The 'PTR' Resource Record (RR) is standarized in RFC 1035 and are used only for reverse-mapping zones and are the corollary of the address 'A' or 'AAAA' RRs. PTR RRs map an IPv4 or IPv6 address to a name. This process is sometimes also referred to as rDNS or Reverse DNS.
Pointer to a canonical name. Unlike a CNAME, DNS processing stops and just the name is returned. The most common use is for implementing reverse DNS lookups, but other uses include such things as DNS-SD.
'PTR' RR Syntax
In this example, this is the last octet of a class C [/24] network IP [188.8.131.52]. The reverse lookup zone would be '45.16.105.in-addr.arpa' (Notice the octets are listed in reverse order from the IP.)
This is the records time to live value (in seconds). If there is no TTL specified, the zone's default $TTL Directive will be used.
This content was last updated on December 10, 2020
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