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Hi, we have several gateways TRB145 and TRB245 (fw 07.02.7 and earlier). If DNS settings are not set, data transfer via RS485 (TCP over IP) occurs with a timeout of about 5 seconds. But ping and trace requests are fine (50ms), as well as working with the web interface. With the DNS settings set (network with a DNS server), data transfer via RS485 is fine (without timeouts). Can you fix RS485 transfer without DNS settings on those gateways

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Could you please provide more details to better understand your issue? What is your network topology?

What DNS settings do you mean?

Does your provider not issue DNS servers or do you delete them manually?

How do you measure the difference?

Could you provide your testing set up, some screenshots?

Best regards,
From the gateway side, the operator issues a gray ip ( by setting a specific apn. The provider's network is connected to the enterprise network through an optical media converter (, and then through routers and switches ( to computers and servers. The provider issues DNS servers, but they do not include the topology of the enterprise (hidden behind NAT). The routes are spelled out correctly, which is confirmed by tracing from the enterprise network to the gateway and vice versa. Also pass ping requests in both directions.

By DNS settings, I mean the DNS settings in the mobile interface settings, as well as the "DNS forwardings" setting.

We measure the difference by sending a request to a device connected to the rs485 interface of the gateway and receiving a response from it from a computer in the enterprise network. The difference between request and response is about 5 seconds on a network without DNS (ping 50ms).

Could you try updating one of your TRB devices to the latest 7.03.4 firmware version with Keep settings option disabled, reconfigure your device and see if the issue is still present.

If it is, I would need you to attach a troubleshoot file to your question. Please, replicate the issue, then access router's WebUI, go to System -> Administration -> Troubleshoot section and download troubleshoot file from there. The logs in the file might provide more insight into the issue.

Best regards,