PTR (Reverse DNS) Generator
Generate IPv4/IPv6 PTR records and check reverse DNS.
IPv4 Reverse DNS Generator
Generate valid PTR records for IPv4 addresses (in-addr.arpa).
What is a PTR Record?
A PTR (Pointer Record) is a DNS record type that maps an IP address back to a domain name. It is the exact opposite of an A record (which maps a domain to an IP), hence the name 'Reverse DNS'.
Importance of Reverse DNS
Reverse DNS (rDNS) is crucial for anti-spam verification. Many email servers reject emails from IPs without a valid PTR record. It is also used for network diagnostics and logging to identify hostnames.
in-addr.arpa & ip6.arpa
These are the two top-level domains used for reverse lookups. IPv4 uses in-addr.arpa with octets reversed (e.g., 1.2.3.4 becomes 4.3.2.1.in-addr.arpa). IPv6 uses ip6.arpa with all hex digits reversed and separated by dots.
TTL (Time To Live)
TTL determines how long (in seconds) a DNS record is cached by servers. For PTR records, a longer TTL (e.g., 86400s/1 day) is usually appropriate unless you plan to change your server infrastructure frequently.