Dynamic DNS fails

[Tom H]

On Mon, Mar 22, 2021 at 1:57 PM Ken D'Ambrosio <ken at jots.org> wrote:
>
> * 8.8.8.8 or the ISP's server, a caching server, maintains caches
> of entries so that it doesn't have to do a full query each time.
> (Windows clients also do this by default; Linux doesn't, but can
> with "nscd" -- Name Services Caching Daemon -- installed.) If it
> has an unexpired cache entry for the host query, it responds with
> that, and you're done.

If you ask on a list about using nscd, you'll most likely be told not
to do so because it's buggy. I don't know whether it's because there's
an anti-nscd cargo cult because of bugs in the past or whether nscd is
currently buggy. I last used it 15 years ago with nis and nisplus and
it was a PitA. But I have no opinion about it nowadays.

Current versions of Ubuntu have systemd-resolved enabled by default
and older versions had dnsmasq enabled by default. Caching's disabled
for these daemons by default, but it can be turned on. So there's no
need for nscd. You can also use kresd, named, or unbound as a local
caching server.