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Enable secure ports for CUPS printing Network
In Panther, I suddenly lost the ability to print to my school printers over lpr/lpd. We traced the problem: Apple had changed the port from which the print job was sent from a low-numbered "trusted" port to a high-numbered one. The print server would reject this port (error #32; data file refused) as insecure. The solution is as follows. After creating your printer, do this:

 % cd /etc/cups
 % sudo emacs printers.conf
There will be a line that looks something like this:

lpd://server.domain/printqname
where server.domain is the computer the printer queue is on, and printqname is the name of the printer queue. You must change this line to look like this:

lpd://server.domain/printqname?reserve=on
Save the changes and quit the editor. This will enable the correct port behaviour. Then you need to restart cupsd. in a shell, do this:

 % ps -auwx | grep cupsd
 root      348   1.1  0.1    29016   1372  ??  Ss   Thu03PM   0:26.90 /usr/sbin/cupsd
 markian  5144   0.0  0.0     8860      8 std  R+    2:17PM   0:00.00 grep cupsd
 % sudo kill -HUP 348
Note that 348 is the cupsd (cups daemon) process id (in this example). You should now be able to successfully print. Special thanks to Carol Smith at the University of Alberta for being invaluable in solving this problem.
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Enable secure ports for CUPS printing
Authored by: tsugaru on Nov 27, '03 03:29:28AM

University of Alberta rocks!!

Anthony Vu
School of Business Student



[ Reply to This | # ]
Enable secure ports for CUPS printing
Authored by: BMarsh on Nov 27, '03 11:49:58AM

I read about this somewhere else, Apple hadn't specifically changed this behaviour... they used a newer version of CUPS, and in CUPS this behaviour of LPD had changed... due to a few limits of the old way of working...

by using previously "trusted" or low-numbered ports (Reserved) LPD was limited to 11 printers, this behaviour I believe is actually changed in newer LPD implimentations in general... although they really should have come up with a method of doing both systems while people transition.

Just though I'd provide some background... if I can find the URL from the person who helps maintain CUPS commenting on this, I will be sure to add that to the comments here.



[ Reply to This | # ]
There is a much easier way...
Authored by: cmh on Nov 30, '03 01:51:35PM
Although this editing trick works for existing printers, if you want to create a new printer, you can do it without accessing the terminal.

See here for instructions.

[ Reply to This | # ]

Enable secure ports for CUPS printing
Authored by: dknightd on Mar 22, '04 07:55:52PM

Ah, this might also explain why lpd serving seems to have been broken by upgrading to 10.3.3 (from 10.3.2). Does anybody know how to determin which port lpd listens to, and change that back the the value it used to be?



[ Reply to This | # ]
Enable secure ports for CUPS printing
Authored by: dknightd on Mar 22, '04 08:01:54PM

Nevermind. It seems that cupsd is still listening on port 631 (as it should).

I'm not sure shy upgrading to 10.3.3 stopped IP printer serving from working - does anybody else?



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