Pro move: type dmarc:yourdomain.com or blacklist:1.2.3.4 straight into the box — it switches tools for you.
About this tool. Every IP address belongs to a block allocated by a regional registry (ARIN, RIPE, APNIC…). This lookup shows the owning organization, the block's range and name, and where it's registered — useful for abuse reports and for knowing who's really behind a server.
How to read your ip whois lookup results
This shows who owns an IP block, from the regional registry (ARIN, RIPE, APNIC and others), including the network name and abuse contact.
The abuse contact is who to notify about spam or attacks coming from that IP.
Common problems and how to fix them
You are getting attacked from an IP
Use the abuse contact shown here to report it to the network operator responsible for that block.
Common questions.What is IP WHOIS?
A lookup of who is assigned an IP address or block, served by the regional internet registries.
Who owns an IP address?
IPs are allocated to networks (ISPs, hosts, companies). IP WHOIS shows the organization and its abuse contact.