delay in mail flow between exchange and ISA

Posted on 2012-08-29
Last Modified: 2012-09-11
Dear Experts,

I have an exchange 2007 server and a ISA server.  The ISA server has the necessary edge transport role installed and all has been working well for a few years now.

Lately, I have noticed that theres a delay in delivering incoming messages. In the queue viewer on the ISA server, I can see the messages in a queue which is bound for the exchange server. But I also notice a lot of strange undeliverable messages in there.

I have attached a screen dump for examples.  When I delete them, mail flows again.

I find it strange because its like the ISA box cant see the exchange server. DNS is functioning correctly.

Any ideas?

Question by:tech53
    LVL 22

    Expert Comment

    by:Matt V
    Are all the undeliverables coming from the same address or going to the same address?  I would start looking there.
    LVL 63

    Expert Comment

    by:Simon Butler (Sembee)
    The content in the queues are NDRs.
    Ensure that you are doing recipient validation on the server, so that it rejects email from non-valid recipients. It may well be that the server is delaying email because of the bogus email it has to process.


    Author Comment

    Thanks for helping. The emails have different recipients and senders. However simon has correctly identified them as NDRs - given the undeliverable subject.

    Simon, how can I enable recipient validation?

    Thanks again.
    LVL 63

    Accepted Solution


    That needs to be done on the Edge server. The agents should be already installed, so it just needs to be enabled.


    Author Comment

    thanks simon.  I've applied that and will monitor the queues.

    Author Comment


    That seems to have done the trick.

    You've helped me before on a few occasions. Many thanks for sharing your wisdom.

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