How to access host tun interface from a container?


I have a virtual interface internal (created with virtual = true; virtualType = "tun"; ipv6.address = "fd00:30::77"). The node-exporter is listening on it on 9100. Then I have two nixos containers prometheus (privateNetwork = true; localAddress6="fd00:30::a7") and grafana (privateNetwork = true; localAddress6="fd00:30::a9"). I want to make prometheus scrape node-exporter and make grafana access prometheus. The latter works without issues: I can curl prometheus endpoint. But I cannot curl the node-exporter endpoint neither from prometheus nor from grafana containers. If it matters, I use only ipv6 stack.

Please help. I lack the basic understanding why the connectivity is working between containers but not between the tun interface and container.