(See the README.md file in the upper level 'examples' directory for more information about examples.)
This example connects to the broker test.mosquitto.org using ssl transport with client certificate and as a demonstration subscribes/unsubscribes and send a message on certain topic.
It uses ESP-MQTT library which implements mqtt client to connect to mqtt broker.
## How to use example
### Hardware Required
This example can be executed on any ESP32 board, the only required interface is WiFi and connection to internet.
* Configure Wi-Fi or Ethernet under "Example Connection Configuration" menu. See "Establishing Wi-Fi or Ethernet Connection" section in [examples/protocols/README.md](../../README.md) for more details.
* When using Make build system, set `Default serial port` under `Serial flasher config`.
Generate a client key and a CSR. When you are generating the CSR, do not use the default values. At a minimum, the CSR must include the Country, Organisation and Common Name fields.
```
openssl genrsa -out client.key
openssl req -out client.csr -key client.key -new
```
Paste the generated CSR in the [Mosquitto test certificate signer](https://test.mosquitto.org/ssl/index.php), click Submit and copy the downloaded `client.crt` in the `main` directory.
Please note, that the supplied files `client.crt` and `client.key` in the `main` directory are only placeholders for your client certificate and key (i.e. the example "as is" would compile but would not connect to the broker)
### Build and Flash
Build the project and flash it to the board, then run monitor tool to view serial output:
```
make -j4 flash monitor
```
(To exit the serial monitor, type ``Ctrl-]``.)
See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
## Example Output
```
I (3714) event: sta ip: 192.168.0.139, mask: 255.255.255.0, gw: 192.168.0.2
I (3714) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE
