This program is responsible for coordinating the transmission of
messages that have been queued by
It uses a variety of protocol modules to deliver the messages from the
queue to remote "smart" servers.
When the program starts, the queue is scanned to build a list of
messages to send.
The queue is rescanned when either the trigger is pulled, or after
seconds have elapsed after the last failed delivery.
When there are no messages in the queue, nullmailer does no rescanning
until the trigger is pulled.
Pulling the trigger consists of opening up the trigger named pipe and
writing a single byte to it, which causes this program to be awakened
(if it's not already processing the queue).
This procedure is done by
to ensure that messages are delivered immediately.
Delivery of messages consists of reading the list of remote servers and
then trying to deliver the messages to these servers as follows.
For each remote in the list, the named protocol handler is executed once
for each message remaining in the queue.
If the protocol handler succeeds, the message is removed from the queue
and processing continues with the next message.
If it fails, the remote is skipped and processing of the remaing
messages continues with the next remote.
When all the remotes have been tried,
sleeps for a number of seconds specified by
before retrying sending the contents of the queue.
Fork into the background, implies --syslog.
Use syslog for error and log messages.
With --daemon, syslog will be used exclusively, without --daemon,
syslog will be used additionally.
All the control files are reread each time the queue is run.
Sets the environment variable
which is used by the SMTP protocol module to set the parameter given to
command. Defaults to the value of the
The number of seconds to pause between successive queue runs when
there are messages in the queue (defaults to
If this is set to
nullmailer-send will exit immediately after going through the queue once
This file contains a list of remote servers to which to send each
Each line of this file contains a remote host name or address followed
by an optional protocol string, separated by white space.
The protocol name defaults to
and may be followed by command-line arguments for that module.
For example, to connect to port 2525 on your SMTP smart host,
which also requires SMTP authentication, use:
Blank lines and lines starting with a pound are ignored.
The number of seconds to wait for a remote module listed above to
complete sending a message before killing it and trying again (defaults
If this is set to
will wait forever for messages to complete sending.