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Reverse DNS (PTR) Lookup

reverse-dns

Convert IPv4 addresses into PTR query names and resolve the assigned hostnames.

Enter a target and run the tool.

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About Reverse DNS Lookup

A reverse DNS lookup translates an IP address back into the hostname assigned to it via a PTR (pointer) record in the in-addr.arpa zone. Reverse DNS matters in several real-world scenarios: receiving mail servers reject or penalize messages from IPs without matching forward and reverse DNS, security investigators use PTR lookups to attribute traffic to a provider or organization, log analysts enrich raw IP data with human-readable hostnames, and network operators verify that customer or rented IP blocks are correctly delegated. Our free reverse DNS lookup tool takes any IPv4 address you enter, builds the correct in-addr.arpa query name automatically, and resolves the PTR record through a public DNS-over-HTTPS resolver in real time. No need to remember the reversed-octet syntax or install dig. The tool runs in your browser, requires no signup, and has no per-query rate limit for normal use. It is especially handy when troubleshooting email deliverability — many corporate mail servers block messages from sending IPs whose PTR does not resolve or does not match the EHLO hostname.

Common use cases

  • Verify a mail server's sending IP has a matching forward and reverse DNS for deliverability.
  • Identify the owner or hosting provider of an unknown IP from server logs.
  • Enrich security alerts and traffic logs with human-readable hostnames.
  • Confirm reverse DNS delegation for a leased IP block.
  • Troubleshoot why an IP is being flagged as anonymous or untrusted.

How to use this tool

  1. Enter the IPv4 address you want to look up (for example, 8.8.8.8).
  2. Click "Lookup" — the tool builds the in-addr.arpa query name automatically.
  3. Review the PTR record returned, which is the hostname assigned to that IP.
  4. Optionally confirm forward and reverse match by looking up the returned hostname back to an A record.

Frequently asked questions

Is reverse DNS required?

It is not required by the DNS protocol itself, but mail servers and some security systems treat its absence as suspicious. For sending mail, matching forward and reverse DNS is best practice.

Why is the result empty?

No PTR record is published for the IP. The owner of the IP block has not delegated reverse DNS or has not configured a PTR for that specific address.

Can I do reverse DNS for IPv6?

IPv6 reverse lookups use the ip6.arpa zone with a different name format. This tool currently focuses on IPv4 addresses.

Can I change my reverse DNS?

Only the owner of the IP block (your hosting provider, ISP, or registry-issued allocation) can publish PTR records. Most providers offer a control-panel option for this.