[cups] Contents of cups Digest, Vol 58, Issue 21: "MacOS to Linux CUPS intermittent "

[Michael Sweet]

Keith,

The alternative is then either an Avahi bug *or* some sort of network glitch that is causing mDNSResponder to go off into the weeds for a bit on macOS.

You could try running Wireshark for a bit to see if something is happening (or not) on the network when the problem occurs - then at least you'll see which side is not communicating.


> On Sep 24, 2018, at 3:55 PM, Keith Oborn <keith.oborn at keble.oxon.org> wrote:
> 
> 
> The Pi (a 2B) hardware, OS and connectivity is definitely not the problem.
> 
> It is running two wired ethernets, and provides firewall, auth/caching DNS, mail server and other bits and pieces for my home network. All internet traffic goes through it. It doesn’t have a wifi adapter.
> 
> Basically, if anything fails on the Pi then we are offline, no DNS, no external connectivity—. So I’d have noticed!
> 
>> 
>> 
>> ------------------------------
>> 
>> Message: 3
>> Date: Mon, 24 Sep 2018 10:59:24 -0400
>> From: Michael Sweet <msweet at apple.com>
>> To: "The CUPS user discussion list." <cups at cups.org>
>> Subject: Re: [cups] MacOS to Linux CUPS intermittent "printer not
>> 	connected" problem
>> Message-ID: <7668FBE8-1053-4184-9382-23A971F16F2F at apple.com>
>> Content-Type: text/plain; charset=utf-8
>> 
>> Keith,
>> 
>> What version of Pi are you using?  Are you using the built-in Wi-Fi on your Pi?
>> 
>> I seem to remember seeing some reports of Wi-Fi issues with older Raspberry Pi's that required some settings changes to prevent the Wi-Fi adapter from going to sleep (or something along those lines).
>> 
>> 
>>> On Sep 24, 2018, at 4:16 AM, Keith Oborn <keith.oborn at keble.oxon.org> wrote:
>>> 
>>> I’m running CUPS on a Raspberry Pi, drving a Kyocera laser, with a couple of Macs talking to it.
>>> 
>>> The Add Printer dialog on the Macs works fine: always sees the CUPS printer within seconds - tried removing and re-adding, and there is no real delay in seeing “printer at pi" as a Bonjour device.
>>> 
>>> When printing, however, both Macs regularly - but intermittently - show “printer is not connected” or “looking for printer” for arbitrarily long periods. They always print in the end. 
>>> 
>>> Sometimes a “pause. resume” on the Mac queue will fix it, sometimes not. A restart of CUPS on the Pi always seems to fix it.
>>> 
>>> This doesn’t seem to depend on recent print activity: sometimes multiple jobs are delivered immediately after the first, sometimes the first is delivered immediately and the second is delayed, sometimes the first is delayed, etc. I can see no pattern.
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>>> https://lists.cups.org/mailman/listinfo/cups
>> 
>> _________________________________________________________
>> Michael Sweet, Senior Printing System Engineer
>> 
>> 
>> 
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>> ------------------------------
>> 
>> End of cups Digest, Vol 58, Issue 21
>> ************************************
> 
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_________________________________________________________
Michael Sweet, Senior Printing System Engineer