Reverse DNS
Look up the hostname (PTR record) for any IPv4 or IPv6 address.
Ready to Analyze
Enter a target value above or click any sample preset chip to generate real-time diagnostic output.
About the Reverse DNS Tool
The Reverse DNS tool turns an IP address into a hostname by querying the PTR (pointer) record for that IP. PTR records live in the `in-addr.arpa` (IPv4) or `ip6.arpa` (IPv6) reverse zones, and are usually configured by the network operator that owns the IP — not by the end user or hosting customer. Reverse DNS is critical for outbound mail deliverability: most mail servers require the sending IP to have a valid PTR that matches its forward A record before they accept mail.
System administrators run reverse DNS lookups to investigate suspicious traffic, verify that a mail server's PTR aligns with its EHLO/HELO banner, audit shared-hosting IPs, and identify the ISP or cloud provider behind an IP. Security teams use PTR lookups during incident response — a PTR ending in `.amazonaws.com` versus `.compute.hetzner.cloud` versus `.somewhere-residential.net` tells you very different stories about what an IP is likely doing.
Not every IP has a PTR record. Cloud providers assign generic PTRs by default (`ec2-1-2-3-4.compute-1.amazonaws.com`) which you can usually override on request. Consumer ISPs assign residential-style PTRs. IPs with no PTR at all often signal poorly managed infrastructure or block-listed ranges.
Enter the required value in the input field above (domain, IP, URL, or text depending on the tool).
Click the action button to run the check — results are computed instantly from our edge network.
Review the parsed output, key fields and any warnings shown in the result card.
Copy the result, share the page URL, or jump to a related tool from the sidebar to continue debugging.
- IPv4 and IPv6 reverse DNS in one lookup
- Essential check for mail server operators
- Reveals cloud provider, ISP or hosting service
- Detects missing or generic PTR records