OpenVPN Server - packet HMAC authentication failed

[GIAmbH]

Hi everyone,

we’re using a Teltonika RUTX50 as our router and have set up an OpenVPN server. The goal is to connect to it using a Windows OpenVPN client.

The client reports that the connection is successfully established, but we cannot reach any devices on the remote network.

Looking into the router logs, we repeatedly see the following error:

Authenticate/Decrypt packet error: packet HMAC authentication failed

However, in the OpenVPN configuration on the RUTX50, HMAC authentication is explicitly set to “none”.

We’ve double-checked the config and tried different settings, but the issue persists.

Has anyone experienced this before or knows what could be causing it? Any help would be greatly appreciated!

Thanks in advance,
Jan

[anon46660955]

Good afternoon,

In the first instance, if I can clarify what firmware you are using with the device? Please upgrade it to the newest.

Due to your description, I don’t see issues with the config yet, however I would like you to start from a clean config. Avoid reusing old certificates or settings.

Force auth none on both client and server.

I would also like to confirm if the router firewall allows traffic from the VPN to LAN?

Any Windows firewall or antivirus isn’t blocking the new VPN subnet?

Please also manually check configuration files on both server and client to ensure they match on both ends.

Regards,

Arturas