RUT241 port forwarding stops working after router reboot until RPi script is restarted

[lokeshCx]

I’m using a Teltonika RUT241 (LAN IP: 192.168.1.2) running as an OpenVPN client.
My setup:

• Raspberry Pi (LAN IP: 192.168.1.10) connected to RUT241

• Port forwarding rule on the RUT241 from 192.168.1.10:14551 to a remote VPN client, and the reverse direction as well.

The issue:
My Raspberry Pi boots faster than the router, my code starts sending UDP data through the router before it’s fully up. Once the RUT241 comes online, the port forwarding still doesn’t work — even though my script thinks everything is fine and keeps sending data.
It only starts working if I restart my script on the RPi after the router is online.

I initially thought it was an issue with my script, but I tested with a very simple UDP send/receive script and saw the same behaviour.

Also, if the RUT241 is restarted while the connection is active, I see the same problem — port forwarding doesn’t work again until I restart the script on the RPi.

What I tried:

• Delaying my RPi script startup to give the router more time to boot (this works, but feels like a workaround)

• Testing with a simple UDP send/receive script (same result)

Question:
Is there something in RUT241’s port forwarding or OpenVPN handling that causes this?

[Matas]

Hello,

In short, yes - the behavior is expected from how RUT241’s firewall + OpenVPN bring-up sequence works. Packets sent before the tunnel is ready are discarded, and UDP sessions aren’t automatically retried. Perhaps an addition to the script could be to poll the router or VPN endpoint before sending UDP requests, ensuring the tunnel is confirmed to be up and running.

Regards,
M.