The DNS record that allows you to alias both services to the same record (IP address).

• A. A
• B. MX
• C. PTR
• D. CNAME

Answer: (D)

This question hinges on how DNS can make multiple names share the same IP by aliasing. A CNAME record creates an alias from one domain name to another domain name. You can point several service names to a single canonical name, and that canonical name has an A (or AAAA) record with the actual IP address. When a resolver looks up any of the alias names, it follows the CNAME to the canonical name and then retrieves the IP from its A/AAAA record. So, both services end up resolving to the same IP address through that single canonical name. By contrast, an A record directly maps a name to an IP, MX specifies mail servers, and PTR is for reverse DNS mappings, none of which provide the aliasing behavior described.