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Reverse DNS Lookup

Find the hostname of an IPv4 or IPv6 address and check that it resolves back (FCrDNS).

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How to use the Reverse DNS Lookup

  1. 1

    Enter an IP address.

  2. 2

    Click Look up.

  3. 3

    See its PTR hostnames and whether they resolve back to the same IP.

Frequently asked questions

How does the lookup work?

Our server asks public DNS resolvers (Cloudflare 1.1.1.1 and Google 8.8.8.8) and shows you the answer. Nothing is stored.

Why does reverse DNS matter?

Mail servers check that a sending IP has a PTR record that resolves back to it. Without one, email is more likely to be marked as spam.