User`s guide

2-48
Guide to Printers and Printing
The following sections discuss how to configure, use and manage a remote printing
environment:
• The rembak Program
• The lpd daemon
rembak Program
The local queue set up to serve remote print requests must be configured to use rembak,
the remote print backend command. When you set up the queue, the system prompts for a
backend program path name. The entry at this prompt tells the qdaemon command which
backend program to use to process print requests. To set up a queue to handle remote print
requests, type /usr/lpd/rembak.
The rembak command also processes status requests, job cancel requests, and requests
to kill a remote queuing system. Status requests such as qchk –A or lpstat query the status
of local print queues and devices by analyzing the qconfig file and the local print spooling
subsystem status files.
In a remote print environment, the qchk –A and lpstat commands use the rembak program
to request queue status information from the print servers. The output of a queue status
command shows two entries for each remote queue. The first entry is the status of the local
queue to which remote jobs are sent. The second entry shows the status of the queue on
the remote print server where the jobs are printed. In the following example, the queue
name rq was used for both the queue on the local system and the queue on the remote
print server:
Queue Dev Status Job Files User PP % Blks Cp
––––– ––– –––––– ––– ––––––––––––––– –––––––––– ––– –– –––– ––
Iago Iago RUNNING 284 mileaf ann@arctur 15 13 1 1
Pro asc READY
bsh bshde READY
ps ps READY
rq rqd READY
rq ps1 RUNNING 297 .deskprint/dsktop sarah@alde 60 22 1 1
QUEUED 298 .deskprint/howtol sarah@alde 60 1 2
As the preceding example shows, any print jobs currently running or queued show up 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, use the Web-based System Manager wsm
printers fast path 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. Once 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.