Error conditions, also known as event logging
For the most part, Messaging Server logging provides operational data. This operational data contains information such as: the date and time a message entered the system; the sender and recipient of the message; when the message was written to disk; and at a later point in time, when the message was removed from disk and inserted into user’s mailbox.
However, Messaging Server logging does also provide some event logging data. To obtain event logging data, you need to pull together multiple items from different log files. You could then use a unique constant, such as message ID, to search and correlate the lifecycle of a message as it passed from point to point through the system.