Cactus
Check an IP address's reputation
Enter an IP address to see who owns it, its reverse DNS name, and whether it appears on public blocklists used to flag spam and abuse.
How this works
- We only run public DNS lookups (reverse DNS, Team Cymru for the network owner, and a sample of DNS blocklists). We never connect to the IP itself.
- The IP you enter is used to produce this result and isn't stored.
Frequently asked questions
What does an IP address reputation tell me?
It shows who owns the IP (the network/ASN and country), its reverse DNS name, and whether it appears on public blocklists used to flag sources of spam and abuse. It's useful for checking a suspicious sender, server, or login-alert IP.
Does being on a blocklist mean an IP is dangerous?
Not always. Blocklists can lag or list a whole shared range, and a clean IP isn't a guarantee of safety. Treat a listing as a strong hint to be cautious, not proof - we check a sample of public lists, not every one.