Specifications

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Printing Administration
As the preceding example shows, any print jobs currently running or queued are displayed
in the remote print server entry for the queue.
The rembak program also sends requests to cancel print jobs to the remote print servers.
Each print job is assigned a number. As shown in the previous example, print queue status
requests display the job numbers for currently queued or running print requests. To cancel a
job on a remote queue, use the same commands used to cancel local print jobs. For
example, to cancel job 298 from the queue rq, you can use Web–based System Manager
(enter wsm and then select Printers ) or one of the following commands:
qcan –Prq –x298
OR
lprm –Prq 298
lpd daemon
Although local and remote print jobs are submitted with the same commands, they are
processed differently. After a print job has been transmitted to a remote host, it is no longer
managed by the local print spooling subsystem.
The lpd daemon is part of the TCP/IP system group. Any host on a TCP/IP network can run
the lpd daemon, and any host can send print requests to any other host on the network (if
the host is currently running lpd). As a security measure, the lpd daemon forks a child
process that checks each remote print request against two database files: the
/etc/hosts.equiv file and the /etc/hosts.lpd file. If the name of the host submitting the print
request is not in the /etc/hosts.lpd file, the print request is rejected.
Note: The /etc/hosts.equiv file defines which computers on a network are allowed to
execute certain commands on a local host without supplying a password. The
/etc/hosts.lpd file defines which computers on a network are allowed to execute print
commands on a local host without supplying a password.
The lpd daemon on the remote print server monitors port 515 for print requests. When the
lpd daemon receives a print request from a valid host, it places the request in the specified
queue. The lpd daemon places files specified in print requests in the directory
/var/spool/lpd. The print request is then managed by the qdaemon and the appropriate
backend (usually piobe) on the remote server.
The /etc/locks/lpd file contains the process ID of the currently running instance of the lpd
daemon. If a machine running the lpd daemon becomes inoperable, the ID for the lpd
daemon may have to be removed before the system is restarted. The error messages lpd:
lock file or duplicate daemon indicate that the ID must be removed.
Controlling the lpd daemon
Controlling the lpd daemon includes starting and stopping the lpd subsystem and changing
the characteristics of the lpd subsystem. You can use Web–based System Manager (enter
wsm, and then select Printers ), or use the SMIT or System Resource Controller (SRC)
commands to control the lpd daemon.
There are three ways to start the lpd daemon. If it is not currently running, you can start the
daemon at any time. You also have the option of having the lpd daemon start at system
restart or to have it start both at the current time and at system restart. The same options
are available to stop the lpd daemon: stop now, stop at system restart, or stop both now
and at system restart. You can run the lpd daemon with DEBUG, with SYSLOG, with both
DEBUG and SYSLOG, or with neither.
To control the lpd daemon with Web–based System Manager, enter wsm and select
Printers, and then select the desired options from the Printer Queues window menus. To
control the lpd daemon with SMIT, enter smit lpd, and then select the desired options
from the SMIT menus. To control the lpd daemon with the SRC, use the following SRC
commands: