XCON: Application Protocol Data Unit (APDU) Logs (BF0.LOG)

• Microsoft Exchange Server, version 4.0
• Microsoft Exchange Server, version 5.0

SUMMARY

Application Protocol Data Unit (APDU) text logs are binary representations of communication among Microsoft Exchange Message Transfer Agents (MTAs) in different Sites and between MTA and client applications within a Site. The log includes the fully-encoded ASN.1 envelope. This is useful for verifying when messages from remote MTAs are bad or invalidly formatted.

MORE INFORMATION

Increasing Diagnostic Logging levels to Medium or higher for both the MTA's APDU and X.400 Service categories will generate BF*.LOG files in the exchsrvr\MTADATA directory. The current log is always named BF0.LOG. Prior logs are named BF#.LOG with the # increasing with the age of the log. When a log reaches 5 megabytes in size it is renamed and a new log is begun.

NOTE: There is no difference between Medium and Maximum for the APDU category. However, in addition to its influence on APDU logs, the diagnostics logging level of the X.400 Service category determines which X.400 events are written to event logs.

APDU logs can be instrumental in diagnosing problems with the MTA. However, they are valuable only to those familiar with ASCII translations of X.400 protocol. These logs can grow quite large very quickly and cause performance on the Server to suffer.

An ASN.1 Parser can be used to decode the data in a BF0.LOG.

If the logging levels of both X.400 Service and APDU are set to Minimum, the first four events in the table below will be written to the Event Logs. If the logging levels of both categories are set to Medium or greater, all six events will be logged and the APDU text logs will be generated as well.

Event #  Description                                Logging Level

200      Bad APDU transferred in from another MTA   Minimum
220      Bad APDU submitted to this MTA             Minimum
269      APDU delivery failed temporarily           Minimum
270      APDU delivery failed permanently           Minimum
271      APDU sent                                  Medium
271      APDU received                              Medium