spawn [generic Postfix daemon options] command_attributes...
The spawn(8) daemon provides the Postfix equivalent of inetd. It listens on a port as specified in the Postfix master.cf file and spawns an external command whenever a connection is established. The connection can be made over local IPC (such as UNIX-domain sockets) or over non-local IPC (such as TCP sockets). The command's standard input, output and error streams are connected directly to the communication endpoint.
This daemon expects to be run from the master(8) process manager.
The external command attributes are given in the master.cf file at the end of a service definition. The syntax is as follows:
In order to enforce standard Postfix process resource controls, the spawn(8) daemon runs only one external command at a time. As such, it presents a noticeable overhead by wasting precious process resources. The spawn(8) daemon is expected to be replaced by a more structural solution.
The spawn(8) daemon reports abnormal child exits. Problems are logged to syslogd(8).
This program needs root privilege in order to execute external commands as the specified user. It is therefore security sensitive. However the spawn(8) daemon does not talk to the external command and thus is not vulnerable to data-driven attacks.
Changes to main.cf are picked up automatically as spawn(8) processes run for only a limited amount of time. Use the command "postfix reload" to speed up a change.
The text below provides only a parameter summary. See postconf(5) for more details including examples.
In the text below, transport is the first field of the entry in the master.cf file.
Postfix 2.4 and later support a suffix that specifies the time unit: s (seconds), m (minutes), h (hours), d (days), w (weeks). The default time unit is seconds.
config_directory (see 'postconf -d' output)
postconf(5), configuration parameters master(8), process manager syslogd(8), system logging
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Wietse Venema IBM T.J. Watson Research P.O. Box 704 Yorktown Heights, NY 10598, USA