Look up the owner, ISP, network range, geolocation, and abuse contact for any IPv4 or IPv6 address - free, instant, powered by live RDAP registry data.
IPv4 & IPv6 supported · Real-time RDAP data · No signup required
Fetching WHOIS data…
How to Use the WHOIS IP Lookup Tool
1
Enter any IP address into the input field - for example 8.8.8.8 for an IPv4 address or 2001:4860:4860::8888 for an IPv6 address.
2
Click WHOIS IP Lookup or press Enter. The tool queries live RDAP registry data from the Regional Internet Registry responsible for that IP block.
3
Review the results - owner organisation, ISP, ASN, country, network range in CIDR notation, and the registered abuse contact for the IP block.
4
Optionally expand View Raw RDAP Data at the bottom of the results to see the full machine-readable registry record for the IP network object.
Understanding the WHOIS IP Lookup Results
Organization & ISP
The company or organisation that holds the allocation for this IP address or block, as registered with the Regional Internet Registry. For cloud and hosting IPs this is typically the provider, not the end customer.
ASN (Autonomous System)
The Autonomous System Number that identifies the network under a single routing policy. ASNs are used to map major internet operators, hosting providers, and cloud platforms. Available for ARIN-allocated IPs.
Country & Geolocation
The country associated with this IP address based on RIR allocation records. Note that geolocation from registry data reflects where the IP block was allocated, which may not match the physical server location for cloud or CDN IPs.
Network Range (CIDR)
The full IP address block this IP belongs to, in CIDR notation. Shows the size of the allocation and the complete range of addresses in the same network. A /24 contains 256 IPs; a /16 contains 65,536 IPs.
Regional Registry (RIR)
The Regional Internet Registry responsible for this IP block - ARIN (North America), RIPE NCC (Europe & Middle East), APNIC (Asia-Pacific), LACNIC (Latin America), or AFRINIC (Africa). Each registry maintains its own WHOIS database.
Abuse Contact
The email address registered for reporting abuse, spam, or malicious activity originating from this IP or network block. Submitting abuse reports to this contact is the correct first step when an IP is being used for attacks or spam campaigns.
What Is a WHOIS IP Lookup?
A WHOIS IP lookup is a query that retrieves registration and ownership information for an IP address from the internet's Regional Internet Registry system. Every publicly routable IP address on the internet is allocated by one of five RIRs, each responsible for a geographic region. A WHOIS IP lookup queries these registries using the modern RDAP protocol to return the organisation, network details, and contact data associated with any given IP.
Unlike a domain WHOIS lookup - which returns registrar and ownership data for domain names - a WHOIS IP lookup focuses on the network layer: who controls the IP block, what network it belongs to, which autonomous system routes it, and what the registered abuse contact is. This makes it essential for email security, threat intelligence, and network operations.
Both IPv4 addresses (e.g. 8.8.8.8) and IPv6 addresses (e.g. 2001:4860:4860::8888) are fully supported.
ARIN
North America
RIPE NCC
Europe & Middle East
APNIC
Asia-Pacific
LACNIC
Latin America
AFRINIC
Africa
What Can You Do with WHOIS IP Lookup Data?
Investigate suspicious sendersTrace the network owner behind an unknown email sending IP appearing in your DMARC reports
Report abuse and spamFind the registered abuse contact for any IP block and submit an abuse report directly
Threat intelligenceIdentify hosting providers and ASNs used by attackers, spammers, and malicious campaigns
Email deliverability checksVerify the ISP, organisation, and network behind your sending IP before launching campaigns
Geolocation verificationConfirm the country and RIR region of an IP allocation for compliance and access-control decisions
Network infrastructure mappingMap ASNs and IP blocks belonging to a specific organisation or cloud provider
Why Do You Need a WHOIS IP Lookup?
WHOIS IP lookup data is critical across email security, threat investigation, and network operations. Here is who uses it and why.
Email Security Teams
When DMARC aggregate reports flag an unauthorised sending IP, a WHOIS IP lookup immediately reveals which ISP or hosting provider it belongs to - helping teams determine whether it is a cloud provider being abused, a residential proxy, or a bulletproof host used for spam.
SOC Analysts and Incident Responders
During incident response, WHOIS IP lookup is one of the first triage steps. Knowing the ASN, organisation, and abuse contact for a suspicious IP helps analysts quickly determine whether traffic is from a known threat actor's infrastructure or a newly provisioned attack server.
IT Administrators and MSPs
System administrators use WHOIS IP lookup to verify that outbound mail servers are registered under the correct organisation, confirm IP allocations match expected providers, and troubleshoot deliverability issues caused by shared IP blocks with poor sending reputations.
Network Engineers and Security Researchers
Network engineers use WHOIS IP lookup to map IP allocations, verify BGP route origins, and research the ownership of autonomous systems. Security researchers use it to track infrastructure clusters used in coordinated attack campaigns across multiple IP ranges.
WHOIS IP Lookup and Email Security
Every email passes through an IP address - and that IP's ownership, network history, and reputation directly affect whether your message reaches the inbox.
Identifying Unauthorised Senders
DMARC aggregate reports show every IP sending email from your domain. A WHOIS IP lookup on unrecognised IPs instantly tells you whether they belong to a known ESP, cloud provider, or something unexpected - the first step in identifying spoofing or misconfigured sending sources.
Diagnosing Blacklist Issues
If your sending IP is blacklisted, a WHOIS IP lookup reveals whether you are on a shared block with other senders. Knowing the network range and ISP helps determine if the issue is isolated to your IP or affects the entire allocation - and who to contact to resolve it.
Verifying SPF Sending Sources
SPF records authorise specific IPs to send email on behalf of your domain. A WHOIS IP lookup on IPs listed in your SPF record confirms they belong to the expected organisation - helping you catch stale entries for decommissioned services or IPs that have changed hands.
Supporting DMARC Enforcement
Before moving to a DMARC reject or quarantine policy, every legitimate sending IP must be accounted for. WHOIS IP lookup helps verify and document the ownership of each IP in DMARC reports - a critical step toward full enforcement without blocking legitimate mail.
A WHOIS IP lookup is a query that retrieves registration and ownership data for an IP address from a Regional Internet Registry. It returns the organization that owns the IP block, the ISP, ASN, network range, geolocation, and abuse contact details.
What is the difference between a WHOIS IP lookup and a WHOIS domain lookup?
A WHOIS domain lookup returns registration data for a domain name — owner, registrar, expiry date, and nameservers. A WHOIS IP lookup returns network data for an IP address — organization, ISP, ASN, CIDR block, and abuse contact. They query different databases and return different types of information.
Does WHOIS IP lookup work for IPv6 addresses?
Yes. This tool supports both IPv4 (e.g. 8.8.8.8) and IPv6 (e.g. 2001:4860:4860::8888) addresses. IPv6 WHOIS data is maintained by the same five RIRs and follows the same RDAP standard.
Can I look up a private or reserved IP address?
Private IP ranges (such as 192.168.x.x, 10.x.x.x, or 172.16–31.x.x) are reserved for internal network use and are not registered in any public WHOIS database. Lookups for these addresses will not return ownership data.
How accurate is the geolocation returned by a WHOIS IP lookup?
WHOIS IP geolocation reflects the country of IP allocation by the regional registry — not necessarily the physical server location. Cloud providers and CDNs frequently use IP blocks allocated in one country to serve traffic globally, so actual server location may differ.
How do I report abuse for an IP address?
The WHOIS IP lookup results include an abuse contact email registered with the RIR for the IP’s network block. You can use this to report spam, phishing, or other malicious activity originating from that IP to the responsible organization or ISP.
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