Establishing an SSL connection over GSM

Using Arduino Project Guidance
1

Hi everyone,

I am trying to make an IoT device where I'd like to send some sensor data over a cellular network. I would like to use a GSM module for this project. I have a server that will receive the data over MQTT. My main problem is that my server will only connect over SSL. I have a custom CA certificate generated by my server that I need to apply while establishing a connection to the server along with a userid and password. I have to have use this sever only and it will not work without this SSL certificate. However, I have no idea how I should approach this using GSM.

  1. Can you please suggest me which GSM module should I choose? As I was unable to figure out which one would support mqtt with SSL.

  2. Can you suggest me how should I code this? For example some relevant examples or libraries.

I am planning to use an arduino uno and a DHT11 sensor for this project.

I am right now using a nodemcu to send data over wifi. For reference, my present code is in the following post on one of my earlier topics.
Problem with CA certificate for SSL - #2 by techiiieee

Thanks for help

2

If I don't mess up....
GSM is the telephone network and it's not the same as Wifi & Co.
Does the distance allow use of Wifi directly and drop the GSM stuff?

3

SSL work over TCP/IP - so it neither knows nor cares what type of connection is beneath the TCP layer.

So your basic requirement is any module that supports TCP/IP.

No doubt, some modules will have SSL built in - it will be stated in the specifications.

4

Actually, I intend to use the device where wifi will not be available and maybe to monitor stuff that may move from one place to another.

Can you please suggest how can I do that? How can I add my own CA certificate? Can I implement that using a SIM800L? if yes, can you please suggest me any examples or any library?

Can you please provide any examples of such modules?

Thank you so much for your help

5

Have you looked?

6

Okey. It was a last guess.

7

So after a lot of research, I have ordered a module with a 4G Lte Gsm Modem (A7672S). I chose this because its specifications said that it supports SSL. Can anyone now help me with how I can program to send my sensor data to my MQTT server using SSL using my custom certificates?

Thanks

8

Hi! Did you find a working solution? I'm trying to connect to AWS IOT MQTT server, but with the GSM connection it fails to connect.
Thank you

9

what modem are you using ?
I recently used a Quectel EC21 to use MQTT over SSL
none trivial - multiple AT commands
you need to read the SSL/TLS sections of your modem manual to find the correct AT commands to use
Quectel usually give examples of use

10

Hi Horace, I'm using this device: T-SIM7080G-S3 ESP32-S3, which has a built in modem 7080.

With Mosquitto MQTT server on port 1883 it works fine, but when trying to connect to AWS IOT with 8883, I set up the certificates using AT commands, but something has to be wrong, as the connection cannot be established. (If using a WIFI connection and the AWS IOT client this certificates work well)

I have also tried to find a solution using ChatGPT and Bard, but they also fail...

The main problem is that I cannot find documentation on how to proceed.

11

I don't have a SIM7080 so difficult to give practical help

have you had a look thru the file downloads on SIM7080G web page

maybe worth changing the post title to mention SIM7080

12

Thank you, I'll have a look at this link!

13

I gave up, no success. I'll go on with MQTT without SSL. Thank you!

14

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.