DNS MX Records

What is a DNS MX Record?

The DNS 'Mail Exchange' record specifies where to direct mail to a mail server for a specific domain.

It indicates how email messages should be routed per the SMTP protocol.

The Mail Transfer Agent (MTA) server software is responsible for querying a domain's DNS MX records. It does so to identify the mail servers for email recipients and establishes an SMTP connection with one of those mail servers, starting with the prioritized domains.

The above table displays the MX records an administrator would need to add to their domain DNS to activate Google Workspace mail services.

The priority numbers indicate the preference of SMTP connection attempts; the lower the priority, the more preferred. For example, an MTA attempting to connect to Google mail servers will start with 'aspmx.l.google.com' first because it has a priority of 1. In the event of a message send failure, the MTA will default to 'alt1.aspmx.l.google.com' and so on.

TTL is an abbreviation for  Time To Live, which specifies how long (measured in seconds) a DNS record should be considered valid before it needs to be refreshed.