Delivery Agent Invocation
When built from source as outlined previously, the procmail command itself is installed in /usr/local/bin. Most Linux distributions install the procmail binary in /usr/bin/procmail. In the next sections, we show how to invoke procmail under the covered MTAs, which include Sendmail, Postfix, and qmail.
Sendmail can be configured to use procmail as the delivery agent. Procmail is enabled by a FEATURE setting in the Sendmail configuration file, such as $SRC/cf/sendmail.mc.
If procmail is not in the standard place, you have two choices. Perhaps the simplest way to tell Sendmail where to find procmail is use a second argument to FEATURE to tell it where it is: