If sendmail is run
with a -f command-line argument (-f) and if the F=f delivery
agent flag is specified, the A= for this delivery
agent will have the two additional arguments -f
and $g inserted between its
argv[0] and argv[1]. For
example, if sendmail is run as:
/usr/lib/sendmail -f jim host!bill
and if the delivery agent for sending to host is
defined as:
Muucp, P=/bin/uux, F=fmsDFMhuU, S=13, R=23, A=uux - -r $h!rmail ($u)
the f in F=fmsDFhuU causes the
A= of:
A=uux - -r $h@rmail ($u)
to be rewritten as:
A=uux -f $g - -r $h@rmail ($u)
Here, $g is jim from the
original command line (but rewritten to be a return address relative
to the recipient). The original -f argument
jim is first rewritten by the
canonify rule set 3, the rule set 1, and then the
final rule set 4. The result of those rewrites is
placed into $f. The $f
sendmail macro is rewritten by the
canonify rule set 3, the rule set 1, the
S= rule set, and then the final
rule set 4, and the result is placed into $g.
($f and $g are described in
$g.)
Note that the F=f and the F=r
delivery agent flags are very similar and easily confused.
