Clear DNS cache from knot-resolver

Flush the Knot Resolver (kresd) cache on demand through its control socket with socat.

Updated 2026-11-12Sami Ait Ali Oulahcen

You can flush the Knot Resolver (kresd) cache on demand using socat to communicate with the running daemon:

socat - /run/knot-resolver/control/*

Inside the prompt type cache.clear()

> cache.clear()

You should get something like:

{
    ['count'] = 314182,
}
>

Type ctrl + C to exit.

If you run multiple kresd daemons. You might run into this error: socat[990255] E exactly 2 addresses required (there are 18); use option "-h" for help
In this case, You can clear the cache on one instance, and it will clear for all the instances because they all share the same cache database (LMDB).