MX Record for Mail Exchange.

An entry in a domain name database that identifies the mail server that is responsible for handling e-mails for that domain name. Mail Exchange record is part of the zone file.

When more than one MX record is entered for any single domain name that is using more than one mail server, the MX record can be prioritized with a preference number that indicates the order in which the mail servers should be used. This enables the use of primary and backup mail servers.