Reverse DNS (PTR)
Find the hostname(s) associated with an IP address.
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Enter a ip address above and press Run to start the check.
About the Reverse DNS (PTR)
Reverse DNS performs a PTR (pointer) lookup to find the hostname or hostnames associated with an IP address. It works by querying the in-addr.arpa zone for IPv4 or ip6.arpa for IPv6, which the address block's owner controls. Reverse DNS is widely used by mail servers to verify senders, so a correct PTR record is essential for email deliverability and for identifying which host is behind an address.
How to use
- Enter the IPv4 or IPv6 address you want to look up.
- Run the query to retrieve the PTR record from the reverse zone.
- Review the returned hostname and confirm it matches the expected forward record.
Frequently asked questions
- What is a PTR record?
- A PTR record maps an IP address back to a hostname, the reverse of an A or AAAA record. It lives in the in-addr.arpa or ip6.arpa reverse DNS zone.
- Why does my IP have no reverse DNS?
- Reverse DNS is configured by whoever controls the IP block, usually your hosting provider or ISP. If no PTR record is set, the lookup returns nothing.
- Does reverse DNS affect email?
- Yes. Many receiving mail servers check that a sending IP has a valid PTR record, and often that it matches the forward DNS, before accepting mail.