messages need to be treated equally. Messages that have failed often,
for example, tend to continue to fail. When
sendmail processes the messages in its queue, it
sorts them by priority and attempts to deliver those with the lowest
priority value first.
When a mail message is first placed into the queue, it is given an
initial priority calculated when it was first created (RecipientFactor), which is stored in the P
This number in the qf file is really a cost. The
lower it is, the more preferentially the message
is treated by sendmail. Each time the
qf file is read, the number in the
P line is incremented. The size of that increment
is set by the value of the RetryFactor option
(RetryFactor). If that option is negative, this
logic is inverted.
The form of the qf file P line
The P must begin the line. The
pri is a text representation of an integer
value. The pri must immediately follow the
P with no intervening space. The text in
pri is converted to an integer using the
C-library routine atol(3). That routine allows
pri to be represented in text as a signed
decimal number, an octal number, or a hexadecimal number.
pri is absent, the priority value used is
that of the configuration file RetryFactor option.
If the entire P line is absent, the priority value
begins as zero.
There should be only one P line in any
qf file. Multiple P lines cause
all but the last to be ignored.