Interview Questions/Phone Screen/DNS A Record vs CNAME
BeginnerPhone
2 min

DNS A Record vs CNAME

DNSNetworkingWeb
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Interview Question

What is the difference between an A record and a CNAME record in DNS, and when would you use each?

Key Points to Cover
  • A record maps a name to an IPv4 address
  • CNAME maps a name to another canonical name
  • Use CNAME for aliasing; A for direct address; apex usually requires A/ALIAS
Evaluation Rubric
Defines A record correctly34% weight
Defines CNAME and purpose33% weight
Gives valid usage constraints (apex)33% weight
Hints
  • 💡Some DNS providers offer ALIAS/ANAME for apex CNAME-like behavior.
Potential Follow-up Questions
  • What about AAAA records?
  • How do TTLs impact failover?
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