FCrDNS Check
Validate Forward-Confirmed reverse DNS (FCrDNS) for an IP address or hostname.
FCrDNS validates that an IP's PTR record points to a hostname that resolves back to the same IP. This is critical for email deliverability - many mail servers reject mail from IPs without valid FCrDNS.
What is FCrDNS?
Forward-Confirmed reverse DNS (FCrDNS) is a verification process that checks:
- PTR Record: The IP address has a reverse DNS (PTR) record pointing to a hostname
- Forward Match: That hostname resolves back (A/AAAA) to the original IP address
Why does it matter?
- Many email servers reject mail from IPs without valid FCrDNS
- Generic PTR records (like ISP defaults) may hurt email deliverability
- Properly configured FCrDNS improves trust and reputation
Related Tools
- Blacklist Check - Check if IP is on spam blacklists
- MX Lookup - Find mail servers for a domain
- SMTP Check - Test mail server connectivity