On 11/25/2014 12:08 PM, D. Hugh Redelmeier wrote:
| From: James Knott <james.knott@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. ;-)