Successfully Configuring MQTT Over WebSockets With Azure IoT Hub

General
1

Hello everyone,

I wanted to share my recent success in configuring MQTT over WebSockets with Azure IoT Hub using the nRF Connect SDK. This journey was a bit challenging, but I managed to get everything working smoothly.

Problem Overview
I was trying to connect a device running the nRF7002DK to Azure IoT Hub using MQTT over WebSockets. The initial setup worked when using standard MQTT ports, but due to network restrictions, I needed to switch to WebSockets. This led to several issues, including connection timeouts and SSL handshake failures.

Key Challenges

  1. SSL Handshake Issues: The device was unable to establish a secure connection using WebSockets, resulting in SSL handshake errors.
  2. Certificate Verification: There were challenges with certificate verification, which caused the connection to fail.
  3. Timeouts: The connection would often time out after a short period, especially during prolonged use.

Solution
After extensive research and debugging, here’s what worked for me:

  1. Enabling Renegotiation:

    • I had to enable SSL renegotiation in the mbedtls configuration. This allowed the connection to remain active and secure over extended periods.

  2. Increasing Buffer Sizes:

    • I adjusted the buffer sizes in the network stack to handle the larger payloads typical with WebSockets. This prevented data overflow and ensured smooth communication.

  3. Custom TLS Configuration:

    • I modified the TLS configuration to explicitly support WebSockets. This involved setting the appropriate transport layer options and ensuring the correct cipher suites were enabled.

  4. Updating Certificates:

    • I updated the device certificates to ensure compatibility with Azure IoT Hub. This involved generating new certificates and ensuring they were correctly provisioned on the device.

Final Steps
After implementing these changes, I tested the connection extensively. The device now successfully connects to Azure IoT Hub over WebSockets, sends telemetry data, and receives cloud-to-device messages without issues.

Conclusion
Configuring MQTT over WebSockets can be tricky, especially with SSL and certificate management. However, with the right adjustments and thorough testing, it’s definitely achievable. I’m happy to share more details or help others who might be facing similar challenges!

Best regards,
[Your Name]