MX record

An MX (Mail Exchange) record is a type of DNS (Domain Name System) record that tells mail servers where to deliver inbound email for a domain. It specifies the hostname(s) of the mail server(s) responsible for receiving messages and their priority. 

MX records are mandatory for a domain to receive email. If no MX records are present, the domain cannot accept incoming mail. 

Key points: 

• MX records are not used for sending email – that’s handled by SMTP and the sender’s mail infrastructure 
• They point to a fully qualified domain name (FQDN), not an IP address 
• Lower priority numbers indicate higher delivery priority 

In Mailgun’s case, setting your domain’s MX records to point to Mailgun enables inbound email routing and processing features.