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IP to Domain Lookup

Find domain names associated with IP addresses using reverse DNS PTR record lookups

Enter an IPv4 or IPv6 address to find reverse DNS (PTR) records. For example, 8.8.8.8. This can fail if the IP has no PTR—results may be empty.

Note: This shows PTR records only, not all domains that might resolve to the IP

About Reverse DNS (PTR) Lookup

⚠️ Important Limitation

This tool shows PTR records only - domains that the IP owner has configured to point back to this IP. It does NOT show all domains that might resolve to this IP address.

Reverse DNS (PTR records) is the opposite of regular DNS lookup. While regular DNS finds the IP address for a domain, reverse DNS finds the configured hostname for an IP address. Many IP addresses don't have PTR records configured.

PTR records are commonly used for email server verification, network diagnostics, and security purposes. Many mail servers require valid reverse DNS entries to accept emails.

Common use cases:

  • Email server configuration and troubleshooting
  • Network security and forensics investigations
  • Identifying server hostnames from IP addresses
  • Verifying domain ownership and configuration
  • Network mapping and reconnaissance
  • Analyzing shared hosting environments

Finding domains that point TO an IP:

  • Certificate Transparency: Search crt.sh or censys.io for SSL certificates
  • DNS Databases: Use SecurityTrails, PassiveTotal, or VirusTotal
  • Web Crawlers: Check Shodan, ZoomEye, or similar services
  • Historical Data: Use DNS history services to find past associations
  • Subdomain Tools: Use subdomain enumeration tools for known domains

Why PTR records are limited:

  • PTR records are optional and many IP owners don't configure them
  • Shared hosting can have hundreds of domains on one IP without PTR records
  • CDNs serve thousands of sites but may only have one PTR record
  • Many websites use the same IP without reverse DNS configuration

Important limitations:

  • PTR records are not mandatory and may not exist for all IP addresses
  • Private network IPs (192.168.x.x, 10.x.x.x) typically don't have public PTR records
  • Some hosting providers don't configure reverse DNS for shared hosting
  • Corporate firewalls may block reverse DNS queries
  • Results may vary depending on your DNS resolver

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