config_directory (see 'postconf -d' output)
The default location of the Postfix main.cf and master.cf configuration files.
daemon_directory (see 'postconf -d' output)
The directory with Postfix support programs and daemon programs.
import_environment (see 'postconf -d' output)
The list of environment parameters that a Postfix process will import from a non-Postfix parent process.
multi_instance_directories (empty)
An optional list of non-default Postfix configuration directories; these directories belong to additional Postfix instances that share the Postfix executable files and documentation with the default Postfix instance, and that are started, stopped, etc., together with the default Postfix instance.
multi_instance_group (empty)
The optional instance group name of this Postfix instance.
multi_instance_name (empty)
The optional instance name of this Postfix instance.
multi_instance_enable (no)
Allow this Postfix instance to be started, stopped, etc., by a multi-instance manager.
postmulti_start_commands (start)
The postfix(1) commands that the postmulti(1) instance manager treats as "start" commands.
postmulti_stop_commands (see 'postconf -d' output)
The postfix(1) commands that the postmulti(1) instance manager treats as "stop" commands.
postmulti_control_commands (reload flush)
The postfix(1) commands that the postmulti(1) instance manager treats as "control" commands, that operate on running instances.
syslog_facility (mail)
The syslog facility of Postfix logging.
syslog_name (see 'postconf -d' output)
The mail system name that is prepended to the process name in syslog records, so that "smtpd" becomes, for example, "postfix/smtpd".