Constant data usage

Describe the problem

I am trying to use NetBird on my Android phone. However, it seems to just sip mobile data all the time. Changing to “force relay”, turning on lazy connections in the dashboard or Rosenpass on/off doesn’t change anything. This makes it unusable for me, as it easily can just use 2-3GB a day just by having it be turned on, and on my plan I only have 20GB of mobile data each month. I have isolated this data usage to NetBird. I’ve never had this issue with Tailscale. I cannot test this out on another phone, unfortunately. Is this expected behavior?

To Reproduce

Be connected to NetBird via the Android client.

Expected behavior

NetBird should ideally not drain my data permanently, and especially not this amount of it.

Are you using NetBird Cloud?

I self-host the control plane.

NetBird version
v0.4.1

Is any other VPN software installed?

No

Have you tried these troubleshooting steps?

  • Reviewed client troubleshooting (if applicable)
  • Checked for newer NetBird versions
  • Searched for similar issues on GitHub (including closed ones)
  • Restarted the NetBird client
  • Disabled other VPN software
  • Checked firewall settings

So, by going through logs, I found that one particular node (NetBird on HomeAssistant) was kind of spamming requests at my phone but was then turned down by the ACLs. Maybe I don’t understand how the ACLs work, but there is nothing allowing HomeAssistant to connect to my phone, so I don’t understand, why it even tries?
This is what I used to find this issue (adb on Arch):
PID=$(adb shell pidof io.netbird.client)
adb logcat --pid=$PID
Dropping local packet (ACL denied): rule_id= proto=UDP src=100.80.215.142:48645 dst=100.80.91.150:<random_port>
I have restarted the HomeAssistant node and now the data usage has dropped significantly, to almost none. I don’t really know if this was the actual cause, or if there was another issue that was resolved by restarting, but hey, it helped me identify the problematic node!