Use the WebAdmin Interface to configure the SMTP module. Open the Mail pages in the Settings realm, then open the SMTP pages.
Use the Log setting to specify what kind of information the SMTP module should put in the Server Log. Usually you should use the Major (message transfer reports) or Problems (message transfer and non-fatal errors) levels. But when you experience problems with the SMTP module, you may want to set the Log Level setting to Low-Level or All Info: in this case protocol-level or link-level details will be recorded in the System Log. When the problem is solved, set the Log Level setting to its regular value, otherwise your System Log files will grow in size very quickly.
The SMTP module records in the System Log are marked with the SMTPI tag for incoming connections, with the SMTP tag for outgoing connections, and with SMTPW tag for connections used to wake up the back-up server.