How to reverse-DNS an IP to hostnames

1. Enter the IP

   Type a public IPv4 or IPv6 address into the "IPv4 or IPv6" field (7–45 characters). Private ranges (10.x, 192.168.x, fe80::, etc.) are rejected — "Private IP reverse lookup not supported here."

2. What reverse DNS does

   The tool runs `dns.reverse(ip)` which queries the in-addr.arpa / ip6.arpa zones for PTR records. PTR is maintained by the IP's owner — many cloud IPs simply have no PTR set, so the result will be empty.

3. Press Run

   Result returns `hostnames` — an array. Multiple hostnames per IP are normal for shared web hosts; an empty array means no PTR record, NOT that the IP is offline.

4. Forward-confirm if it matters

   Reverse DNS is not authoritative. For abuse triage or mail rDNS checks, take a PTR result and run it through hostname-to-ip — only trust the mapping when forward and reverse agree.