The
-f command-line switch causes
sendmail to take the address of the sender from
the command line rather than from the envelope or message header. The
-f switch is used by UUCP software and by mailing
list software. The form of the -f switch is:
-faddr
-f addr
Space between the -f and the
addr is optional. If
addr is missing,
sendmail prints the following error message and
ignores the -f switch:
sendmail: option requires an argument -- f
Multiple -f switches cause
sendmail to print the following error message
and exit:
More than one "from" person
The behavior of this switch varies depending on the version of
sendmail you are running.
Prior to V8 the uid of the user specifying the
-f switch must match one of the usernames given in
the T configuration command. If they do not match,
sendmail silently ignores the option and
determines the sender's address in the usual ways.
From V8.1 through V8.6 the T configuration command
was eliminated. If the -f or -r
switch was used, and if the p (privacy) option was
given authwarnings, sendmail
included an X-Authentication-Warning: header in
the mail message. That header warned that the identity of the sender
had changed.
Beginning with V8.7 sendmail, the
T was reintroduced, but in a different form (Section 10.8.1). First sendmail checks
to see whether the user specified by the -f is the
same as the login name of the user running
sendmail, as would be the case for
mh(1). If they are the same,
sendmail silently accepts the address. If they
differ, sendmail looks to see whether the login
name of the user running sendmail is in the
class $=t. If it is, sendmail
silently accepts the address. If not, sendmail
checks to see if authwarnings is set for the
PrivacyOptions option (PrivacyOptions). If it is, the following warning is logged
and included in the outgoing message:
X-Authentication-Warning: login set sender to new name using -f
An example of one use for the -f switch can be
seen in the previous section covering the -F
switch.
