# MQTT broker confusion in OH3 **URL:** \ **Category:** Migration\ **Tags:** mqtt, openhab3\ **Created:** [December 22, 2020, 11:30am UTC](https://community.openhab.org/t/mqtt-broker-confusion-in-oh3/110822 "2020-12-22T11:30:40Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![jwveldhuis](https://community.openhab.org/user_avatar/community.openhab.org/jwveldhuis/32/21522_2.png) [@jwveldhuis](https://community.openhab.org/u/jwveldhuis)\ **Post date:** [December 22, 2020, 11:30am UTC](https://community.openhab.org/t/mqtt-broker-confusion-in-oh3/110822/1 "2020-12-22T11:30:40Z")
I’m coming from OH2.5 where I used the 1.x MQTT binding with an external Mosquitto broker. After a lot of research I found that you need to create a bridge Broker and a Generic MQTT thing and then add channels for each topic. A bit complex to setup, but it works. Now somehow I also have a “ **MQTT system broker connection** ” at the Settings page. What does this MQTT system broker do, and do I need to configure it? It keeps complaining about the host/IP not being setup, but looks like I don’t need this? How can I can rid of this entry? `2020-12-22 12:04:14.458 [WARN] [.MqttBrokerConnectionServiceInstance] - MqttBroker connection configuration faulty: host : You need to provide a hostname/IP!` ![image](https://community-openhab-org.s3.dualstack.eu-central-1.amazonaws.com/original/3X/a/a/aafccc4cd7e7e736e22f730f038df170d5a8f1d3.png) ---
**Author:** ![rlkoshak](https://community.openhab.org/user_avatar/community.openhab.org/rlkoshak/32/75251_2.png) [@rlkoshak](https://community.openhab.org/u/rlkoshak)\ **Post date:** [December 22, 2020, 5:52pm UTC](https://community.openhab.org/t/mqtt-broker-confusion-in-oh3/110822/2 "2020-12-22T17:52:43Z")
> [@jwveldhuis](#): > > What does this MQTT system broker do, and do I need to configure it? I _think_ that’s a way to set up a “default” MQTT broker connection. You don’t need to do anything there if you create Broker Things. But I’m not really sure. I haven’t messed with it. Have you edited or even just clicked “save” from that menu? You do need the host/IP to have a valid MQTT connection to a broker. If you’ve clicked save, perhaps it generated an empty config and that’s what it is complaining about. You can see if you have a $OH\_USERDATA/config/org/openhab/mqtt.config file. If so try stopping OH and deleting it. ---
**Author:** ![Qwerty\_Zet](https://community.openhab.org/user_avatar/community.openhab.org/qwerty_zet/32/60411_2.png) [@Qwerty\_Zet](https://community.openhab.org/u/Qwerty_Zet)\ **Post date:** [December 22, 2020, 6:13pm UTC](https://community.openhab.org/t/mqtt-broker-confusion-in-oh3/110822/3 "2020-12-22T18:13:07Z")
See post nov 29. > [@openHAB 3.0 Milestone 2 discussion](https://community.openhab.org/t/openhab-3-0-milestone-2-discussion/107564/240): > > In OpenHab 3 settings do you see “MQTT Broker connection”? If so, click the link. The info on this page was blocking port 1883 so Mosquitto didn’t connect. I removed all the info on this page and saved the page. Restart Openhab and Mosquitto, as port 1883 was not blocked anymore, Mosquitto could connect. Perhaps a reboot is needed. Edit: after that, the error message in you log should be gone. Zet hem op 🙂 ---
**Author:** ![jwveldhuis](https://community.openhab.org/user_avatar/community.openhab.org/jwveldhuis/32/21522_2.png) [@jwveldhuis](https://community.openhab.org/u/jwveldhuis)\ **Post date:** [December 22, 2020, 7:48pm UTC](https://community.openhab.org/t/mqtt-broker-confusion-in-oh3/110822/4 "2020-12-22T19:48:08Z")
Thanks, it lead me to the solution. In my case it was the file `mqttbroker.config` in that `$OH_USERDATA/config/org/openhab/ ` dir (created over a year ago) that was causing the error to show. Deleted it and all is fine now. @Qwerty_Zet I tried your solution too, in my case it didn’t solve it. Toch bedankt! ---
**Author:** ![haybolat](https://community.openhab.org/letter_avatar_proxy/v4/letter/h/7993a0/32.png) [@haybolat](https://community.openhab.org/u/haybolat)\ **Post date:** [December 26, 2020, 5:33pm UTC](https://community.openhab.org/t/mqtt-broker-confusion-in-oh3/110822/5 "2020-12-26T17:33:42Z")
> [@jwveldhuis](#): > > hanks, it lead me to the solution. > In my case it was the file `mqttbroker.config` in that `$OH_USERDATA/config/org/openhab/ ` dir (created over a year ago) that was causing the error to show. Deleted it and all is fine now. > > @Qwerty_Zet I tried your solution too, in my case it didn’t solve it. Toch bedankt! Although I have just installed it, I did not have any settings. I did what you said above. not resolved. Why don’t the friends who write OH3 see these problems and offer suggestions for solutions? ![image](https://community-openhab-org.s3.dualstack.eu-central-1.amazonaws.com/original/3X/8/7/87ad944d048ecaf9033da2d346412d58618fab2e.png) ---
**Author:** ![jwveldhuis](https://community.openhab.org/user_avatar/community.openhab.org/jwveldhuis/32/21522_2.png) [@jwveldhuis](https://community.openhab.org/u/jwveldhuis)\ **Post date:** [December 27, 2020, 12:50pm UTC](https://community.openhab.org/t/mqtt-broker-confusion-in-oh3/110822/6 "2020-12-27T12:50:11Z")
My issue was an error in the log, not an empty settings page. Did you install the MQTT binding?