Datasheet

“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 314 — #340
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80/tcp open http
515/tcp open printer
631/tcp open cups
9100/tcp open jetdirect
This output indicates that the printer connected to the print server
box can be addressed 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 hfrom_porti-hto_porti hIP-addressi. This
may take some time. For further information, refer to man 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.
13.7.5 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 process-
ing on the recipient fails (e.g., if the printer is not able to print the printer-
specific data), the print system will not notice this. If the printer is not able
to print the printer-specific data, select a different PPD file that is more suit-
able for the printer.
13.7.6 Disabled Queues
If the data transfer to the recipient fails entirely (normally a CUPS back-
end makes several attempts), the back-end reports an error to the print sys-
tem (more precisely: to cupsd). The back-end decides whether and how
many attempts make sense until the data transfer is reported as impos-
sible. As further attempts would be in vain, cupsd disables printing for
the respective queue (disable). After eliminating the cause of the prob-
lem, the system administrator must reenable printing with the command
/usr/bin/enable.
314 13.7. Printer Hardware