MBedTLS W5500 TLS MQTT | WIZnet Makers

gabrielsaavedra995 · 2024-10-17T23:38:39+09:00

Hello everyone. I have been having issues connecting to an MQTT broker with the "Serverless" service from EMQX. I am using an STM32F411 and a W5500. I am establishing a secure TLS connection using the MbedTLS library, and I am using the PahoMqtt-embedded-c library for the MQTT operations. I am able to connect successfully to a local Mosquitto server. Similarly, I can connect to an MQTT broker using the "Dedicated" service from EMQX. However, when using the "Serverless" service, I receive an error "255" when calling the MQTTConnect function. I am mainly following these examples: https://github.com/eziya/STM32F4_HAL_ETH_MQTT_CLIENT_MBEDTLS/tree/master https://github.com/bangbh81/WIZnet-SSL-Example/tree/master https://github.com/WIZnet-ioLibrary/W5x00-TLS/tree/master Lastly, it's important to mention that I am not using a DNS service. I am using the IP address of my MQTT broker, obtained by passing the URL through Google’s DNS service (8.8.8.8). I noticed that all "serverless" brokers from EMQX share the same address. It seems related to SNI. From my research, I found the function mbedtls_ssl_set_hostname(). I am using it as follows: ret = mbedtls_ssl_set_hostname(tlsContext->ssl, "t0cabb21.ala.us-east-1.emqxsl.com"); However, the connection still fails, returning the same error 255. I would appreciate any advice on how to configure a connection to a broker that requires SNI, or any suggestions on what might be going wrong.

Log in to WIZnet Makers

Share projects and connect with makers.

Joined before the site update? first.

New to WIZnet Makers?

Sign up for WIZnet Makers

Already have an account?

Reset your password

Enter your email address. If it belongs to an account, we'll send a link to set a new password. Members who joined before the site update use this to set their password.

Know your password?

Need an account?