[GTALUG] Cache DNS issues.

[James Knott]

On 11/25/2014 12:08 PM, D. Hugh Redelmeier wrote:
> | From: James Knott <james.knott at rogers.com>
>
> | What's your cache time?  A cache will typically hold the data for a
> | short time, to keep stale data from propogating.  It might be as short
> | as a few minutes.  A cache certainly won't survive a reboot.
>
> I don't know about local policy, but each DNS record has a TTL which
> is supposed to limit the time it is cached.  I imagine that these
> are generally honoured by a caching server to avoid overloading the other 
> servers.
>
>

The original TTL was 24 hours.  But that's a bit long these days.  It's
a balance between "overloading" and stale addresses.  Upper level
servers tend to have long times, local ones shorter.  Regardless, I'd
expect the cache to be empty on a system that's just been started.

Cache as cache can.  ;-)