Name
M line
Synopsis
When a mail message is placed into the
queue because of an error during the delivery attempt, the nature of
that error is stored in the M
line of the
qf
file. The error is usually prefixed with
Deferred
:
Deferred: reason
Delivery can be deferred until a later queue run because of a
temporary lack of services. For example, the
reason
might be “remote
host is down.”
The form of the qf
file M
line
is:
Mmsg
The M
must begin the line. It is immediately
followed by the msg
with no intervening
space. The text of msg
is everything up to
the end of the line. The msg
created by
sendmail can include the word
Deferred
:, followed by a reason. The
envelope-specific M
line should appear before the
S
line.
Beginning with V8.12, each recipient also has an M
line preceding its R
line.
If the msg
is missing,
sendmail simply prints a blank line rather than
a reason when showing the queue with mailq or
the -bp
command-line switch. If the
M
line is missing entirely,
sendmail prints nothing.
The maximum number of characters in msg
is
defined by MAXLINE in conf.h (MAX...). Prior to V8.12, there could be only one
M
line in a qf
file.
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