[PLUG] nscd

chris (fool) mccraw gently at gmail.com
Tue Oct 18 17:49:01 UTC 2011


On Tue, Oct 18, 2011 at 10:41, Paul Heinlein <heinlein at madboa.com> wrote:

> The first question I'd ask is, why is your local DNS resolver not
> caching the results. Most sites provide DNS TTLs of over an hour;

(site in question has an hour TTL set in its SOA record)


> For most sites, however, your local nameserver should return the
> address for a frequently asked hostname in just 10s of milliseconds.
>
> Who provides your DNS service?

google :( [8.8.8.8]

to be honest, i just realized what is going on.  i have a huge
download streaming in the background which is saturating my pipe, so
that *all* lookups that go over the wire are actually taking that
long.  i just wasn't noticing as much since my connection to gmail and
twitter is basically streaming or anyway less frequently connecting
and dropping.


> I know that Fedora and Red Hat are migrating away from nscd to sssd,
> which (afaict) is intended strictly for authentication caching and
> doesn't support DNS caching.

i came to understand that to be the main point of nscd too but used it
for dns caching since it was already running.


> Even on machines I manage that rely on nscd, I don't use it to cache
> DNS results. I'd rather setup a caching nameserver. Use aptitude to
> search for dnsmasq, a lightweight DSN forwarder.

thanks, i'll check out options along those lines.



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