When we see a new peer or detect a restart (site_id change for known addr+port), send the announcement directly to that host via unicast instead of broadcasting to the multicast group. This avoids waking every other node on the subnet for a reply that is only relevant to one machine. The periodic multicast announcements continue unchanged for initial discovery. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>