What is the purpose of an MX record in DNS?

An MX record (Mail Exchanger) in DNS indicates to mail servers where to deliver email for a specific domain. It contains the domain name of the mail server and a priority.

Example:

# Record for domain example.com
# PRIORITY | HOSTNAME
10         mail.example.com.
20         backupmail.example.com.

Mail servers sending mail for @example.com will first attempt to deliver it to mail.example.com (priority 10). If this is unavailable, they will try backupmail.example.com (priority 20). A lower numerical value indicates a higher priority.

Thus, an MX record provides:

• Email delivery: Routes incoming mail to the appropriate mail servers.
• Redundancy: Allows specifying multiple servers with different priorities in case the primary is unavailable.
• Load distribution: In some configurations, it can be used to distribute traffic among multiple servers with the same priority.