I have an Exchange 2013 CU1 and Exchange 2007 SP3 server in the same Exchange environment, and have recently migrated external mailflow to the 2013 box. I have noticed that I get periodic delays in inbound mail several times a day.
External mail flow stops for around 15-20 minutes, then springs back into life.
Looking through the event logs I can see multiple informational event 16022's from the ExchangeTransport / Front End services, indicating that various configuration updates have successfully completed at about the time mail flow stops (even though there have been no administrator config changes made).
About 15 minutes later I then see an event 1000 indicating the Transport service is trying to start (even though I can find no sign of it stopping), followed by a load of ESE events starting up the queues, and then mail flow starts again.
I have no idea what is causing this - any suggestions?
Many thanks