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Re: [mosquitto-dev] mosquitto.conf - subscribed topics using MQTT protocol 5

Hi Roger,

Many thanks for providing the video to use as a reference. By setting the value of persistence to 'true' at the broker configuration, the subscribed topics are retained.
Here are few questions w.r.t the configuration and behaviour:
- W.r.t mosquitto.conf available the default protocols are only set to 3 & 3.1.1. In the shared m.conf, the configuration of the protocol is not available. Is this ok? Shouldn't the protocol be explicitly set to support 3.1.1 & 5?

- Use of persistence on broker and clean start/clean session - I use paho_mqtt_c client to communicate with mosquitto. If 'persistence = true' in m.conf, is the value set from the client ignored? I observe that when 'persistence' is set to true, setting clean start = true/false doesn't change the behaviour. The subscribers are always stored. Is this expected?

On 21/04/21 1:52 am, Roger Light wrote:
Hi Bindu,

I've tested out this scenario and as far as I can tell it works as expected.

I've recorded a short asciicast of me doing that test so you can try
to investigate where the difference is:

If what you are doing is different, could you please describe what
exactly is different?



On Tue, 20 Apr 2021 at 17:38, Bindu Rao <bindu@xxxxxxxxxxxxx> wrote:

I am using mosquitto broker with paho_mqtt client. I notice a problem in
the following scenario:
- MQTT Protocol set to 5
- Clean start = false and session expiry interval set to 30 secs

I configure the client for publication and subscription on a topic.
Terminate and restart mosquitto.

Expected behaviour:
- Should be able to receive messages on a subscribed topics after
Actual behaviour:
- Session not remembered, hence need to be resubscribed even when clean
the start is set to false by the client.
I am using mosquitto - 2.0.10. The behaviour is perfectly ok when used
with protocol 3.1.1.
What configuration variables should be set in mosquitto.conf to get this
working? Could you please provide inputs?
Please note, that this works fine when I use other mqtt brokers.

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