Which DNS record maps an IP address to a hostname and is used most often for DNS lookups?

Which DNS record maps an IP address to a hostname and is used most often for DNS lookups?

• A. PTR (Pointer)
• B. CNAME (Canonical Name)
• C. A (Address)
• D. NS (Name Server)

Answer: (C)

In DNS, the direction of the lookup determines the record type. A records are used for forward lookups: they map a domain name to an IPv4 address, and this is the most common type of DNS lookup you’ll see when connecting to websites. The opposite direction—finding the hostname for a given IP address—is handled by PTR records as part of reverse DNS. PTR records map an IP address back to a hostname and are used in scenarios like mail server checks and network diagnostics where you want to identify the domain associated with an IP. Other record types include CNAME, which aliases one name to another, and NS, which lists the authoritative name servers for a domain. So, for mapping an IP address to a hostname, the appropriate type is PTR, used for reverse lookups; for everyday forward lookups, A records are the workhorse.

In DNS, the direction of the lookup determines the record type. A records are used for forward lookups: they map a domain name to an IPv4 address, and this is the most common type of DNS lookup you’ll see when connecting to websites. The opposite direction—finding the hostname for a given IP address—is handled by PTR records as part of reverse DNS. PTR records map an IP address back to a hostname and are used in scenarios like mail server checks and network diagnostics where you want to identify the domain associated with an IP. Other record types include CNAME, which aliases one name to another, and NS, which lists the authoritative name servers for a domain. So, for mapping an IP address to a hostname, the appropriate type is PTR, used for reverse lookups; for everyday forward lookups, A records are the workhorse.