• Local Mail Exchanger
  If the lowest number mail exchanger points to an IP on this server the server will be configured to accept mail locally and from outside the server.
• Backup Mail Exchanger
  If a mail exchanger other than the lowest points to an IP on this server, the server will be configured to act as a backup mail exchanger.
• Remote Mail Exchanger
  If there are no mail exchange that point to an IP on this server the server will be configured to not accept mail locally and send mail to the lowest MX record.

Note: Automatic detection of MX configuration is not possible if MX entries do not resolve (ie: you mistype a domain name or enter one that does not exist). If your MX configuration is set to auto and you add or edit an MX record that does not resolve you will see a warning and MX configuration will default back the last known setting.

If you have ips that are not bound to any network device on this server and you would like automatic selection to consider them as local you can edit the list of additional local ips here.

Configure server to always accept mail. Mail will be delivered locally on the server when sent from the server or outside the server.

Configure server as a backup mail exchanger. Mail will be held until a lower number mail exchanger is available.

Configure server to not accept mail locally and send mail to the lowest MX record.