MX record (Mail Exchange record)

An MX record (Mail Exchange record) is a domain name system (DNS) server record that contains information about which mail server the domain uses to receive mail.

An MX record can point to a mail server or a proxy server when there is a hosted mail filtering process in place. In an on-premises deployment, the administrator can also point MX records to a firewall that uses internal forwarding rules to redirect inbound messages to an edge transport server handling Internet-facing mail flow or an Exchange mailbox server.