Following the discussion about how ping fd20:0:1c::1 is reachable from a machine whose only local
presence is a /128 host address on a dc... TUN interface. The local (daemon) side is one half of
a point-to-point host-routed overlay; this doc walks the cloud/gateway half — how the tunneled
packet reaches the real VPC network.
- Your daemon creates a Linux TUN device (
/dev/net/tun), assigns your/128host address, and