we use a RUTX50 network router in a fire brigade vehicle and we would like connect a DJI RC Pro drone controller with the 2.4 GHz WLAN of the router. The WLAN connection is being successfully established and we get a valid IP configuration via DHCP, but we can´t access the Internet or devices on the local network. Other WLAN devices (iPads, Google Pixel 6) are working fine.
What we have already investigated:
RUTX50 and DJI Controller are running with the latest and greatest firmware version (RUTX_R_00.07.07.2_WEBUI.bin).
The same DJI Controller gets a connection on a different WLAN access point and network.
Static IP address configuration instead of DHCP.
5 GHz WLAN instead of 2.4 GHz.
TCP dump on RUTX50 on all interfaces does not capture any transmitted packages to or from the IP address of the DJI controller.
Does anyone have any idea what the root cause could be and how we can solve this problem?
So RUTX50 can connect to internet and the devices that are connected to RUTX50 can’t get internet connection, am I right? And what are you trying to achieve? Are you only trying to provide an internet access from the RUTX50?
RUTX50 and all the connected devices (LAN ports and WLAN) can connect to internet, except the DJI drone remote controller. This is the only device which can´t connect to internet and which can´t connect to other devices connected to the RUTX50.
So, RUTX50 can connect to the internet and LAN devices also can connect internet except DJI drone remote controller.
May you ping the DJI drone remote controller from the router?
Also, can you please check if the ARP requests that are sent to the drone remote controller failing? You can check it from the CLI of the device via tcpdump.
I had enabled TCP dump on all interfaces in the RUTX50 web UI and pinged the DJI controller (192.168.121.189) which failed.
In the dump I can see two gratuitous ARP packages from the DJI controller. The sender MAC address does match with the MAC address shown on the DJI controller UI.
Later in the trace I can see the ping requests from RUTX50 to 192.168.121.189. All are failing with “no respone found!”. See here:
It’s clear that ARP requests are sent from our router to the remote drone controller. And there is no response sent from the drone controller.
You may try adding permanent ARP entries manually and monitor all the pinging from Teltonika side.
I also deleted the screenshots that you’ve shared. As it contains some sensitive information such as MAC addresses, etc,. for you.
the two gratuitous ARP packages are comming from the DJI controller (Reply) and the sender MAC address was the correct one from the DJI controller. Therefore this looks fine!
Can you please send me a command to clear and add permanent ARP entries manually on the router? Then I can check if the ARP entry is correct and if not I can update or add it.
yesterday, I checked the ARP entries on the router and on my Windows client and all are showing the right MAC address of the DJI controller. Nevertheless I can´t ping the controller from the router or from my Windows client.
Do you have any other idea what could be the root cause that the DJI controller can´t connect to other devices on the same network? As already mentioned the same DJI controller get´s a connection on other WLAN networks, but not on the network of RUTX50.
I don’t have deep knowledge about remote drone controller’s and how it works. But you should be able to add manual ARP entries with below command from the CLI for RUTX50:
ip neigh add IP_ADRESS lladdr MAC_ADRESS nud permanent dev br-lan
For your question, I would want to look deeper if you can only see the ARP entries from the Windows PC and not from RUTX50 .
But now I suspect another issue that caused by the remote drone controller. Maybe it’s a configuration or something else.
Please try to add manual ARP entries and let me know about the result!
I have an important finding, which I would like share with you. I reseted the router to factory defaults and I started again with the configration. Per default IPv4 and IPv6 is enabled on the router and both DHCP services (IPv4 and IPv6) are enabled. The router is also sending out IPv6 Router advertisements.
If I connect the DJI controller to the WLAN network it gets a valid IPv4 configuration via DHCP and it also gets a few IPv6 addresses (link local (fe80…, unique local fd48… and public IP addresses).
Now I found out that I can access other devices on the same network via IPv6. I can also access the internet via IPv6. But I can´t access network devices via IPv4. My local streaming server has only an IPv4 IP address and therefore I can´t access it.
Is there a way that I can completely disable IPv6 on the RUTX50? I´m not interessted on an IPv6 configuration, because I would like stream the video ot the drone to a local streaming server which does only support IPv4.
From Network > LAN section of WebUI, you can disable DHCPv6 and there is also IPv6 Settings.
And also, from Network > DHCP you can change IPv6 settings. I also attached the screenshot of that window below.
