RFC2822
requires that each email message have a unique worldwide identifier
associated with it. That identifier is listed with the
Message-ID: header (Message-ID:)
and often looks something like this:
Message-Id: <200212131533.dAPFX1o01876@here.us.edu>
The information inside, and including, the angle brackets is the
message identifier. That identifier is what is listed with the
msgid= syslog equate:
msgid=<200212131533.dAPFX1o01876@here.us.edu>
If a mail message arrives without a Message-ID:
header, and if your configuration file correctly includes a
definition for that header, a new identifier will be created and
listed with msgid=. If a
Message-ID: header is absent, and if your
configuration file incorrectly excludes a definition for that header,
the msgid= syslog equate will
be excluded from the syslog report.
The msgid= syslog equate is
shown only for sender records.
