How to send and receive messages with mosquitto_sub and mosquitto_pub to MyQttHub.com

[francis.brosnan]

1. Connecting with Mosquitto without using TLS

Follow next indications to connect with mosquitto_sub y mosquitto_pub to MyQttHub.com:

1. Create a couple of credentials if you do not have them (look at the following link: How to create and manage your MQTT devices with MyQttHub.com )

2. You must create two credentials: one for sending and another to receive messages. If you want to reuse same credentials look at: How to skip MQTT connection replace, reusing same credentials

3. Now, to connect (without using TLS), run the following command (replacing , y with your credentials):

   >> mosquitto_sub -h node02.myqtthub.com -i <client-id> -u <username-> -P '<password>' -t message/topic/to/subscribe -q 2

4. Previous command will subscribe and print all messages received on that topic. Now, in another terminal and without stopping previous command, send messages with the following:

   >> mosquitto_pub -h node02.myqtthub.com -i <client2-id> -u <username2> -P '<password2>' -t message/topic/to/subscribe -m "hello world"

If everything went ok, you will see messages sent printed at the terminal running mosquitto_sub.

2. Connecting with Mosquitto using TLS

Now, to connect to MyQttHub.com using TLS and mosquitto_sub and mosquitto_pub you will have to add “-p 8883 --capath /etc/ssl/certs” like this:

`>> mosquitto_sub -h node02.myqtthub.com -p 8883 --capath /etc/ssl/certs -i <client-id> -u <username-> -P '<password>' -t message/topic/to/subscribe -q 2`

These options are:

1. -p 8883 instruct mosquitto to connect to 8883 TLS port
2. --capath instruct mosquitto where to find public root certificates to complete client certificate trust chain.
3. These options (-p and --capath) must be configured on both commands (mosquitto_sub and mosquitto_pub).

[shahrasel]

hello,
I tried #3 to connect and run with the following code in terminal command:
“mosquitto_sub -h node02.myqtthub.com -i client1 -u shahrasel -P ‘my_pass’ -t message/topic/to/subscribe -q 2”
it’s showing me “Connection error: Connection Refused: broker unavailable.”
Could you kindly tell me what mistake did I make?

[francisco.lopez]

Hello,

See the following link for common errors with mosquitto_sub:

Common mosquitto_sub errors when connecting to your MQTT broker and how to fix them

Here is a list of known errors that you can get while connecting with mosquitto_sub. The following indications use -d (–debug) option to get more verbose output. Consider the following indications. Firewall in place. If you run mosquitto_sub with -d option (–debug) and get no single line of output like this: >> mosquitto_sub -d -h node02.myqtthub.com -i myHubxxxxIdMosq -u myHubxxxxIdMosqUsr -P xxxx -t message/topic/to/subscribe -q 2 (command issued, waiting and without showing no input) T…

It seems you are using wrong clientId, userName or passwords.

Best Regards,