Does 4G based OBD-ii device have mac or physical address? And alternative solution for restricting and whitelisting

Question

I know that almost all devices need a mac or a physical address to work with the Internet. I want to know that GSM-based devices like OBD-II have such addresses. We asked the manufacturer and they said, this type of device doesn't have that address.

We are creating a vehicle tracking platform and the devices are 4G-based OBD-II transmitting data on TCP protocol to the server. We want to do whitelisting of the devices. These devices have unique IMEI numbers, but we get those after the device sends hex data and we decode it. We want to check and restrict unknown devices from connecting to our server, but with the IMEI case they will connect and after the data decode we will know.

So if we know that those devices provide MAC or physical addresses we can implement Network security to restrict unknown devices from connecting to our server.

Please provide an answer whether this type of device has that address or not. And if anyone has experience with these devices suggest how to get these addresses from the device or an alternative solution for restricting and whitelisting.

Answer 1

A MAC address as found on Ethernet, WiFi, BLE, etc. is only visible when you are in the same L2 network, not across the Internet.

The only thing you will see at connection time is the source IP address, which will most likely be that of a NAT or proxy rather than specific to the equipment (and even if you get one from the device it will probably be dynamic).

The only way to filter the traffic is to have your device send the IMEI or other identifier in the payload (or, depending on the protocol used, in headers or during an authentication process for instance, or even a certificate of you use TLS). You won’t be able to filter at the IP level or lower.