Configuring Mail Protection
For e-mail originating from your organization to reach its destination, you need to configure Microsoft Forefront Threat Management Gateway to allow outbound e-mail to be sent to the Internet. Typically, you have one Exchange server that is configured to send e-mail messages to the Internet over the SMTP protocol. This is your SMTP gateway. The SMTP gateway must be able to perform DNS queries to find the mail exchanger (MX) record for the domain to which the e-mail message is being sent.
The following sections describe the configuration steps that are required to allow SMTP outbound e-mail through Forefront TMG: