Exchange 2003 SMTP queue full of strange addresses

Posted on 2006-03-24
Last Modified: 2009-01-26
I took a look at my virtual SMTP server running on Exchange 2003 /w SP2 and noticed a lot of strange email domain's that are attempting to go out. They seem stuck and say retry.

Is someone trying to use Exchange to spam messages out and they simply get stuck in the queue?

How do I check this to make sure no one can relay out and what is causing all these messages to be stuck in the queue?


Question by:john_s99
    LVL 24

    Expert Comment

    It could be that, or it could be NDR messages to a spammer that had been sending messages to users (or non-existent users) in your domain.
    LVL 24

    Expert Comment

    Sembee's site ( has a lot of good information on anti-spam measures.

    Author Comment

    I also notice on a different server, running Exchange 2003 SP2 that valid messages get stuck in the queue.

    If I try to stop the smtp server, the smtp service gets hung, i.e. it says stopping and then I have to reboot the server, once I do that all the messages that were in the queue get delivered ok.

    Any idea what would be causing the smtp service to hang? Also, when the server restarts the smtp service doesn't start automatically, even thou in the services it is listed as automatic.

    I then have to start the smtp service manually then the messages get delivered.

    Any idea's on this one?
    LVL 74

    Accepted Solution

    The specific article to get this done is here:

    Usually this is caused by NDR's trying to go to non-existant addresses... too many of them and you're stuck.
    Generally caused by a spammer using your domain name in the "Reply to" field... and there's not much you can do about that.

    LVL 24

    Assisted Solution

    Regarding your second question...I have heard that sometimes these connections trying to return the NDRs can choke up the SMTP virtual server.  I haven't ever been privvy to the problem sticking the queue, but generally delete these messages (without NDR).  It may be that your AV is sticking the queue up as well, so make sure that you have the exclusions in place for \mailroot\vsi 1\queue and \pickup for the *.eml files.

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