// domain tool
Free Reverse DNS tool.
Free reverse DNS lookup tool — find PTR records for any domain's IP addresses. Verify server hostnames and check email deliverability configuration.
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What Is Reverse DNS?
Reverse DNS (rDNS) uses PTR records to map IP addresses to hostnames — the opposite of a standard A record lookup. For IPv4, reverse lookups query the in-addr.arpa zone.
Properly configured reverse DNS is critical for email deliverability. Most spam filters check that the sending server's IP has a valid PTR record matching the server's hostname.
// more tools
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Full email security analysis