Android Question [Solved]Problem with MQTT broker in Android 9...

[rbghongade]

Dear friends,
My project involves an ESP8266 device connecting to a hotspot created by Android device. After connecting to the hotspot, the device connects to MQTT broker service running on the same Android device.
This is successful with Android 8 but when switched to a new phone with Android 9 , the ESP8266 connects to the hotspot but is unable to connect to MQTT broker.
Since all required permissions are in place, I am unable to figure out the reason.
Is there any special permission for the same in Android 9?
I tried the same connections with a router instead of Android hotspot (MQTT broker service still on Android) and it works as expected.
Kindly advise.

 

[Erel]

I tried the same connections with a router instead of Android hotspot (MQTT broker service still on Android) and it works as expected.

In that case the issue is not related to the broker or your app. It is a network issue.

Are you able to connect to B4A-Bridge when the PC is connected to the hotspot: https://www.b4x.com/android/forum/t...r-wifi-without-a-local-network.55037/#content ?

 

[rbghongade]

Not able to connect to B4A-bridge with hotspot with this new phone (Oneplus 6)
Old phone (MI 5 connects correctly).

It seems that the default ip for the phone is not 192.168.4.1 but is allotted new every time!
This creates a problem since mqtt broker address changes .

 

[Erel]

It seems that the default ip for the phone is not 192.168.4.1 but is allotted new every time!

I don't think that you can do anything about it.

You can use one of the ESP8266 boards to create a hotspot.

 

[rbghongade]

Can we get the DHCP server ip and use it as mqtt broker ip?

 

[Erel]

Start with testing it from the PC. I'm not sure whether the default gateway will help here.

Might be useful: https://www.b4x.com/android/forum/threads/mqtt-chat-with-auto-discovery.75713/

 

[rbghongade]

Solved the issue with obtaining gateway IP and using the same for mqtt_server. Thanks Erel.