SMTP IIS 6.0 mail queue backlog RRS feed

  • Question

  • User-1807601726 posted

    We have SMTP installed on Windows Server 2012 R2 - IIS 6.0 Manager.

    The issue is when our SMTP service becomes quite busy throughout the day, there will be a large amount of emails waiting to be sent out under the directory of C:\inetpub\mailroot\Queue

    The queue will be waiting on 45000 + emails to be sent out, the queue will keep on growing and emails will eventually stop being delivered to clients without the SMTP service crashing.

    The strange thing is that if the mail queue is on a low amount (about 40 - 100) the emails will be sent out instantly and the queue will not increase dramatically, it's only when we leave SMTP running for a few days, the mail queue increases dramatically and then eventually emails stops being sent out.

    This happens in our Physical and our Cloud AWS environment, so it has to do with the SMTP Service itself. We have gone through all the Event Viewer and SMTP logs to see if there is anything out of the ordinary, but there is not an indication of an actual crash that would cause the queue to increase and the emails to fail. When the issue happens, the SMTP logs come through at a slow rate as well.

    We are currently using an alternative solution called Hmail which is an open source SMTP service, and this is working without any issues, but we would like to use Microsoft SMTP service rather. NSlookup can resolve to mail records on the server.

    Does anyone have ideas where we can start narrowing down the problem?


    Thursday, August 18, 2016 9:41 AM

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