Reverse DNS Lookup (rDNS)
Perform reverse DNS lookups to find the hostname associated with an IP address. Essential for email server verification and security analysis.
Test with Common IPs:
About Reverse DNS (rDNS)
Reverse DNS (rDNS) lookup translates an IP address back to its associated hostname. This is the opposite of a standard DNS lookup which translates hostnames to IP addresses.
Why rDNS matters for email:
- Spam Prevention: Many email servers reject mail from IPs without rDNS
- Reputation: Proper rDNS configuration indicates legitimate mail servers
- Deliverability: Missing rDNS can cause emails to be filtered or blocked
- Authentication: rDNS is often checked as part of anti-spam measures
- Compliance: Some email providers require matching forward/reverse DNS
Best practice: Email servers should have rDNS records that resolve back to a hostname that forward-resolves to the same IP address (matching rDNS).