Reverse DNS (PTR) Lookup
Resolve an IPv4 or IPv6 address back to its hostname via its PTR records.
Frequently asked questions
What is reverse DNS?
Reverse DNS resolves an IP address back to a hostname using a PTR record — the opposite of a normal (forward) lookup.
Why does an IP have no PTR record?
PTR records are optional and controlled by whoever owns the IP block. Many addresses have none, or a generic ISP-assigned name.
Why does reverse DNS matter for email?
Mail servers often reject or downrank senders whose sending IP lacks a matching PTR record, so a correct reverse DNS entry improves deliverability.
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