N10-005 · Question #362
Which of the following records allows for reverse DNS lookups?
The correct answer is C. PTR. PTR (Pointer) records are DNS record types that map an IP address back to a hostname, enabling reverse DNS lookups.
Question
Which of the following records allows for reverse DNS lookups?
Options
- AAAAA
- BA
- CPTR
- DCNAME
How the community answered
(26 responses)- A4% (1)
- B4% (1)
- C85% (22)
- D8% (2)
Why each option
PTR (Pointer) records are DNS record types that map an IP address back to a hostname, enabling reverse DNS lookups.
AAAA records perform forward DNS lookups by mapping a hostname to an IPv6 address, not an IP address to a hostname.
A records perform forward DNS lookups by mapping a hostname to an IPv4 address, which is the opposite of a reverse lookup.
A PTR record is the DNS record type used for reverse DNS resolution, stored in the in-addr.arpa (IPv4) or ip6.arpa (IPv6) zones. When a client queries the IP address 192.0.2.1, the DNS resolver looks up 1.2.0.192.in-addr.arpa and returns the associated PTR record containing the hostname, which is the reverse of a standard forward lookup.
CNAME (Canonical Name) records create an alias from one hostname to another hostname and are used for forward lookups, not reverse DNS resolution.
Concept tested: DNS PTR record for reverse DNS lookup
Source: https://learn.microsoft.com/en-us/windows-server/networking/dns/manage-resource-records
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