Name
F=l (lowercase L)
Synopsis
The F=l
delivery
agent flag tells sendmail that this delivery
agent will be performing final delivery (usually on the local
machine). This notification affects
sendmail’s behavior in five
ways.
First, it enables the DSN notify-on-success mechanism.[32] That is, if the message were received via SMTP with the envelope:
RCPT To: <user@here.us.edu> NOTIFY=SUCCESS
or via the command line with a -Nsuccess
command-line switch, sendmail (upon final local
delivery) sends back to the original sender an email message
acknowledging receipt. This mechanism should be used sparingly.
Second, the F=l
delivery agent flag allows
sendmail to ignore any host part of the triple
returned by the parse
rule set 0. Ordinarily, the
$@
operator must appear in the RHS for all
delivery agents selected. If no host is selected by
$@
, sendmail prints this
error and bounces the message:
554 5.3.5 buildaddr: no host
But because the host is not always needed for final delivery, the
presence of the F=l
delivery agent flag tells
sendmail to silently ignore a missing host part.
Third, the F=l
delivery agent flag influences how
undeliverable mail will be handled. When the
ErrorMode
option (ErrorMode) is
q
(quiet), such mail is usually reported in the
sendmail program’s
exit(2) status (Section 15.5).
With the F=l
delivery agent flag set for the
envelope sender address, the undeliverable message will instead be
appended to ~/dead.letter for a local sender or mailed back for a remote sender. ...
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