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:
Understanding Reverse DNS
Reverse DNS looks up what domain name belongs to an IP address. It's the reverse of normal DNS, which finds the IP for a domain.
Why email servers need rDNS:
- Stops spam: Many servers block emails from IPs without rDNS
- Shows you're legit: Real mail servers have proper rDNS
- Gets delivered: Missing rDNS sends emails to spam
- Security check: Part of basic anti-spam filtering
- Required by some: Gmail and others need matching DNS records
The golden rule: Your mail server's IP should have rDNS that points to a domain, and that domain should point back to the same IP.