Question

All,

I connect remotely towards a device behind the RUT240 on TCP port 8096, but it terminate the connection. When I do is locally it doesn't happen. At my end nothing has been changed while at the remote end (the RUT240) IP address has been changed this to sending the TCP traffic to a specific LAN IP and port.

What can I do if it is the RUT240 which terminate the connection of the device itself?

In the wireshark, It looks like that the device is send a RST (reset flag).

Who can help me?

Thanks in advance

Answer 1

Hello,

I have a few questions since it’s not really clear what are the circumstances of your setup.

Do you have a public IP address?

Does your RUT240 have a dynamic IP, if yes, you would need to set up DDNS on your router, since it’s public IP is changing.

Do you have a static lease set for your LAN device, so that is has the same IP address all the time?

Do you have port forward set up in the routers firewall? If not, then try to set up a rule in WebUI -> Network -> Firewall -> Port forwards, then in the opened window:

• Enter the any name;
• For External port enter 8096;
• For internal IP address select your device‘s IP address;
• For internal port enter 8096;
• Click the ADD button;
• When a window opens, just clock SAVE & APPLY at the bottom to save the configuration;

Try to see if this resolved your issue.

If the issue persist, could you send us the troubleshoot file? The files attached are only seen for Teltonika Networks engineers. You can download the file from WebUI System -> Administration -> Troubleshoot and then download the troubleshoot file.

Also, could you provide the network topology of your solution with IP addresses, subnet masks and ports.

Regards,

Paulius

Comments

Hi Paulius,

I do have DDNS as my IP address change once every 24 hours or after a reboot.

I do have other port forwarded towards another device and that works fine, only the device with IP address 192.168.3.65 disconnects while if my laptop is on that network it doesn't.

I use the IP address 192.168.3.0/24, Use DHCP with static MAC addresses so, each device gets its configured. The working device uses ports 8094, 8095 and 8097 (RS485 to Ethernet ) the box which disconnect uses internal port 60001 and external 8096.

Will upload the troubleshoot file.

Rut240 troub;eshoot file

---

There could be an issue, that your device has no default gateway set up, that would explain why it works on the LAN network, but since the device has not default gateway set up, it does not know, how to sent the packet back out to the internet.

If the gateway is indeed set up and the problem persists, could try to disable the redirect rules on the firewall and just leave the port forward rule active and try to see if that solves the issue. For testing purposes, you could also remove the source IP address.

---

pcap file from local-end to remote end (local to RUT240)The device with IP .65 has a default gateway with DHCP.

I removed the redirect rules (Firewall => Traffic Rules), I also created a Port Forwarding for port 502 and redirect that to .65 without any source IP.

I can say, the source IP is always the same as I do have at home a static IP and want to restrict that a connection is only possible from my Home IP.

I also disabled the rule on 'Port forwards' and enabled the traffic rule and tried again. After I had doe that the error was changed to:

"No connection could be made because the target machine actively refused it x.x.x.x:8096"

When the Port Forwards was on, the box accept it but send a reset but this might also be done by the RUT240.