1. Current stack: Nagios Core 4.4.14 with custom check_domain plugin polling whois servers directly. Fragile due to rate limits and output format changes.
2. Tried RackNerd's built-in alerts - only covers their own registrations, useless for multi-registrar setups.
3. Evaluated DomainMOD v4.22: decent UI, but requires manual CSV imports, no API sync.
4. Self-hosted solution: wrote Python script using python-whois 0.9.27 + SQLite, runs via cron every 6 hours. Emails at 30/14/7/1 days.
Practical recommendation: combine whois polling with registrar API where available. Standardize on 72-hour minimum lead time for critical domains to allow DNS TTL propagation during transfers.