Another Modbus error: "Illegal data address"

Networking Solutions
1

Hooray!
Just resolved the “Illegal function“ modbus error with the release of RUTX_R_00.07.16.1, the router warned me of the new release RUTX_R_00.07.17 that I installed hoping it would solve some other issues.

Guess what? There is a new modbus error that popped up out of the blue: “Illegal data address“.

Is there any chance that Teltonika stops messing up the firmware without doing proper non regression testing?

I am now going to downgrade again to 16.1 to have at least a half working environment
Please provide solution asap.

2

Hello,

We apologize for any inconvenience this issue may have caused.

Please be informed that the 7.17 firmware version was removed due to an issue with the Failover functionality.
Version 7.17.1 will be available soon. Once it is released, kindly update your device and let me know if the issue persists.

We sincerely appreciate your understanding.

Best regards,

3

Hello,
the issue I found was regarding Modbus not Failover.
Is the oncoming version going to fix the Modbus error too?

Regards

4

Hello @pacman,

Apologies for the delay.

Could you please confirm whether the Modbus issue still persists on firmware version 7.17.4?

Best regards,

5

Hi Marija,
I am still running the 7.17.1 and I am not eager to install the 7.17.4 since the router is telling me that the last not stable available is the 7.17.3.
Another reason is also because I am tired of having the service disrupted because the new releases introduce new bugs.
Which are the changes into the 7.17.4 that prompted you to asking me? Is there any that should enhance the Modbus server and features?

Looking forward to hearing from you
Best regards

Roberto

6

Hello,

Rutx50 fw 07.17.4

rut956 fw 07.17.2

on Modbus Tester by PowerHud - “Illegal data address“.

7

Hello @pacman @Kris,

Apologies for any inconvenience this issue may have caused.

Could you kindly share the steps to reproduce this issue?

Best regards,

9

As notified by Kris another fw version and again a modbus error, exactly as I wrote in my last reply.
By now I will stick to the 07.17.1, no intention to have the service disrupted once again.

10

Hello,

First TCP Modbus client, I read data from one device (successful).

Second, I started Modbus server and add one source from client to address 1026 next change address to 2000, function 4, with remote access and without.

Tried to read on Modbus Tester by PowerHud but still blinking : “Illegal data address“.

External IP internal IP, different function, no luck.

Then remove source, only empty server, this same situation.

Screenshot 2025-09-23 at 21-31-17 RUT956 - Teltonika Networks
Screenshot 2025-09-23 at 21-31-17 RUT956 - Teltonika Networks1605×573 16.5 KB

Screenshot 2025-09-23 at 21-31-38 RUT956 - Teltonika Networks
Screenshot 2025-09-23 at 21-31-38 RUT956 - Teltonika Networks1581×940 31 KB

edit: i have 1 client connected and Failed requests: 171

on this computer i read from couple devices without any problem

in my SCADA , I can’t connect to Teltonika also

11

Hello,

on RUTX_R_00.07.18 firmware no change,

another Modbus tool : connected,

try to read : filed to execute Read: Error code: 2

12

Hello,

To investigate the issue further, we will need some sensitive information from your devices, such as the troubleshoot file.
I have sent a form to the email address you used to register on the community forum. Once the form is filled out, I will contact you privately.

For ticket references, please use the following IDs:

Thank you.

Best regards,

13

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15

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