To add a host to the lists
Click the + icon. The Add User-defined SMTP Server dialog displays.
Enter a name for the host in the Name field.
Select the type of host from the Type drop-down menu. The following setting(s) change, depending on the host type selected.
If you selected:
Range – enter the starting and ending IP addresses in the Starting IP Address and Ending IP Address fields.
FQDN – enter the FQDN hostname in the FQDN Hostname field.