The special address
<> is used as the envelope sender when
sendmail bounces a mail message. This address is
intended to prevent bounced messages from bouncing. Unfortunately,
not all configuration files properly handle this form of sender
address. The stock SunOS configuration files prior to Solaris 2.3,
for example, caused sendmail to enter an endless
loop when processing <>. Also, some UUCP
implementations get confused when they are executed with command-line
arguments of:
-f <>
As an interim measure, until all programs learn to correctly handle
the <> address, you can use the
F=g delivery agent flag to suppress that address
for selected delivery agents. If the F=g delivery
agent flag is set for a delivery agent, it uses the value of
$g ($g) in place of the
<>, where $g contains
$n (usually MAILER-DAEMON, $n) with an @ and the local
domain name appended.
