This procedure applies to SmarterMail 8.x - 12.x:

Before configuring SmarterMail as a backup MX server, you must ensure that the server is listening on the appropriate IP address(es):

Log in to SmarterMail as the system administrator

Click the Settings icon.

Expand the Bindings folder in the navigation pane.

Click Ports. A list of ports will load in the content pane. By default, ports 110, 143 and 25 are already set up. If necessary, add any alternative ports you may need SmarterMail to listen on.

Click IP Addresses. A list of IP addresses will load in the content pane.

Select each IP address you wish to listen on and click Edit. NOTE: You can only edit one IP address at a time.

Select the port(s) you would like the IP address to listen on and click Save.

Your server is now set up to listen on the selected ports for the IPs they have been added to.

Follow these steps to configure SmarterMail as a backup MX server:

Log in to SmarterMail as the system administrator.

Click the Settings icon.

Expand the Routing folder in the navigation pane.

Click Incoming Gateways.

Click New in the content pane toolbar.

Click the Options tab.

In the Gateway Mode field, select Backup MX from the list.

Type the IP address or IP range in the appropriate field(s) for the mail server you're creating the backup MX for. (Typically, this is your primary mail server IP or IP range).

Click the Spam tab and modify the spam action settings, if necessary.

Click Save.

Click General Settings in the navigation pane.

Click the Spool tab.

Change the Retry Intervals field to 10, 10, 10, 1440.

Click Save.

In DNS, add secondary MX records that point to the new servers IP address. Be sure to set the preference value higher than the main MX record.