Next, SLmail will prompt you for the Domain Name Server (DNS) you would like SLmail to use. SLmail requires a valid Internet DNS server in order to properly route outbound mail.
SLmail Installation DNS Server dialog box
Enter the IP address of the DNS server and then click Next .
You will then be asked whether or not the DNS server is installed on the local machine (same machine as SLmail).
UDP Port Configuration dialog box
If you use an external DNS server you will need to use port 53 (default port) for resolution, click Next to continue.
If you have a DNS server installed on the same machine there will be port conflict when trying to get DNS resolution, so the port is changed to 54. If you have a DNS server installed on the same machine and you wish to change the port setting manually, make sure that Yes is selected and then click the Advanced button.
MX Port Configuration dialog box
Enter or select the alternate port in the list box and then click OK .