I am somewhat surprised there is not yet a feature that allows you to filter the incoming packets and drop the ones you don’t want.
I have been working with a packet forwarder that has a 4G modem and the goal is to forward the received packets from the connected devices to TTN. On its own it worked well with reliable telemetry data going from the device to TTN.
I then took a look at the data being sent so I could get an indication on how much cellular bandwidth was going to be consumed then realised that there seem to be a few other LoRa devices that don’e belong to me sending packets via the gateway/packet forwarded. Actually they were sending more data than my devices were.
My initial thoughts were that I need to look at changing the setup and run the GW as a server, then have the server send only the required data over the 4G link. but that also got me wondering as to why there was not a way to implement a filter on the forwarder that either looks at the device EUI and compares it to a list of allowed devices or even checks out the AppEUI.
If the EUI is not listed in the “white list” then the packet is dropped and not forwarded.
Using the AppEUI makes a little more as it is going to be a little more consistent in larger networks although the DevEUI is exposed in the header and would be easier to get at. Im not sure that the DevEUI is stored in the header.
Its really just a thought at this stage and I am quickly coming to the realisation that setting the gw up as a server may be the only way around this to prevent unwanted packets from being sent over the 4G link but it also adds a level of complexity as all the GW/Sever devices will need to be updated with the device’s.