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Demo DDNS Troubleshooting

Use this checklist when updates fail or DNS values do not match expected public IP.

Common errors and checks

Authentication failed (401/403)

  • Confirm CF_API_TOKEN is valid and not expired.
  • Verify token permissions include DNS edit for the correct zone.
  • Ensure the updater points at the intended DDNS_ZONE_ID.

Record not found

  • Verify DDNS_RECORD_NAME and record type (A or AAAA).
  • Check that hostname is inside the configured zone.
  • Confirm no typo in subdomain labels.

No updates are applied

  • Compare detected public IP with current DNS value.
  • Check interval settings (DDNS_CHECK_INTERVAL) are not too long.
  • Inspect container logs for dry-run or no-change behavior.

DNS still resolves to old IP

  • Wait for resolver cache expiry (TTL can still be cached by clients).
  • Query multiple resolvers:
nslookup home.example.com 1.1.1.1
nslookup home.example.com 8.8.8.8
  • Verify you are not testing against a cached local resolver.

Observability checks

  • Confirm container health and restart count.
  • Review last successful update timestamp in logs.
  • Alert if no successful update occurs within your expected interval window.