Reverse DNS (PTR) Lookup
Find the PTR (reverse DNS) hostname configured for an IP address.
About this tool
Reverse DNS maps an IP address back to a hostname using PTR records stored in the special in-addr.arpa (IPv4) and ip6.arpa (IPv6) zones. Enter an IP address and this tool returns the PTR hostname its owner has configured, if any.
Reverse DNS matters most for email: many receiving mail servers reject or penalize messages from IPs without a PTR record, or with a PTR that does not match the sending hostname (forward-confirmed reverse DNS). It is also handy for identifying servers found in logs.
Frequently asked questions
Who controls the PTR record for my IP?
The owner of the IP block — usually your hosting provider or ISP. Unlike normal DNS records, you cannot set PTR records in your domain's DNS zone; you must request them from whoever allocated the IP, or use their control panel if they expose one.
Why does my mail server need reverse DNS?
Spam filters treat a missing or generic PTR record as a strong spam signal. A proper setup has the PTR resolve to your mail hostname (e.g. mail.example.com), and that hostname resolve back to the same IP — this is called forward-confirmed reverse DNS (FCrDNS).
Can one IP have multiple PTR records?
Technically yes, but it is strongly discouraged. Multiple PTR records confuse FCrDNS validation and most providers configure exactly one PTR per address.