Novell LINUX ENTERPRISE SERVER 10 - INSTALLATION AND ADMINISTRATION 11-05-2007 Installation Manual page 475

This output indicates that the printer connected to the print server box can be ad-
dressed via TCP socket on port 9100. By default, nmap only checks a number of
commonly known ports listed in /usr/share/nmap/nmap-services. To
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
Message
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.
Printer Operation 457