What Are MX Records?

Definition

MX Records (Mail Exchange Records) are a type of DNS (Domain Name System) record that directs incoming emails to the correct mail server for a domain. These records provide specific instructions, telling emails which server to go to so they reach the right inbox. If MX records are not set up properly, your domain will not receive emails. MX records also assign priority to mail servers. If one server goes down, another can handle email traffic. This keeps things running smoothly in case of emergencies.

Example

Suppose your domain is “mybusiness.com.” When someone sends an email to “info@mybusiness.com,” the sending server checks the MX records for your domain to find the correct mail server. Once it finds the right server, the email is delivered. If the MX records are missing or incorrect, the email may bounce back or fail to deliver at all.

How MX Records Affect Email Delivery

MX records directly impact how emails are delivered to your domain. They tell the email server of the sender which destination server to contact to deliver the email. Each MX record has a priority value, called a "preference" number. The lower the number, the higher the priority. For instance, if one mail server has a preference value of 10 and another has 20, emails will attempt to go to the server with priority 10 first. If that server is not available, the email will go to the next server in line—which, in this case, is 20.

Without correctly configured MX records, email delivery might be delayed or fail entirely. Proper setup means your emails will be able to get through, even if one of your mail servers experiences an issue.

How to Configure MX Records

Configuring MX records may vary depending on your exact provider. Still, here’s a general guide so that you know what to expect.

1. Go to DNS Settings. Access your DNS settings through your domain registrar or hosting provider.
2. Add the MX Records. Find the section labeled MX records and input your mail server’s hostname.
3. Set Priorities. If you have more than one mail server, assign each a priority number. The server with the lowest number gets the highest priority.
4. Save Changes. Once the records are added, save the changes. It may take some time for updates to spread through DNS servers.

Related terms

• Email Deliverability Rate

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