- Added section on 'Hardware / DSL-Leitung' explaining the detected 17m branch line (Stichleitung) causing signal reflections and timeouts.
- Clarified that 'IP Flapping' was caused by stale caching of the previous day's IP, exacerbated by incorrect DNS settings (8.8.8.8).
- Finalized troubleshooting steps for Synology and FritzBox configuration.
- Documented the critical finding of hardcoded DNS (8.8.8.8) in Synology Network Interface settings overriding global DSM settings.
- Added comprehensive checklist for Synology, FritzBox, and Client configuration to ensure DNS stability and NAT loopback functionality.
- Updated log analysis section with 'NETWORK_WAIT' and 'ALERT' scenarios.
- Updated 'duckdns_setup.md' with critical instructions for configuring FritzBox DNS Rebind Protection to enable internal access (NAT Loopback).
- Added steps for clearing client-side DNS cache (Windows).
- Included Cloudflare DNS switch in documentation reflecting recent monitor script changes.
- Updated 'docker-compose.yml' with new DuckDNS token to lock out rogue updaters (FritzBox/HA).
- Enhanced 'dns-monitor/monitor.sh' to detect 'IP Flapping' (Zombie Updaters) by comparing Public vs. Global vs. Local IPs.
- Updated documentation 'duckdns_setup.md' with troubleshooting steps for IP flapping and zombie updaters.
