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How to find messages that are looped with this message: "A local Loop was detected" RRS feed

  • Question

  • Hello,

    So I work for a university that has a central email routing service.  All campus mail comes in to that and then routes it to whatever the user has set as their forwarder.  IE.  I email   xyz@qqq.edu  it comes into our campus mail routing system and sees that xyz account goes to  ppp.qqq.edu, so it forwards it to xyz@ppp.qqq.edu.  The problem is, people remove mailboxes and doing remove the central mail forwarding.  So a loop is created.  I don't see anything in the event tracking logs that would differentiate it from any other message other than a really long messageinfo line.  In the queue viewer, I see it says 'A loop was detected".

    How can I search the message tracking logs and find the addresses that are looping so I can have them change the campus mail forwarding? 

    thanks,

    Peter

    Thursday, March 20, 2014 10:04 PM

Answers

  • If you have one of the NDRs you can find the corresponding event in the tracking logs. The SMTP status codes and text are part of the event. You probably won't be able to use the GUI to construct a query that specific, but you can export the events to a CSV and then use powershell to look for the events in the file using whatever filters you can construct.

    There a few different kinds of loops. One would be where the MX (or A) of the destination points pack to the server trying to send the message. Another is when a message is "ping-ponged" between two ,achiness and the number of "Received:" headers exceeds whatever value you have configured for your organization. I don't know if either of those are what you're experiencing.


    --- Rich Matheisen MCSE&I, Exchange MVP

    Friday, March 21, 2014 9:44 PM

All replies

  • Do the message eventually generate a NDR? You can look for the failures.

    If they're just sitting in a queue you can export the message to a file and examine the headers.


    --- Rich Matheisen MCSE&I, Exchange MVP

    Friday, March 21, 2014 2:53 AM
  • Thanks Rich,  Yeah I was hoping there was some field that would specify the loop.  I have a lots of other NDR's just from bad addresses in general, so I was wondering if there was a different way to identify the ones that NDR'ed because of the loop issue.

    I'll keep looking though. 

    Thanks

    Peter

    Friday, March 21, 2014 4:04 PM
  • If you have one of the NDRs you can find the corresponding event in the tracking logs. The SMTP status codes and text are part of the event. You probably won't be able to use the GUI to construct a query that specific, but you can export the events to a CSV and then use powershell to look for the events in the file using whatever filters you can construct.

    There a few different kinds of loops. One would be where the MX (or A) of the destination points pack to the server trying to send the message. Another is when a message is "ping-ponged" between two ,achiness and the number of "Received:" headers exceeds whatever value you have configured for your organization. I don't know if either of those are what you're experiencing.


    --- Rich Matheisen MCSE&I, Exchange MVP

    Friday, March 21, 2014 9:44 PM