Default PeerNet.NetworkMonitor implementation. Polls :inet.getifaddrs/0 on a configurable interval (default 5 seconds) and notifies subscribers when the local IP set changes.

What's filtered out

• Loopback (127.0.0.0/8, ::1) — never useful to peers.
• 0.0.0.0, 255.255.255.255 — degenerate.
• Interfaces in :down state — Erlang reports them, peers can't use them.

Probing

The probe function is injectable via the :probe option for testability. The default reads :inet.getifaddrs/0 and projects out a flat list of usable IPs.

Polling.start_link(
  probe: fn -> [{192, 168, 1, 50}] end,
  poll_interval_ms: 100
)

Subscribers

Subscribers can come and go. The polling process monitors each one and drops it from the dispatch list on :DOWN, so a subscriber crashing doesn't accumulate dead pids in state.