IP allocation refers to the address space distributed by IANA or an RIR to another registry, ISP, provider, or organization for management or further distribution.
• IP assignment refers to the address space designated for use by a specific network, organization, customer, or end user.
• IP leasing is a commercial arrangement in which one party allows another to use IP addresses, which may not always change the top-level registered owner shown in public IP registration data.

How are IP addresses and IP netblocks related?

An individual IP address is part of a larger IP netblock. For example, the IP 8.8.8.8 belongs to a broader IP range. IP Netblocks Lookup helps identify that range, including its start and end addresses, Classless Inter-Domain Routing (CIDR) range, registered organization, and related network details.

Can one IP address belong to multiple netblocks?

Yes. An IP address can appear within both a broader parent allocation and a more specific assignment, reallocation, or routed range.

For example, a large block may be registered to an ISP, while a smaller range within it may be assigned or routed for a customer. IP Netblocks Lookup helps show the relevant registered range and ownership context. A separate leasing arrangement can also affect who is using the IP without necessarily changing the higher-level registration record.

What is an IP WHOIS lookup?

An IP WHOIS lookup finds ownership and registration details for a specific IP. It reveals the managing organization, contact details, country, and assigned network range. You can use this WHOIS lookup tool to perform an IP WHOIS lookup.

What is the difference between IP WHOIS Lookup and IP Netblocks Lookup?

An IP WHOIS Lookup retrieves registration details for an IP address, while an IP Netblocks Lookup returns that information as well as the broader block assignments, the start and end of the ranges to which the IP belongs, and ASN context.

The distinction is worth noting because an individual IP may be assigned, leased, or temporarily used by a customer, especially in ISP, VPN, hosting, and cloud environments. The registered netblock owner may not be the same as the current end user or lessee of the specific IP.

Can I find the exact person using an IP address?

Usually, no. Public IP registration data identifies the organization responsible for the IP range, not the specific individual using an IP. The actual user may be behind Network Address Translation (NAT), a VPN, a mobile carrier, a shared hosting environment, or a cloud platform. Identifying an individual user usually requires going through a legal process to access the provider’s logs.

Is the WHOIS owner the same as the user of the IP address?

Not necessarily. The WHOIS owner or registered organization is often the ISP, cloud provider, hosting provider, or enterprise responsible for the IP netblock. The current user of a specific IP may be a customer, tenant, employee, device, or lessee using that network.

Who owns all IP addresses?

No single organization owns all IP addresses. The global IP space is coordinated by the Internet Assigned Numbers Authority (IANA), which allocates address pools to RIRs. RIRs allocate, assign, and manage IP address blocks for ISPs, cloud providers, and hosting providers. Organizations that receive a direct allocation from an RIR to distribute further are called Local Internet Registries (LIRs), though not every ISP, cloud, or hosting provider holds a direct RIR allocation. Many obtain their address space as customers of an upstream LIR.

A simplified chain looks like this:

IANA → RIR → ISP, cloud provider, hosting provider, other organizations → assigned, routed, or leased to a customer or end user.

Why does IP netblock ownership matter for abuse reporting?

Abuse reports need to be directed to the organization responsible for the relevant network. IP Netblocks Lookup can help identify the registered netblock owner and available abuse contacts, making it easier to report malicious traffic, phishing infrastructure, spam, DDoS sources, or other suspicious activity to the right party.