↩️ Reverse IP Lookup
Find the hostname behind any IPv4 or IPv6 address with reverse DNS (PTR), including forward confirmation.
🔐 Queries are sent to public DNS-over-HTTPS resolvers (Cloudflare, Google) that receive the address you check. Nothing is stored by 0Appz.
📋 Reverse DNS result
How to use this tool
Overview
Reverse IP Lookup - Free PTR Record Checker performs reverse DNS lookups for any IPv4 or IPv6 address using DNS-over-HTTPS, then goes one step further than most tools: it forward-confirms the result. First the PTR record in the in-addr.arpa or ip6.arpa zone reveals the hostname; then the tool resolves that hostname forward and checks whether it points back to the IP you entered. That forward-confirmed reverse DNS (FCrDNS) check is exactly what mail servers verify before accepting messages, which makes this tool useful for diagnosing email deliverability, checking server configuration, verifying that a crawler or monitoring bot is legitimate, and investigating suspicious log entries. Queries go from your browser to Cloudflare or Google DoH resolvers; nothing is stored.Frequently asked questions
What is reverse DNS? +
Reverse DNS (rDNS) maps an IP address back to a hostname using PTR records in the special in-addr.arpa (IPv4) and ip6.arpa (IPv6) zones. The Reverse IP Lookup - Free PTR Record Checker queries those records through DNS-over-HTTPS.
What is forward confirmation (FCrDNS)? +
A PTR alone proves nothing — anyone controlling the zone can set it. Forward-confirmed reverse DNS checks that the hostname also resolves forward to the same IP. Mail servers commonly require FCrDNS before accepting messages.
Why do many IPs have no PTR record? +
Residential and consumer connections usually do not publish PTR records, and many hosting providers only add them on request. A missing PTR is normal for client IPs and a red flag for mail servers.
Is the lookup private? +
Yes. Queries go from your browser to Cloudflare or Google DNS-over-HTTPS resolvers with a fallback between them. Nothing is sent to 0Appz and no history is stored.