- MQTT Broker:
- MQTT broker address for clients: an IP address or a hostname used by the clients to communicate with the broker.
- MQTT broker internal address for backend: an IP address or a hostname used by the backend to communicate with the broker.
- MQTT broker port: a port number between 1025 and 65535, standard port is 1883.
- MQTT broker port for TLS: a port number between 1025 and 65535, standard port is 8883.
- Use TLS for clients: enables TLS communication between broker and clients.
- Use TLS for backend: enables TLS communication between broker and backend.
- CA certificate: is the certificate of an authority to verify the MQTT server.
- Cipher suite is used to limit the ciphers used with TLS.
- Client certificate server (Broker MQTT with TLS Enabled)
- Use client certificate: enables use of the client’s certificate.
- SSL certificate server for MQTT clients: url to the certificate server for MQTT clients.
- Firebase Cloud Messaging
- Enable this feature to use FCM, for devices with Android 8 or later.
- API Token: the server key, you can find it in your Firebase project settings > Cloud Messaging
After sending the certification request, the CA will very likely send back several files. One is the certificate, signed by the CA, and the others are intermediate certificates.
In Mosquitto the certificate must be the concatenation of the certificate delivered + the intermediate certificates.
The operating system must contain more certificates to establish a trust chain to the root certificate.
The MQTT protocol and FCM can be enabled at the same time, to use FCM be sure to read How to install the MDM Agent for Android 8 or later.