In order to send mail to a domain, the sending mail server has to perform a DNS lookup on the target domain to find out what IP address the receiving mail server has.
You can specify what DNS servers you want SmarterMail to use for this lookup. The default setting is to use the Private Network DNS Servers, however, there may be instances where you want to have SmarterMail use a specific DNS Server for these lookups.
To change this setting is very simple.
Log into SmarterMail as “Admin”
Click on the “Settings” icon at the top.
Click on “General Settings” in the left window pane.
Click on the “Server Info” tab.
Modify the values for “IP of Primary DNS” and “IP of Secondary DNS” to point to your desired DNS servers. Click “Save” at the top when completed.
SmarterMail will now use the custom DNS servers to perform lookups when sending mail.