DN Singh: > I had a doubt about concurrency. Can it be that there are multiple > connections to the destination? Although documentation suggests otherwise.
The logging shows that the connections in my real-life example are separated by 5 seconds. The logging also shows that the messages were submitted at the same time. At this point must I invite you to reproduce my two examples. If the two examples do not reproduce, then you must file a bugreport with the person who modified Postfix. Wietse