Mail Exchange (MX) is the exchange of e-mail addresses. In this technique, MX records are used to enter several e-mail addresses with different priorities on different mail servers
. If a mail server is not available, then another e-mail address with a lower priority
on another mail server is used.The priority of the e-mail address is determined by a prefixed digit
. TheMX record shows under which Fully Qualified Domain Name
(FQDN) the mail server canbe
If the actual mail address is email@example.com, then another one with higher priority can be firstname.lastname@example.org
. The mailserver with the lowest priority is contacted first.
With the Mail-Exchange technique, several mail servers can accept mails, so that there are no bottlenecks in case of high mail volume or if one server fails or cannot be reached.
The mails will be delivered no matter what. Furthermore, the MX technique has the advantage that incoming mails are not collected on many computers.