4G extreme network traffic

Installation
1

I have a network traffic problem.
At my cabin I have a TP-Link TL-MR150 4G router, FW updated in september.
It’s a fairly simple HA installation, using cloudflared for remote access.
It all works very well, but:
The 4G network traffic is over the top. All the time. It will get close to 13GB in december, and I haven’t even been there. There are no web based services, everything is local, just a few temperature and lighting automations.

  • The Cloudflare dashboard says that the total bandwidth, last 30 days, is 736MB. Makes sense.
  • The TL-MR150 integration in HA says 9740MB in december.
  • My 4G ISP says I’ve used 10GB in december.

Could it be a NAT Loopback problem? My TL-MR150 doesn’t have NAT loopback functionality, I think (which is surprising and silly for a 4G router).
I’m very confused!
Experts, please: What is wrong?

2

Have you checked nobody is hijacking your router.

3

A valid and good question, since it seems like almost all the traffic is coming and going outside of cloudflare!
The cabin is 200 meters from the nearest house, so I don’t think any outsiders are connected to it.
When I try to ping the router’s public ip address, I get the response “Destination net unreachable”.
If I ping the domain name, I get replies from cloudflare, as I should.
How can I check if it’s being hijacked?

4

If your router can provide detailed logs, check them to see what traffic goes through to the airwaves.

5

Also if you can check if there are specific time windows traffic might spike.