RUT956 Serial over IP (SSL/Client) fails to reconnect sessions after server restart

Networking Solutions Issue
1

I have alrady reached out to first line support, here is a more detailed description of the problem.
I have also found two forum topics that seem very similar to my issue: 16499 and 5245.

Description: I am using the RUT956 to connect to a selfhosted GO server via Serial over IP (TCP Client + SSL).

The connection works perfectly on a fresh start of the router. However, if the remote server (Docker container) restarts, the connection drops and the router fails to auto-reconnect, even though the “Reconnect Interval” is configured to 300 seconds. The router remains in a disconnected state indefinitely and does not try to reconnect at all.

Traffic: The connected GO server sends data to the client every second.

Symptoms:

  1. Server side restarts (TCP connection broken).

  2. Router eventually detects the drop via Keep Alive probes (WebUI shows Connected servers: 0/1). And “UP” for the serial over ip config.

  3. The Failure: The router stays disconnected indefinitely. It does not trigger the Reconnect Interval logic.

  4. The Workaround (Proof of Bug): If I simply toggle off click “Save & Apply” then toggle on and click “Save & Apply” in the Serial Configuration (without changing any settings), the router connects immediately. This should prove the network, IP, and Certificates are valid. Furthermore, a simple power cut of the router also triggers a reconnect.

Configuration:

  • Mode: Client

  • Protocol: TCP

  • TLS/SSL: Enabled (Certificate based)

  • Inactivity Timeout: 300 (we waited for 10 minutes and nothing happened)

  • Keep Alive: ON or OFF (did not make a difference for us)

    • Time: 30

    • Interval: 15

    • Probes: 3

Steps to Reproduce:

  1. Establish a Serial over IP (SSL with client SSL certifiactes) connection to a remote server.

  2. Start transmitting data from the server to the client.

  3. Restart the remote server application to force a socket break. (docker restart [container])

  4. Wait for the Keep Alive settings to detect the drop.

  5. Observe that the router marks the server as disconnected (0/1) but never attempts to reconnect automatically.

  6. Click “Save & Apply” → Observe immediate successful reconnection. (Or disconnect router from power and reconnect → immediate successful reconnection after reboot)

3

Hello,

For troubleshooting purposes, we will require more sensitive information from your end, such as the troubleshoot file, which may contain passwords, public IP addresses, serial numbers, and such. To avoid leaking this information, we have sent you a form to fill out, which you will receive in your e-mail inbox that you have registered your account with in the forums. In the Ticket ID field of the form, please enter the ID of this thread, which is 18147.

Please let me know once you filled out the form.

Thank you,
V.

4

Hello Vilius,

I have just filled out the form but there was no field to upload the troubleshooting file?

Best,
Max

5

Greetings,

I hope this message finds you well,

I can confirm that we received the form and I have provided with further instructions via Email.

Best regards,
V.

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