Openhab floods network with mdns

[Euphi (Ian Hubbertz)]

• Platform information:
  • Hardware: Opi5 Ultra
  • OS: dietPI
  • Java Runtime Environment: openjdk 17.0.15
  • openHAB version: 4.3.5
• Issue of the topic: openhab floods network with mdns queries

I setup a new SBC as homeserver. While everything was workinjg fine in the beginning, I noticed that suddenly network (wifi) became unreliable and that openhab used too much CPU (around 150% minimum).

Stopping openhab makes network reliable again.

I then used tcpdump to look whats going on in the network and saw that when openhab runs there is a flood of mDNS messages:

Short example (note the timestamps that this is a window of 17ms only):

11:55:15.000646 IP 192.168.0.242.mdns > mdns.mcast.net.mdns: 0 AAAA (QM)? C049EF8DABD0.local. (36)
11:55:15.001010 IP6 fe80::820c:f9ff:fec8:c271.mdns > ff02::fb.mdns: 0 AAAA (QM)? C049EF8DABD0.local. (36)
11:55:15.001580 IP 192.168.0.242.mdns > mdns.mcast.net.mdns: 0 AAAA (QM)? C049EF8DABD0.local. (36)
11:55:15.001736 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.002694 IP6 fe80::820c:f9ff:fec8:c271.mdns > ff02::fb.mdns: 0 AAAA (QM)? C049EF8DABD0.local. (36)
11:55:15.002712 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.003000 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.003159 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.003359 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.003575 IP 192.168.0.242.mdns > mdns.mcast.net.mdns: 0 AAAA (QM)? C049EF8DABD0.local. (36)
11:55:15.003745 IP6 fe80::820c:f9ff:fec8:c271.mdns > ff02::fb.mdns: 0 AAAA (QM)? C049EF8DABD0.local. (36)
11:55:15.003955 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.004609 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.004810 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.004960 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.006200 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.006216 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.006255 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.006290 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.007396 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.007443 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.008553 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.009328 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.009381 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.009431 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.009775 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.010674 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.010994 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.011104 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.011202 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.011352 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.011982 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.012142 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.014385 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.014552 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.015657 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.015809 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.015879 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.016042 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.016195 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.016360 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.016416 IP 192.168.0.242.mdns > mdns.mcast.net.mdns: 0 AAAA (QM)? C049EF8DABD0.local. (36)
11:55:15.016525 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.016608 IP6 fe80::820c:f9ff:fec8:c271.mdns > ff02::fb.mdns: 0 AAAA (QM)? C049EF8DABD0.local. (36)
11:55:15.016690 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d:0:7887:a8ff:fe02:feb8 (86)
11:55:15.016767 IP 192.168.0.242.mdns > mdns.mcast.net.mdns: 0 AAAA (QM)? C049EF8DABD0.local. (36)
11:55:15.016933 IP6 fe80::820c:f9ff:fec8:c271.mdns > ff02::fb.mdns: 0 AAAA (QM)? C049EF8DABD0.local. (36)
11:55:15.017067 IP 192.168.0.242.mdns > mdns.mcast.net.mdns: 0 AAAA (QM)? C049EF8DABD0.local. (36)
11:55:15.017082 IP6 fe80::7887:a8ff:fe02:feb8.mdns > ff02::fb.mdns: 0*- [0q] 1/0/0 (Cache flush) AAAA fd7a:d212:312d::ffe5 (55)
11:55:15.017201 IP6 fe80::820c:f9ff:fec8:c271.mdns > ff02::fb.mdns: 0 AAAA (QM)? C049EF8DABD0.local. (36)

Before this happened I installed the Matter addon and tried to add a Tasmota device with Matter turned on. (which failed, so I deactivated the matter addon and removed it - which was NOT successfull immediately. After reboot, it was still there and then I was able to remove it).

I have no idea what this C049EF8DABD0.local device is - however, openhab queries it immediately and nonstop after restart or reboot.

As a quick fix, I stopped two of the bundles related to mDNS:

openhab> bundle:list | grep -i mdns
 58 │ Active   │  80 │ 3.5.12                │ JmDNS
172 │ Waiting  │  80 │ 4.3.5                 │ openHAB Core :: Bundles :: Configuration mDNS Discovery
187 │ Resolved │  80 │ 4.3.5                 │ openHAB Core :: Bundles :: REST mDNS Announcer
194 │ Resolved │  80 │ 4.3.5                 │ openHAB Core :: Bundles :: mDNS Service
258 │ Waiting  │  80 │ 4.3.5                 │ openHAB Core :: Bundles :: Configuration USB-Serial Discovery using ser2net mDNS scanning
265 │ Waiting  │  80 │ 4.3.5                 │ openHAB Core :: Bundles :: mDNS Suggested Add-on Finder

How can I come to a clean solution (= all bundles are active and openhab no longer floods my network)?

[Euphi (Ian Hubbertz)]

Openhab floods network with mdns

[mvbergen]

Looks a lot like the issue I had:

Multicast issues leading to severe network and server degradation

Platform information: Hardware: armv7l, x86_64 OS: debian, armbian, raspberryos Java Runtime Environment: zulu17.46+19, openjdk 17.0.9 openHAB version: 4.1.1 Issue of the topic: Multicast advertisement of openHAB instance leads to avahi errors flooding the logs (/var/log/syslog) with avahi_normalize_name() failed messages. I started to investigate this issue when I noticed serious network performance degradation (made worse by running multiple openHAB servers on my network) and even non…

I still have no idea what was causing this but turning off mdns (as per linked post) for openHAB made the problem disappear.

Particulars of my setup that may provide clues to other with similar problems:

• Multiple openHAB instances on the network with items connected with the Remote openHAB binding.
• Router / firewall OPNsense
• Omada controlled network

Perhaps others with this issue have some similarities with the above.

[lsiepel (Leo)]

Same issue. Reported here

openHAB taking up all cpu cycles

Two days ago i noticed openHAB was no longer responsive. It looked like some resource issue as the whole system was slow. After some updates and reboots it improved. Still see mayor issues with performance. I noticed both java and node (for zwavejs-ui) are taking up many resources. uptime shows a load of: 4,79, 4,95, 5,00 So i looked into openHAB threads and got this: [image] I fiddled with uninstalling bindings and was unable to determine the culprit. Any advice on how to determine the iss…

I noticed my Ubiquiti dream machine was updated with some mDNS changes, when I disable mDNS on the UDM, openHAB no longer uses all cpu cycles.