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Reverse DNS (PTR) Lookup

Check the PTR records for every IP address a domain resolves to. Shows forward-confirmed reverse DNS (FCrDNS) status for each address.

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What this PTR lookup tool checks

Enter any domain and this tool resolves all of its public IP addresses, then performs a reverse DNS (PTR) query for each one. It also checks forward-confirmed reverse DNS (FCrDNS): whether the PTR hostname resolves back to the original IP. Many spam filters and mail servers use FCrDNS as a signal of legitimacy, so misconfigured PTR records can quietly hurt your deliverability.

What each column means

  • IP address:each public IPv4 or IPv6 address the domain currently resolves to via A and AAAA records
  • PTR record:the hostname returned by a reverse DNS query on that IP, or “No PTR record” if none is configured
  • FCrDNS:“Verified” means the PTR hostname resolves forward back to the same IP, confirming the PTR is authoritative. “Not confirmed” means the PTR exists but the forward lookup does not match, or no PTR is set.

Frequently asked questions

What is reverse DNS / a PTR record?
Normal (forward) DNS resolves a hostname to an IP address. Reverse DNS does the opposite: given an IP address, it returns the hostname associated with it. This mapping is stored in a PTR record, which lives in a special zone of the DNS tree (in-addr.arpa for IPv4, ip6.arpa for IPv6). PTR records are typically set by whoever controls the IP block -- usually your hosting provider or ISP -- not by you in your own DNS zone.
What is forward-confirmed reverse DNS (FCrDNS)?
Forward-confirmed reverse DNS (FCrDNS) is a two-step verification. First, the PTR record for an IP is looked up to get a hostname. Second, that hostname is resolved forward to see if it returns the original IP. If the round-trip matches, the PTR is forward-confirmed. Many receiving mail servers and spam filters require or reward FCrDNS because it proves the IP owner controls both the IP and the hostname -- reducing the risk that the PTR was spoofed or misconfigured.
Why does my domain have no PTR record?
PTR records are controlled by the block owner -- the hosting provider or data center that allocated your IP -- not by you in your domain registrar or DNS panel. If no PTR is set, you need to ask your provider to create one (often called “reverse DNS” in their control panel). Some providers only offer PTR management on dedicated or static IP addresses, not on shared hosting.
Does a missing PTR record affect email deliverability?
It can. Many spam filters treat a missing PTR record as a weak negative signal. A present but not forward-confirmed PTR is treated similarly or worse. For best deliverability, your sending IP should have a PTR record that resolves to a hostname, and that hostname should resolve back to the same IP (FCrDNS). This is especially important for on-premise or self-hosted mail servers. Shared-IP senders using ESPs like SendGrid or SES are handled by the ESP's infrastructure, which typically has PTR records already configured.

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