OpenHab server throwing DNS error messages from unrelated Android tablet

[Joe Barneson]

I have an odd Java issue that just cropped up and I'm wondering if anyone else has ran into it. Below are the errors that are repeatedly spewed out in my console every 10 minutes. A quick google search found this bug report discussing UDP port scanning, but it's old (2011). I ensured I had the most updated version of Java installed.

In the errors below, the client being referenced is a Nexus 7 tablet running latest android. It does not currently have OpenHab installed on it -- I don't think it ever did. I have a lot of tablets and phones in my house (10+) and this is the only device referenced by OpenHab in this way... any help or pointers would be appreciated, although I'm probably going to enjoy some outside time and holiday fireworks later, so I may not be responsive today. 

08:06:02.617 ERROR j.j.i.DNSIncoming$MessageInputStream[:138] - bad domain name: possible circular name detected. Bad offset: 0xffffffff at 0x31

08:06:02.618 ERROR j.j.i.constants.DNSRecordType[:303] - Could not find record type for index: -1

08:06:02.619 ERROR javax.jmdns.impl.DNSIncoming[:286] - Could not find record type. domain: _googlecas?.

dns[query,192.168.1.176:5353, length=51, id=0x0, questions=1

questions:

        [Pointer@1834040 type: TYPE_PTR index 12, class: CLASS_IN index 1, name: _googlecast._tcp.local.]]

        question:      [Pointer@1834040 type: TYPE_PTR index 12, class: CLASS_IN index 1, name: _googlecast._tcp.local.]

   0: 0000000000010001 000000000b5f676f 6f676c6563617374 045f746370056c6f     ........ ....._go oglecast ._tcp.lo

  20: 63616c00000c0001 0b5f676f6f676c65 636173                                cal..... ._google cas

08:06:02.627 WARN  j.j.i.constants.DNSRecordClass[:129] - Could not find record class for index: -1

08:06:02.629 ERROR javax.jmdns.impl.DNSIncoming[:291] - Could not find record class. domain: _googlecas?. type: TYPE_IGNORE index 0

dns[query,192.168.1.176:5353, length=51, id=0x0, questions=1

questions:

        [Pointer@1834040 type: TYPE_PTR index 12, class: CLASS_IN index 1, name: _googlecast._tcp.local.]]

        question:      [Pointer@1834040 type: TYPE_PTR index 12, class: CLASS_IN index 1, name: _googlecast._tcp.local.]

   0: 0000000000010001 000000000b5f676f 6f676c6563617374 045f746370056c6f     ........ ....._go oglecast ._tcp.lo

  20: 63616c00000c0001 0b5f676f6f676c65 636173                                cal..... ._google cas

08:06:04.552 ERROR j.j.i.DNSIncoming$MessageInputStream[:149] - Extended label are not currently supported.

08:06:04.554 ERROR j.j.i.DNSIncoming$MessageInputStream[:149] - Extended label are not currently supported.

[Paul Hampson]

Total hunch/speculation - but maybe it has something to do with the openhab service discovery (cannot paste a link from my phone it seems).

The host name googlecast sounds like something is searching for a Chromecast device maybe? Do you have one? If not are you using an app that supports chromecasting? I guess the chrome cast uses some sort of service discovery like openhab has and it is upsetting the openhab library somehow.

Hope that helps.
Paul

[Kai Kreuzer]

The same was reported in the KNX user forum: http://knx-user-forum.de/openhab/36016-_googlecast-_tcp-local.html

It seems that the jmDNS library for the Bonjour support in openHAB has problems, if there is a Cromecast in the same network.
Feel free to enter an issue about that.

Regards,
Kai

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[Joe Barneson]

Yeh - I have two chromecasts.... interesting that it's just our one tablet that's causing that error by scanning. Our phones / tablets that we normally use to chromecast aren't searching apparently. 

Joe Barneson
Director of Product & Engineering

SOLOMO Technology
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[Christoph Wempe]

I already created an issue for this a few days ago.

https://github.com/openhab/openhab/issues/1203

I think it does no harm, but every error should be solved, eventually.

[Joe Barneson]

Thanks Christoph - agreed, it doesn't appear to be causing any problems... I'm in exploratory mode with new hardware though, so it's making diagnostics a bit harder. If I used log persistence, does anyone have a good streaming log application they use? 

(sorry, reposting removing my email signature)

[Joe Barneson]

Quick update - I found this was a specific app I had on a few of my androids throughout the house. The app is called Tinycam Pro. Starting up and killing that app on various clients spurred the log messages in OH. 

I'd love to give that developer some feedback, does anyone have constructive feedback I could post for him? He just recently added chromecast support, so I wonder if it was introduced then.

Last - any suggestions how I could suppress this packages errors in OH for the console? Now that I know the source, it's easy to turn off the app, but would be nice to have more granular control over the console and log outputs. Thanks

[Christoph Wempe]

It looks like you guys are on your way to solve this issue.

https://github.com/openhab/openhab/issues/1203

But is there a workaround to disable these messages in the log until this is solved in v1.6 or whatever?

[joe...@gmail.com]

I had the same problem using chromecast.

Worked around this by simply disabling the exceptions in the log (until it's fixed). Go to your configuration directory and add a couple of loggers in your logback.xml file.

ie.

        <logger name="javax.jmdns.impl.DNSIncoming" level="OFF" />

        <logger name="javax.jmdns.impl.constants.DNSRecordType" level="OFF" />

        <logger name="javax.jmdns.impl.constants.DNSRecordClass" level="OFF" />

Regards,

Joe

[Christoph Wempe]

Thanks

[Joe Barneson]

That's exactly what I was hoping to use. Thanks for pointing it out.

[a...@albriggs.com]

Great - the update to the latest apple TV is also causing this to happen - grey solution!