Section: Maintenance Commands (8)
nullmailer-send - Send queued messages
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.
You can start delivery by hand from the command line like this:
echo 1 > trigger
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 the protocol handler reports a permanent failure
or the message has been in the queue longer than
the message is moved into the
queue and a bounce message is generated with
If any messages remain in the queue, 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.
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 maximum time to pause between successive queue runs, in seconds.
Defaults to 24 hours
The minimum time to pause between successive queue runs
when there are messages in the queue, in seconds.
Defaults to 1 minute
Each time this timeout is reached, the timeout is doubled to a maximum
After new messages are injected, the timeout is reset.
If this is set to
nullmailer-send will exit immediately after going through the queue once
The maximum time a message is allowed to live in the queue before being
considered permanently failed, in seconds. Defaults to 7 days
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 additional options for that module.
See the "PROTOCOL OPTIONS" section for a list of the available options.
The options may optionally be prefixed by
but this is not required.
The line is parsed according to standard shell quoting rules.
For example, to connect to port 2525 on your SMTP smart host,
which also requires SMTP authentication, and initiate TLS with
smarthost.dom smtp port=2525 starttls user=user pass='my pass phrase'
Blank lines and lines starting with a pound (#) are ignored.
The time to wait for a remote module listed above to complete sending a
message before killing it and trying again, in seconds.
Defaults to 1 hour
If this is set to
will wait forever for messages to complete sending.
Set an alternate port number to connect to on the remote host. For example, SMTP may use
for the alternate SMTP "submission" port.
Set the SMTP authentication user name.
Set the SMTP authentication password.
Set the source address for connections to the remote host.
Force SMTP "AUTH LOGIN" mode instead of auto-detecting.
Connect using TLS.
This will automatically switch the default port to
Alias for the
option for compatibility.
command to initiate a TLS session.
Set the filename for a TLS client certificate to send to the server.
Set the filename for the private key for a TLS client certificate.
Defaults to the same file name as
Set the TLS certificate authority trust filename. Defaults to
Set the TLS certificate revocation list filename.
Specify that TLS X.509 files above are in DER format instead of PEM.
Don't abort a TLS connection if the server certificate fails validation.
Use this only if you know the server uses an invalid certificate.
The failed message queue.
The outgoing message queue.
A trigger file to cause immediate delivery.
The configuration directory.
The protocol program directory.