Re: [cups] CUPS and IPP strangeness

--===============0580570683==
Content-type: text/plain; charset=us-ascii

Sorry, I got a bit confused in my reply. Yes my original complaint was
about PF0, and HP P2055dn, which is not especially a problem. It just
appeared to be the problem because I misinterpreted the log.

The actual problem is PF6, a Toshiba e-Studio 4540C. Please consider
that when decoding my earlier message (copied below).

>I wrote:
>
>>I'm managing a small network with about a dozen printers. Some are
>>unable to accept IPP and are configured to use JetDirect. All others
>>are configured with IPP.
>>
>>But one JetDirect printer in particular is having some strangeness.
>>The /etc/cups/printers.conf file contains these lines.
>>
>>   <Printer PF0>
>>   Info HP p2055dn
>>   DeviceURI socket://pf0
>>
>>But /var/log/cups/error_log contains lines like this one (wrapped here).
>>
>>   E [29/Jul/2025:22:03:18 -0700] Returning IPP client-error-bad-request
>>   for Send-Document (ipp://localhost:631/printers/PF0) from localhost
>>
>>That sure look to me like CUPS is trying to send IPP traffic to this
>>printer. That certainly won't work, port 631 is not open on this printer.
>>I've restarted CUPS without effect. What can I do to fix this?
>
>Till Kamppeter answered:
>
>>No, CUPS is not sending IPP to the printer, CUPS' native language is also IPP
>.
>> 
>>It speaks IPP between CUPS dameons on clients and servers and clinet 
>>applications which print on a CUPS queue talk IPP to the CUPS daemon.
>>
>>The error is caused by some client application which wanted to print (or get 
>>infor about available printers), sending a somehow broken IPP request which i
>s
>> 
>>assigned to your printer's queue (client sends to the CUPS queue's URI 
>>ipp://localhost:631/printers/PF0) but CUPS is somehow not understanding the 
>>request's content, which causes the error.
>>
>>More information, especially a complete error_log in debug mode (run `cupsctl
> 
>>--debug-logging` to switch to debug mode), the application from which you wan
>t
>>ed 
>>to print and the file you wanted to print.
>
>Thanks. The debug log contains these lines:
>
>... [Job 645966] Getting supported attributes...
>... [Job 645966] Unable to get printer status (Bad Request)!
>
>This agrees with tcpdump which shows:
>
>  IPP Request (Get-Printer-Attributes)
>  HTTP 1.1 400 Bad Request (text/html)
>
>This is a fairly recent and extremely capable printer with tons of
>options. I suspect the issue is that the old version of CUPS on this
>system is sending something the printer doesn't understand. Here's
>the content of the attribute request as decoded by tcpdump.
>
>  Internet Printing Protocol
>       version: 1.0
>       operation-id: Get-Printer-Attributes (0x000b)
>       request-id: 1
>       operation-attributes-tag
>              attributes-charset (charset): 'utf-8'
>                     name: attributes-charset
>                     charset value: utf-8
>              attributes-natural-language (naturalLanguage): 'en-us'
>                     name: attributes-natural-language
>                     naturalLanguage value: en-us
>              printer-uri (uri): 'ipp://pf6:631/ipp/'
>                     name: printer-uri
>                     uri value: ipp://pf6:631/ipp/
>              […]requested-attributes (1setOf keyword): 
>'com.apple.print.recoverable-message','copies-supported','document-format-supp
>orted','marker-colors'
>,'marker-high-levels','marker-levels','marker-low-levels','marker-message','ma
>rker-names','mar
>                     name: requested-attributes
>                     keyword value: com.apple.print.recoverable-message
>                     keyword value: copies-supported
>                     keyword value: document-format-supported
>                     keyword value: marker-colors
>                     keyword value: marker-high-levels
>                     keyword value: marker-levels
>                     keyword value: marker-low-levels
>                     keyword value: marker-message
>                     keyword value: marker-names
>                     keyword value: marker-types
>                     keyword value: printer-is-accepting-jobs
>                     keyword value: printer-state
>                     keyword value: printer-state-message
>                     keyword value: printer-state-reasons
>  end-of-attributes-tag
-- 
         Dave Close, Compata, Irvine CA       +1 714 434 7359
       dave-AvszEi/[email protected]              [email protected]
  "If people did not sometimes do silly things,
   nothing intelligent would ever get done." -- Ludwig Wittgenstein



--===============0580570683==
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: base64
Content-Disposition: inline

X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KY3VwcyBtYWls
aW5nIGxpc3QKY3Vwc0BjdXBzLm9yZwpodHRwczovL2xpc3RzLmN1cHMub3JnL21haWxtYW4vbGlz
dGluZm8vY3Vwcwo=

--===============0580570683==--