DNS & domain lookup

Reverse DNS Lookup

Resolve an IPv4 or IPv6 address back to its hostname via PTR records. Free reverse DNS lookup over live DNS — essential for email deliverability checks.

Reverse DNS lookup

Enter an IPv4 or IPv6 address to find the hostname it resolves back to (PTR).

What this reverse DNS lookup does

Resolves an IPv4 or IPv6 address to its hostname
Builds the correct in-addr.arpa / ip6.arpa query
Queries live over DNS-over-HTTPS
Handles compressed IPv6 addresses
One-click copy of the resolved hostname
Shows the exact reverse zone that was queried

Common use cases

  1. 1Identifying the host behind an IP address
  2. 2Checking a mail server's reverse DNS (PTR) for deliverability
  3. 3Investigating a suspicious IP in your logs
  4. 4Verifying PTR records after configuring them
  5. 5Confirming forward and reverse DNS match
  6. 6Auditing server hostnames

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About reverse DNS (PTR)

Reverse DNS maps an IP address back to a hostname using a PTR record, published under the special in-addr.arpa (IPv4) or ip6.arpa (IPv6) zone. Unlike forward records, PTR records are controlled by whoever owns the IP block — usually your hosting provider.

Reverse DNS matters most for email: receiving servers often reject or flag mail from IPs whose PTR record is missing or does not match the sending hostname. Set a PTR that matches your mail server's forward record for the best deliverability.

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HostCloud.in  ·  Pune, India  ·  Serving 34,987+ Websites Since 2020

FREQUENTLY ASKED QUESTIONS

Got Questions? We Have Answers.

What is reverse DNS?

Reverse DNS maps an IP address back to a hostname using a PTR record, the opposite of a normal (forward) lookup.

Why does reverse DNS matter for email?

Receiving mail servers often reject or flag mail from IPs with no PTR record or a PTR that does not match the sending hostname. Matching reverse DNS improves deliverability.

Who controls the PTR record?

The owner of the IP block — usually your hosting or network provider — not the domain owner. You typically request PTR changes from them.

Why is there no PTR for my IP?

Many IPs simply have no reverse DNS configured. For mail servers, ask your provider to set a PTR that matches your hostname.

Does this support IPv6?

Yes. Enter an IPv6 address and the tool builds the correct ip6.arpa query, handling compressed (::) notation.

Is the lookup live?

Yes. PTR records are resolved in real time over DNS-over-HTTPS.