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ago by
Hi there,

we have connected a RS232 serial device to a RUT955 device and we mannaged to commnicate with it without any problem using a third party SIM card with VPN and private fixed IP.

Now we want to connect to it using the Open VPN solution provided with the RMS and although we can connect with devices connected to ethernet easily using the videotutorial (thanks for that), we don´t know how to connect to the serial device.

Normally we use the port forwarding, (external 6785 to 50000, which happens to be the RS232), but in this case we don´t know how to configure it in the VPN configuration window inside RMS.

So, is there an easy way to do it?

Thanks for your help

Have a great day
ago by


Thank you for your query. Could you please clarify as to how your devices are configured and how exactly you're trying to reach your RS232 device? If I understand correctly, your RUT955 has its RS232 configuration enabled, it's working in server mode, serial type is "Over IP" and the router is listening for any request on port 50000 to forward to the RS232 device, correct? 

If this is, more or less, the correct configuration, then I'm assuming you want to reach the RS232 device from outside of RUT955 LAN via the RMS VPN? Just to be completely clear, I'd like to know if your topology would look something like this:

Any PC>Site 1 (any Teltonika router)>VPN RMS hub>Site 2 (RUT955 on port 50000)>RS232 device

Best regards,


2 Answers

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ago by

Thank you for the follow-up question. In your case it is possible to accomplish this but you will have to do some additional configuration on the RUT955 side. First, make sure you have your router R1 from site 1 and router R2 from site 2 connected to the RMS VPN hub. Additionally, I recommend configuring static IP leases in VPN hub for these devices. 

To make it work, first login into R1 router, navigate to Network>Firewall>General Settingsedit the RMS zone and in the inter-zone forwarding make sure to include "lan" zone in the "Allow forward from source zones" (or whichever zone the PC1 device belongs to). 

Then, login to R2 router, go to Network>Firewall>Port forwards and create new rule. Make sure to select the correct source zone by selecting the RMS zone. Then, simply proceed to configure a regular port forward rule by putting in the external port <any port> and pointing the forward to the router itself, port 50000. Once you save and apply the rule, you should be able to reach your RS232 device at site 2 from your PC1 which is at site 1.

Note: You don't have to enable any additional routing nor do you have to enable/disable any LAN/WAN forwarding in the VPN hub configuration. As long as the two routers can reach (ping) each other from R1 RMS IP to R2 RMS IP, this configuration will work. The only reason I'm recommending to add a static IP lease in RMS hub is to make sure PC1 can always reach RS232 via the same IP and port.

Let me know if you encounter any issues with this configuration.

Best regards,


Best answer
ago by
It worked straight away

Thanks a lot!
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ago by
Hello Tomas, thank you for your commebnt

the setup is as follows:

site 1 (PC with the necessary specific software+OPenVPN) > VPN RMS hub > Site 2 (RUT 955 on port 50000 and RS232 device.

The RS232 configuration is enabled and configured as you said and we can connect normally when we do it through an open public IP.

Now, we are trying to make use of the RMS-VPN but we don´t know how to configure the routing or which IP to call. I was calling the router internal IP with the idea that the port forwarding would do the job, but for the moment I couldn´t make it happen.