What is an MX record used for?

What is an MX record used for?

• A. Locating the mail server for a domain
• B. Providing the host's IP address
• C. Mapping domain to a name
• D. Defining the canonical name

Answer: (A)

The main concept here is how DNS directs email delivery using MX records. An MX (Mail Exchange) record designates which mail server handles inbound mail for a domain, and it includes a priority value. When a message is sent to an address at that domain, the sender’s mail transfer agent queries DNS for the domain’s MX records, selects the mail server with the lowest priority, and connects to that host to deliver the email. The server named by the MX record must also have an A (or AAAA) record so its IP address can be found. If multiple MX records exist, the system can fail over to the next highest-priority server if the primary is unavailable. This is distinct from A records, which map a domain directly to an IP address, and from CNAME records, which alias one name to another.

The main concept here is how DNS directs email delivery using MX records. An MX (Mail Exchange) record designates which mail server handles inbound mail for a domain, and it includes a priority value. When a message is sent to an address at that domain, the sender’s mail transfer agent queries DNS for the domain’s MX records, selects the mail server with the lowest priority, and connects to that host to deliver the email. The server named by the MX record must also have an A (or AAAA) record so its IP address can be found. If multiple MX records exist, the system can fail over to the next highest-priority server if the primary is unavailable. This is distinct from A records, which map a domain directly to an IP address, and from CNAME records, which alias one name to another.