Log from MTA option

Transaction logging MTA options:  (0-3)
(New in MS 8.1.0.2.) The  MTA option controls whether or not the address in the header From: field is extracted and used in transaction log entries and mapping probles. The option defaults to 0, meaning the field is not extract by default. Setting bit 0 (value 1) causes from address to be logged just prior to any smartsend string. The XML/JSON attribute name in XML/JSON format logs (  set to 4 or 5-6, respectively) is " ". Setting bit 1 (value 2) causes from address to be included in the  mapping table  probe, again just prior to the smartsend string.

Normally the  attribute only appears in XML or JSON format logs if there is a from address to log. However, setting bit 2 (value 4) will cause the attribute to appear unconditionally.

See also:
 * MTA transaction logging
 * Transaction logging MTA options