Reverse DNS (PTR)
Resolve the hostname associated with an IP address.
Reverse DNS (rDNS) translates an IP address into its associated hostname via a PTR record, using the special zones in-addr.arpa (IPv4) and ip6.arpa (IPv6). It is key to mail server reputation: many receivers reject email from IPs without a valid PTR.
Reverse DNS FAQ
A PTR (pointer) record maps an IP address to a hostname. It's the opposite of an A record: instead of name→IP, it does IP→name. It's used for reverse DNS.
Many mail servers check that the sending IP has a valid PTR matching the domain. If it's missing or doesn't match, your emails may be rejected or flagged as spam.
The PTR is managed by the owner of the IP block, usually your hosting provider or ISP, not the domain owner. To set it on your own IP you must request it from your provider.
Yes. This tool supports both IPv4 (in-addr.arpa zone) and IPv6 (ip6.arpa zone), automatically expanding the address into its nibble form.
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