[cups.general] Printing to plp-System

Helge Blischke h.blischke at srz.de
Tue Apr 10 07:07:27 PDT 2007


Daniel Spannbauer wrote:
> 
> Kurt Pfeifle schrieb:
> 
>>>Helge Blischke schrieb:
>>>    
>>>
>>>>Daniel Spannbauer wrote:
>>>>
>>>>      
>>>>
>>>>>Ok, Good to know. Otherwise, can I print to a printe rattach to a Server
>>>>>by the old LPD-System (In SUSE called lprng-old)?
>>>>>
>>>>>Regards
>>>>>
>>>>>Daniel
>>>>>
>>>>>
>>>>>Helge Blischke schrieb:
>>>>>
>>>>>
>>>>>        
>>>>>
>>>>>>Daniel Spannbauer wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>          
>>>>>>
>>>>>>>Hallo,
>>>>>>>
>>>>>>>wie have a System which is growing throu the time, but the
>>>>>>>Printing-System is still the old PLP-System.
>>>>>>>
>>>>>>>Now we are planing to switch to newer Linux-VErsions so we also have to
>>>>>>>update the Printing-System to Cups.
>>>>>>>But this is going step by step so we have to print from the Cups-System
>>>>>>>to some old Machines with PLP installed.
>>>>>>>
>>>>>>>Is Cups able to print to a Printer which is attached by the plp-System?
>>>>>>>
>>>>>>>Regards
>>>>>>>
>>>>>>>Daniel Spannbauer
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>            
>>>>>>
>>>>>>If printing to plp printers using the lpd backend does not work,
>>>>>>let me know, I have an experimental PLP backend (a Perl script)
>>>>>>that works with a quite old PLP installation from about d dozen years
>>>>>>ago but may easily be modified to your needs.
>>>>>>
>>>>>>Helge
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>          
>>>>
>>>>Yes, that brobably will work, but, as the LPD protocol is hardly
>>>>treated as a standard,there is a possibility that this will not
>>>>work. Use the lpd backend.
>>>>
>>>>Helge
>>>>
>>>>
>>>>      
>>>
>>>Ok, as I'm a dumb User I use the SuSE-Toy called Yast. Choose the
>>>Printing over Network, to a LPD-Server. I choose my Printer (here a
>>>Postscript-Level1-Printer),
>>>set the Remote-Server an the Printer-Name on the Remoteserver und try to
>>>print a Test-Page. On the Cups-Server there is no Error, but in the
>>>Messages of the LPD-Server I found the following:
>>>
>>>Apr 10 13:51:49 b-fs /usr/uti/lib/lpd[500]: From_host: from port 51227, max is 1023
>>>Apr 10 13:51:49 b-fs /usr/uti/lib/lpd[500]: lpd: From_host failed - No child processes
>>>
>>>Whats the Problem on the LPR-Side?
>>>    
>>
>>The "LPD RFC" 1179 asks for the LPD client to use as source ports only 721-731.
>>
>>This makes printing possibly very slow (many small jobs may use up all 11 allowed ports and it will need the TCP timeout before one of these ports is free to use again).
>>
>>Therefor, many LPD clients do use non-standard source ports too, in the hope that the LPD server silently accepts these (Microsoft's ServicePack 3 for Windows NT introduced this practice for the broad masses). The CUPS lpd:// backend does the same by default.
>>
>>However, you can force CUPS to limit itself to the "standard" LPD source ports when printing to a specific printer by adding a special parameter to the device URI:
>>
>>  lpadmin -p plpprinter -v lpd://plpserver/plpprintqueuename?reserve=rfc1179
>>
>>
>>See also http://www.cups.org/documentation.php/network.html#LPD for more options.
>>
>>  
>>
>>>In The Cups-Messages on the Cups-Server theres the Message "Started
>>>backend /usr/lib/cups/backend/lpd", so I think that the LPD-Backend
>>>is used.
>>>    
>>
>>Yes, but it uses as source port for its connections ports above 1024 which PLP does not seem to like.
>>
>>Cheers,
>>Kurt
>>
>>--
>>Kurt Pfeifle
>>System & Network Printing Consultant -- Linux/Unix/Windows/Samba/CUPS
>>Infotec Deutschland GmbH - A RICOH Company ........ Stuttgart/Germany
>>_______________________________________________
>>cups mailing list
>>cups at easysw.com
>>http://lists.easysw.com/mailman/listinfo/cups
>>
>>
>>  
> 
> 
> 
> Ok, Thank you.
> 
> Now in the /etc/cups/printers.conf there is an entry like:
> 
> DeviceURI lpd://b-fs/copy_b?reserve=rfc1179
> 
> 
> But the error on the LPD-Server-Side is still the same:
> 
> Apr 10 15:48:43 b-fs /usr/uti/lib/lpd[500]: From_host: from port 44263,
> max is 1023
> Apr 10 15:48:43 b-fs /usr/uti/lib/lpd[500]: lpd: From_host failed - No
> child processes
> 
> Regards
> 
> Daniel
> 
> 
> 
> 
> 
> 

I don't remember if you told the CUPS version you use. But anyway,
try "reserve=yes" instead of "reserve=rfc1179", and make sure the backend
is running as root (in CUPS 1.2.x, you must set the backend's permissions accordingly).

(Originally, reserve={yes|on|true} caused the backend to use only
port numbers from 721 to 732 (including), but starting with some
(don't remember which) version this has been extended to use
any reserved port (< 1024), and the more restricted range as mentioned above
defined by the "rfc1179").

Helge


-- 
Helge Blischke
Softwareentwicklung

H.Blischke at acm.org




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