# After deploy flow containing mqtt node, new connection is created, old connection remains open
**URL:** https://discourse.nodered.org/t/after-deploy-flow-containing-mqtt-node-new-connection-is-created-old-connection-remains-open/61928
**Category:** General
**Tags:** mqtt
**Created:** [28 April 2022 15:03 UTC](https://discourse.nodered.org/t/after-deploy-flow-containing-mqtt-node-new-connection-is-created-old-connection-remains-open/61928 "2022-04-28T15:03:00Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@alexwala](https://discourse.nodered.org/u/alexwala)
#### Post date: [28 April 2022 15:03 UTC](https://discourse.nodered.org/t/after-deploy-flow-containing-mqtt-node-new-connection-is-created-old-connection-remains-open/61928/1 "2022-04-28T15:03:00Z")
Having a simple flow with a mqtt node (broker clientId set to autogenerated, port 8883).
After first deploy there is exactly one connection to the mqtt broker.
(sudo netstat -nputw | grep 8883)
With each subsequent deployment the number of connections increases, as always a new connection is created and the old one is not disconnected...
If using a fixed clientId the issue does not occur - the number of connections is always 1.
using node-red v2.2.2
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### Author:  [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)
#### Post date: [28 April 2022 15:07 UTC](https://discourse.nodered.org/t/after-deploy-flow-containing-mqtt-node-new-connection-is-created-old-connection-remains-open/61928/2 "2022-04-28T15:07:27Z")
What broker are you using and how have you configured the connection?
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### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [28 April 2022 15:09 UTC](https://discourse.nodered.org/t/after-deploy-flow-containing-mqtt-node-new-connection-is-created-old-connection-remains-open/61928/3 "2022-04-28T15:09:40Z")
I suspect it is the very same issue am working on right now.
Thanks for letting us know.
I'll keep you posted when a solution is found.
PS: In the mean time - use "Modified Nodes" method to minimise the impact (especially if you are NOT modifying an MQTT node) because "Full" causes all nodes (even ones you havent touched) to be re-created.
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### Author:  [@alexwala](https://discourse.nodered.org/u/alexwala)
#### Post date: [2 May 2022 06:34 UTC](https://discourse.nodered.org/t/after-deploy-flow-containing-mqtt-node-new-connection-is-created-old-connection-remains-open/61928/4 "2022-05-02T06:34:48Z")
tried with different broker's (hivemq, mosquitto)
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### Author:  [@alexwala](https://discourse.nodered.org/u/alexwala)
#### Post date: [2 May 2022 06:35 UTC](https://discourse.nodered.org/t/after-deploy-flow-containing-mqtt-node-new-connection-is-created-old-connection-remains-open/61928/5 "2022-05-02T06:35:29Z")
thanks for suggestion with 'Modified Nodes'.
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### Author:  [@greengolfer](https://discourse.nodered.org/u/greengolfer)
#### Post date: [2 May 2022 13:19 UTC](https://discourse.nodered.org/t/after-deploy-flow-containing-mqtt-node-new-connection-is-created-old-connection-remains-open/61928/6 "2022-05-02T13:19:32Z")
> [@alexwala](#):
>
> tried with different broker's (hivemq, mosquitto)
QOS value and retain will change the behaviour. Upon losing the connection with a client the broker will maintain the connection for a while so that the same client reconnects it will find the messages waiting for him.
When using the same client\_id you force reusing the same "queue" hence the same TCP connection on the broker.
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### Author:  [@Barbudor](https://discourse.nodered.org/u/Barbudor)
#### Post date: [3 May 2022 07:48 UTC](https://discourse.nodered.org/t/after-deploy-flow-containing-mqtt-node-new-connection-is-created-old-connection-remains-open/61928/7 "2022-05-03T07:48:11Z")
> [@greengolfer](#):
>
> QOS value and retain will change the behaviour.
I would say that "Clean session" is key
I'm using either one of those 2 combinations:
- empty (automatic) client\_id and "Clean session" checked : the broker clear the client context in case of disconnection
- fixed client\_id and "Clean session" unchecked : the broker keeps the client context in case of temporary disconnection. **If a new connection comes with the same client\_id, the older one is closed by the broker.**
I don't say that other combinations are useless, just that I have no use-case for them.
So from your description it looks like the combination of "automatic client\_id" and "Clean session unchecked" leaves MQTT connection in the background that are neither closed by Node-RED nor the broker.
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### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [2 July 2022 07:48 UTC](https://discourse.nodered.org/t/after-deploy-flow-containing-mqtt-node-new-connection-is-created-old-connection-remains-open/61928/8 "2022-07-02T07:48:24Z")
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