Novell LINUX ENTERPRISE SERVER 10 SP2 - INSTALLATION AND ADMINISTRATION Installation Manual page 478

check all possible ports, use the command nmap
-p from_port-to_port IP-address. This may take some time. For further
information, refer to the man page of nmap.
Enter a command like
echo -en "\rHello\r\f" | netcat -w 1 IP-address port
cat file | netcat -w 1 IP-address port
to send character strings or files directly to the respective port to test if the printer
can be addressed on this port.
23.9.5 Defective Printouts without Error
For the print system, the print job is completed when the CUPS back-end completes
the data transfer to the recipient (printer). If the further processing on the recipient fails,
for example, if the printer is not able to print the printer-specific data, the print system
does not notice this. If the printer is not able to print the printer-specific data, select a
different PPD file that is more suitable for the printer.
23.9.6 Disabled Queues
If the data transfer to the recipient fails entirely after several attempts, the CUPS back-
end, such as USB or socket, reports an error to the print system (to cupsd). The
back-end decides whether and how many attempts make sense until the data transfer
is reported as impossible. Because further attempts would be in vain, cupsd disables
printing for the respective queue. After eliminating the cause of the problem, the system
administrator must reenable printing with the command /usr/bin/enable.
23.9.7 CUPS Browsing: Deleting Print Jobs
If a CUPS network server broadcasts its queues to the client hosts via browsing and a
suitable local cupsd is active on the client hosts, the client cupsd accepts print jobs
from applications and forwards them to the cupsd on the server. When cupsd accepts
a print job, it is assigned a new job number. Therefore, the job number on the client
host is different from the job number on the server. Because a print job is usually for-
460 Installation and Administration
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