MX (Mail Exchanger) records are DNS (Domain Name System) records that specify the mail servers responsible for receiving incoming email for a domain. These records play a crucial role in email delivery by directing emails to the correct mail servers.

Here’s how MX records work and how they should be used:

1. Email Routing: When someone sends an email to an address associated with your domain (e.g., user@example.com), their email server performs a DNS lookup to determine where to send the email. It looks for the MX records of your domain to identify the mail servers that should handle incoming mail.

2. Priority and Preference: MX records can have different priorities assigned to them using a numeric value called the preference or priority number. The lower the number, the higher the priority. Email servers attempt to deliver emails to the mail server with the lowest priority first. If that server is unavailable, it moves to the next highest priority server until the email is successfully delivered.

3. Multiple MX Records: It is common to have multiple MX records for a domain, allowing for redundancy and load balancing. Each MX record points to a different mail server, and the preference numbers determine the order in which they are attempted. If the server with the highest priority is unavailable, the next server in the priority list is tried.

4. Configuring MX Records: To configure MX records, you need to access your domain’s DNS settings. You typically create or modify MX records using your domain registrar’s or DNS provider’s control panel. Each MX record consists of the following information:
– Hostname: The domain or subdomain for which you are configuring the MX record (e.g., example.com or mail.example.com).
– Priority: The preference number indicating the priority of the mail server. Lower numbers have higher priority.
– Destination: The hostname or IP address of the mail server responsible for handling incoming email.

Example:
“`
example.com. IN MX 10 mail.example.com.
example.com. IN MX 20 backup.mail.example.com.
“`

5. Testing and Troubleshooting: After configuring MX records, it’s essential to test the email delivery to ensure everything is working correctly. You can send test emails and monitor their successful delivery. If there are any issues, double-check the MX record configurations, ensure the mail servers are correctly set up, and verify that the servers are reachable and properly configured to handle incoming email.

Properly configuring MX records ensures that incoming emails for your domain are routed to the correct mail servers. It allows you to control where your email traffic is directed, implement redundancy, and ensure reliable email delivery for your domain.