Reverse DNS
What name does this address claim?
Look up the reverse name of one or more public IP addresses, then check that the name resolves back (forward-confirmed reverse DNS).
Looks things up straight from your browser. When you press the button, this page asks Google Public DNS directly, with no cookies and no referrer. We never see the lookup. Private addresses and internal names are never sent. Nothing is saved, and reloading clears everything.
Private and reserved addresses are skipped and never sent to a resolver.