Maintained by: NLnet Labs

Prefetch threshold

Ralph Dolmans
Fri Dec 9 12:12:44 CET 2016

Hi Andrew,

So, you would like to serve expired data (with TTL 0) and use
prefetching to renew data before it expires? That is exactly what the
serve-expired option does.

This option is available in Unbound 1.6.0.

-- Ralph

On 08-12-16 20:56, Drew Rampulla (drampull) via Unbound-users wrote:
> Has anyone considered an enhancement to unbound prefetch to be able to
> configure the threshold to trigger when the prefetch runs instead of
> hard coding it to 10% of the TTL?  My intent was to handle cases where
> the DNS is unreachable, but still allow an application to continue
> working by using the previously known IP addresses.  So in my world I
> would set prefetch=yes, cache-min-ttl=1D, new_prefetch-threshold=1D
> minus 5 minutes.  In this way I would be able to refresh the DNS every 5
> minutes, but be able to work for up to a day without a valid DNS entry.
> Thanks,
> Andrew Rampulla