The MTA provides facilities for logging each message as it is enqueued and dequeued. The logging and nologging keywords control logging for messages on a per-channel basis. By default, the initial configuration turns on logging for all channels. You can disable logging for a particular channel by substituting the nologging keyword in the channel definition.
logheader overrides the LOG_HEADER MTA option on a per channel basis. A value of 0 (the default) disables message header logging. See the Option File in Sun Java System Messaging Server 6.3 Administration Reference for more information.
For more information about logging, see Chapter 25, Managing Logging.