You can stop and start mail service on the hosting appliance.

To have all of your outgoing mail sent through a central relay server, specify a Smart relay hostname.

Use the Reject... and RBL options to strengthen security for your mail service. Separate multiple domain names with a semi-colon (;).

Enter maximum file sizes for incoming and outgoing messages to limit bandwidth usage for all domains hosted on the appliance. (Between 0 and 999 MB. Note that entering 0 will disable the mail service.)