Which DNS record would you use to alias one domain to another?

• A. CNAME
• B. A
• C. PTR
• D. NS

Answer: (A)

A CNAME record is used to create an alias from one domain name to another. When a client looks up the alias, DNS responds with the canonical domain name, and the resolver then fetches that domain’s A or AAAA records to obtain the actual IP address. This lets you have multiple domain names point to the same destination without duplicating IPs. For example, you can set www.example.com to alias example.com, so both resolve to the same site.

This is the appropriate choice for aliasing because other common records serve different purposes: an A record maps a name directly to an IP address; a PTR record is used for reverse lookups (IP to domain); and NS records specify which servers handle the DNS for a zone. Remember, CNAME is best for aliasing names to another domain, not for mapping to an IP address directly or for zone management tasks.