Setting up OpenVPN server on a RUT9xx

Hi all,

Second post here.

I’m trying to set up an OpenVPN server on a RUT956, version RUT9M_R_00.07.04.3

My goal is to have the router acting as a server and have Windows/iOS/Android/MAC connected as client to this server.

To simplify the configuration, I’m trying to use this option:

I thus used this, located here system/admin/certificates/generation

I managed to start the server side with basic configuration.
Furthermore, I managed to create the ovpn config file for the client, using the “simple” certificates / keys created on the server.

But I get this error :
2024-01-30 11:00:38 Certificate does not have key usage extension
2024-01-30 11:00:38 OpenSSL: error:0A000086:SSL routines::certificate verify failed:
2024-01-30 11:00:38 TLS_ERROR: BIO read tls_read_plaintext error
2024-01-30 11:00:38 TLS Error: TLS object → incoming plaintext read error
2024-01-30 11:00:38 TLS Error: TLS handshake failed

From my research, this seems to be related to the latest version of OpenVPN having tighter security.
I tried to find a solution, but after many hours of trying, I’m stuck.

I looked at many topics like those, but they do not apply exactly at what I’m trying to accomplish

I reached the vendor, but to resolve an issue, I need to pay $200 !
From what I read, if you did not buy directly from Teltonika, you cannot get support ?

For now, I will be using the old PPTP, but it’s unsecure and not supported on latest Android.

Any pointers/help will be appreciated.
Is there a how-to article for my use case? I did not find any.

FYI, I was using an ASUS router where OpenVPN is super easy to enable, and the router provides the client file and it works. I switch to Teltonika, to try a more robust router, but unsure if I will keep this route!


Considering your specific situation, I recommend using the Static Key method instead of generating TLS certificates. This approach would be sufficient for your needs in terms of security and scalability, especially since you only have two devices and don’t intend to connect a large number of devices. With this method, only one key needs to be generated between the VPN nodes.


You can find official instructions on how to generate static keys on the OpenVPN website: Static Key Mini Howto.

Best regards,


Ok, this does not meet my requirements.

  1. I need an OpenVPN server (the router) that will accept many clients from different sources (Android, MAC, iOS, Windows)
  2. I don’t need a point to point VPN between 2 routers.
  3. The link state “Limited scalability – one client, one server”
  • I need many client to one server.

I did a setup like this inside a few minutes with an off the shelf ASUS router, why is this not possible?


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