Reverse DNS Lookup

Convert a valid IPv4 or IPv6 address into its in-addr.arpa or ip6.arpa reverse-DNS name, then query its public PTR records through Google DNS-over-HTTPS. Results show the generated reverse name plus each returned hostname and TTL. PTR records are controlled by the IP address owner or hosting provider, not by ordinary forward-DNS settings, and many public addresses have no PTR. A returned hostname is public DNS metadata only: it does not prove ownership, identity, service health, or that forward DNS maps back to the same IP.

How to Use the Reverse DNS Lookup

Turn an IPv4 or IPv6 address into its reverse-DNS query name and inspect any public PTR hostnames returned.

  1. Enter a valid IPv4 address such as 8.8.8.8 or a valid IPv6 address.
  2. Select Run; the tool builds the matching in-addr.arpa or ip6.arpa name.
  3. Review the generated reverse name to confirm the intended address was queried.
  4. Read each returned PTR hostname and TTL; no answers can be a normal result.
  5. If forward-confirmed reverse DNS matters, separately resolve the PTR hostname and compare its A or AAAA answer with the original IP.

How reverse DNS works

IPv4 octets are reversed under in-addr.arpa. IPv6 hexadecimal nibbles are expanded and reversed under ip6.arpa before a PTR query is sent.

The organization controlling the address space delegates and manages reverse DNS, so changing your ordinary domain zone usually cannot alter the PTR.

Interpreting results

A PTR value is a public label, not verified identity or ownership. For mail diagnostics, also check whether the returned hostname resolves forward to the same address.

Common mistakes

  • Entering a hostname when this page requires an IP address.
  • Assuming no PTR record means the address is offline or invalid.
  • Treating a generic provider hostname as proof about the individual user of an IP.

Limitations, privacy, and acceptable use

The browser queries Google DNS-over-HTTPS, so results reflect public cached DNS and cannot reveal internal reverse zones. The entered IP is visible to that resolver.

Use PTR data for legitimate administration and research. Do not infer a person's identity from a hostname or use the result for harassment or unauthorized targeting.

FAQ

What is a reverse DNS or PTR lookup?

It starts with an IP address and asks DNS for PTR records that may name the host associated with that address, the reverse of a typical hostname-to-IP lookup.

Does the tool support both IPv4 and IPv6?

Yes. It constructs an in-addr.arpa name for IPv4 or the nibble-reversed ip6.arpa name for IPv6 before requesting PTR records.

Why does an IP address have no PTR record?

PTR publication is optional, and many consumer, shared, or temporary addresses do not have one. An empty answer can be normal rather than a lookup failure.

Who can change a PTR record?

Usually the ISP, cloud host, or organization controlling the IP allocation. Adding a PTR record to your domain's normal forward DNS zone will not configure reverse DNS for the address.

Does a PTR hostname prove who owns the IP?

No. It is a label published by the address-space operator and may be generic, stale, or shared. Use RDAP and other evidence for allocation research.

Should forward and reverse DNS match?

For mail servers, operators often configure forward-confirmed reverse DNS so the PTR hostname resolves back to the same IP. This tool checks PTR only and does not perform that forward confirmation.

What does TTL mean in the result?

TTL is how long a recursive resolver may cache the PTR answer. Changes made by an IP provider can remain stale until the previous TTL expires.

Which resolver is queried?

The lookup uses Google DNS-over-HTTPS from the browser, so it reflects public recursive DNS data visible to Google at that time.

Can I look up a private IP address?

The input may be syntactically valid, but public DNS normally has no meaningful PTR data for private or local address space. Internal reverse zones require your organization's own DNS resolver.

What is acceptable use for reverse DNS data?

Use public PTR data for legitimate administration, mail troubleshooting, and research. Do not treat a hostname as proof about a person or use lookups for harassment or unauthorized targeting.