The 1800s minimum TTL defeated CDN failover mechanisms (e.g. Fastly
publishes 30–60s A-record TTLs specifically to signal when edge nodes
are removed). Dead IPs were cached for up to 30 minutes with no
way for the client to recover without a restart.
- Drop DEFAULT_POSITIVE_LOOKUP_CACHE_TTL from 1800s to 60s so that
CDN-signalled failovers take effect within a minute
- Shuffle resolved IPs on each lookup so retries cycle through all
available edge nodes rather than hitting the same dead address
- Add invalidate_preresolve_entry / invalidate_preresolve_for API
for callers that want targeted per-host cache eviction on hard
connection failures
Rachyandco
bf85e9eb79