From time to time, it may be necessary to have to review the MTA logs, usually when troubleshooting the sending of email after it has passed through the SMTP Plugin chain and its transferred to the end point.
From the firmware version 8.3 onwards, the MTA Logs are no longer enabled by default. You have to enable the MTA logging from the diag.html page.
To do this, go to the diag.html page of the appliance, by changing the URL of your Sonicwall Email Security so that the page name after the last / is diag.html and browse to this page. Eg, https://emailsecurity/diag.html
When you have gone to the /diag.html page of the appliance, you will be presented with the Diagnosis Suite. Please ensure that you read and understand the disclaimer mentioned on this page.
Now select Server Settings, and on this page, you should see the "PMTA Logging Directives" field, it contains the following fields:
Log Transfer Failures
Select the required data you want to enable MTA Logging for, and scroll down to the bottom of the page to apply the settings.
To view the data, go back to the main page of the Email Security Interface, and go to System | Advanced | Download System/Log Files, download the pmta:mta-log and you will see the MTA Logs as specified above.