Flush DNS cache on Ubuntu, and what else caches
Flush the DNS cache on Ubuntu with resolvectl, then find the copies a flush misses: nscd, nginx, Docker, the JVM and stale or negative answers held upstream.
#systemd-resolved
Filtering by topic #systemd-resolved · clear
DNSSEC fails after KSK-2024 rollover (key 38696)
Lookups ending in SERVFAIL since 11 October 2026? Check whether your resolver trusts root key tag 38696 with the RFC 8509 sentinel test, then fix the anchor.