Reverse DNS lookup
Verify mail server and infrastructure hostnames before a receiver rejects your traffic for a missing or mismatched PTR.
How it measures
- The PTR record is fetched through a public resolver.
- Each returned name (up to five) is resolved forward (A for IPv4, AAAA for IPv6) and compared with the original address.
Limits
- Private, loopback, link-local and other special-purpose addresses are refused.
- One resolver view; PTR changes propagate like any other record.
Troubleshooting
- No PTR record
- PTR records live in the address owner's zone. Ask your hosting or network provider to publish one for your mail server.
- Not forward-confirmed
- Point the PTR at a hostname whose A/AAAA record is exactly this address, or add the address to that hostname.