Reverse DNS / PTR Lookup
Frequently Asked Questions about Reverse DNS (PTR) Lookup
What is Reverse IP (PTR) lookup and how does it work?
Reverse DNS resolves an IP address back to a hostname using dedicated in-addr.arpa (IPv4) or ip6.arpa (IPv6) zones. It identifies the canonical host name assigned to a specific network IP address.
Why is a valid PTR record critical for email deliverability?
Major email providers (Gmail, Microsoft, Yahoo) perform Forward-Confirmed reverse DNS checks (FCrDNS). Mail originating from IP addresses without matching PTR records is rejected or routed directly to spam folders.
What is the difference between an A record and a PTR record?
An A record maps a domain name to an IP address (forward lookup), while a PTR record maps an IP address back to its associated hostname (reverse lookup).
How do I configure a PTR record for my server?
PTR records must be created by the entity that owns the IP address allocation, typically your hosting provider or ISP, through your server hosting control panel.
Can I perform bulk reverse IP lookups?
Yes, bulk mode allows you to resolve PTR records for up to 100 IP addresses simultaneously and export the hostnames to a CSV file.
A reverse IP lookup performs a reverse DNS query for an IP address and returns its PTR hostname when one is published. This can help identify the server name associated with an address, verify mail-server configuration, investigate hosting infrastructure, and provide useful information when contacting a network or hosting provider.
Enter a valid IPv4 or IPv6 address to request the reverse record. Not every address has a PTR record, and the returned hostname is controlled by the address owner rather than the website, so it may be generic or outdated. Reverse DNS does not list every domain hosted on a shared server and should not be treated as proof of ownership.