[ IP to Hostname | PTR Record Resolution | Mail Server Verification ]
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What is Reverse DNS?
Maps IP addresses back to domain names using PTR records.
Common Uses:
Email server verification, network troubleshooting, identifying hosts.
Example:
8.8.8.8 → dns.google
What is Reverse DNS? Reverse DNS (rDNS) translates an IP address back to a hostname using PTR (pointer) records. It's the opposite of regular DNS lookups.
Common Uses: Mail server verification (prevents spam blocking), network diagnostics, identifying server owners, security investigations, troubleshooting email delivery issues.
Why it matters: Many mail servers reject emails from IPs without proper reverse DNS records. ISPs and email providers use rDNS to verify sender legitimacy.
Related tools: DNS Lookup · WHOIS Lookup · IP Geolocation
What does reverse DNS return? It returns a hostname (PTR record) associated with an IP address (for example, many providers return a hostname under their domain).
Is missing reverse DNS always a problem? Not for normal browsing. It matters most for email sending IP reputation, some security tooling, and server identification.
Why can't I set PTR records in my domain DNS? PTR lives under the reverse zones controlled by the IP owner. You need the ISP/cloud provider to set it.
What should I check next? Use DNS Lookup for forward records and WHOIS to understand ownership/registration details.