Cisco Certified Support Technician (CCST) NetworkingIP ServicesEasy
A network engineer is troubleshooting a DNS resolution issue. Users can ping internal servers by their IP addresses but cannot access them by their fully qualified domain names (FQDNs). Which DNS record type is primarily responsible for mapping a hostname to an IPv4 address?
- APTR record
- BA record
- CNS record
- DMX record
Show answer & explanationAnswer & explanation
Correct answer: B. A record
An 'A' record (Address record) in DNS is used to map a hostname to an IPv4 address. This is the fundamental record type for forward DNS lookups.
Why the other options are wrong
- A. PTR records are for reverse DNS lookups (IP to hostname), not forward lookups.
- C. NS records delegate a DNS zone to an authoritative name server.
- D. MX records are for mail exchange servers, not general hostname-to-IP mapping.
DNS A Record
An 'A' (Address) record is a fundamental DNS record type that maps a hostname to an IPv4 address.
- Used for forward DNS lookups.
- Essential for resolving domain names to IP addresses.
- One of the most common DNS record types.
Memory trick: DNS records are like a phonebook, and 'A' is for 'Address' (IPv4).