Technical Tip: Configuring FortiMail to retain messages in queue when mail server is unavailable

Take the following steps to configure FortiMail to act as an alternative mail queue, retaining messages for a certain period of time, when the mail server is in maintenance mode or simply down (unavailable), follow these steps:

1. Set the mode to fail-open in the mail setting smtp-rcpt-verification configuration. This can be done by running the commands:

    

config mailsetting smtp-rcpt-verification

    set mode fail-open

end

2. Adjust the queue retry interval in the incoming queue to a lower value, such as 5 minutes (this will be the period of time required to mark the MTA as 'unreachable') by running the following commands:

    

config system mailserver

    config mail-queue

        edit incoming

            set queue-retry 5

    end

end

Once the connection to the backend server is available, FortiMail will start to deliver queued messages.

For more information on configuring FortiMail, refer to Email concepts and process workflow.