Log reason MTA option

Transaction logging MTA options:  (0-3)
(New in MS 6.3.) The  MTA option controls whether message rejection reason text is included in  MTA message transaction log entries and    mapping probes that correspond to a message rejection ("R" or "K" records).

Setting bit 0/value 1 enables such logging; clearing the bit disables such logging. As of MS 6.3P1, enabling XML format ( set to 4) causes the default for   to be 1; with any other format, the default is 0, as in previous versions.

If logging is enabled, the reason text string will be logged just after the filter field (  set to 1) and just before the SMTP delivery status  (  SMTP diagnostic)  field. In XML or JSON format (  set to 4 or 5, respectively),  the reason logging, if enabled, appears as the   attribute.

Normally the  attribute only appears in XML or JSON format logs if there is reason information to log. As of MS 8.0.2.3, setting bit 2 (value 4) will cause the attribute to appear unconditionally.

New in 7.0-3.01, bit 1 (value 2), if set, causes reason information to be included in   mapping probes.

See also:
 * Transaction logging MTA options
 * MTA transaction logging
 * log_format MTA Option
 * Triggering effects from transaction logging with LOG_ACTION
 * log_filter MTA Option
 * log_diagnostics MTA Option