Q: What keeps bonjour printers visible on the network?

That's the result of a malfunctioning Bluetooth device on the network, most likely either the printer itself or a third-party wireless router with incompatible settings or firmware. Restarting the router may help, temporarily. Otherwise, refer to the manufacturer for support.

Open airport utility via spotlight > open spotlight preferences , follow the screen shot settings .

I meant "Bonjour," not Bluetooth.

In theory what is supposed to happen is that your Mac sends out a Bonjour query asking for all Bonjour capable printers to advertise themselves and it then lists the results. You can do the equivalent in Terminal as follows.

dns-sd -B _printer._tcp .

You then have to press Control-C to stop the Mac listening for responses.

I would feel that this may be a combination of a bug in the Kyocera and possibly a bug on your Mac. There have been known problems in certain versions of Apple's operating system in the past although none like this in El Capitan 10.11.5 that I am aware of.

I would recommend speaking to your Kyocera supplier and asking if they can check and if possible upgrade the firmware of your Kyocera or if it is possible download and upgrading the firmware yourself. Some makes of printer also have the ability to turn off Bonjour completely. This would stop it obviously but would mean you would have to manually add the printer via its TCP/IP address.

We have a mixture of HP and Konica-Minolta printers and while firmware updates for most of the HPs can be done ourselves, the Konica-Minolta updates have to be done by our supplier/maintainer.

Some Bonjour device was advertising itself on the network as a Kyocera printer, or was inaccurately reflecting such an advertisement. I don't have any way of knowing what it was. If I understand your last comment, you seem to have solved the problem.

If you have a Mac connected to WiFi and Ethernet with both networks being bridged via a WiFi base-station then this might be a cause since the Mac would see the same printer on both networks and try renaming one instance and would likely get in a loop.

Similarly if the printer itself is connected via both Ethernet and WiFi the same might happen.

Yes the Bonjour name can be changed automatically by the device and will be if it is detecting something else already using the same name, hence my explanation of how having a device connected twice to the same network may be a cause. I suppose two Ethernet connections from a Mac to the same network would equally apply.

Also the command line tool I mentioned in my previous reply i.e. dns-sd can also be used to manually rename devices and even to register fake devices.

Apple's AirPort Extreme base-stations act as bonjour sleep proxy servers and will therefore keep advertising devices if they are asleep and unplugged devices may or may not get counted the same way. An Apple TV can also do this but if it detects and Apple AirPort Extreme it disables itself from doing this.

Again you can use dsn-sd to see if you have any Bonjour Sleep Proxy Servers on your network as follows, remember to do Control-C after a while.

dns-sd -B _sleep-proxy._udp local

Hello AndrazH,

At one point someone explained to the exactly what causes this. It is a network race condition between machines. It was particularly bad on certain older (but not too old) versions of OS X and iOS. There was a point quite recently where Apple tried a new version of Bonjour and caused this widespread issue. If you have a device (just one) on your network that is still using the old (but not too old) protocol, you will get this result. The solution is to update all devices to the most recent OS version, turn off all devices on the network, then turn them all back on.

AndrazH wrote:

 

Etresoft, do you know which versions of OSX/iOS are problematic and can cause this kind of behaviour?

Hello again AndrazH,

I can tell you when Apple fixed it. Apple removed the "discoveryd" process in 10.10.4 (http://www.macrumors.com/2015/06/30/apple-releases-os-x-10-10-4/) and iOS9 (https://9to5mac.com/2015/06/10/ios-9-os-x-10-11-discoveryd-mdnsresponder-network -bugs/). I assume it was introduced in 10.10 and sometime earlier in the iOS8 releases. All Apple code starts in iOS these days. Due to the nature of this bug, if you have any device on your network that has the problematic software, all devices may show problems. Then again, pretty much anything Apple does these days is horribly complicated. While we can definitively state that this is a Bonjour problem, it is really hard to say what the cause is. It could be the problematic "discoveryd" software on your network. It could be something else entirely.