Maintained by: NLnet Labs

Prefetch threshold

Drew Rampulla (drampull)
Fri Dec 9 18:37:50 CET 2016

This is the perfect feature for me.  Do you know what the release schedule looks like for Unbound 1.6?  I see it is in RC now, but was looking for an idea on official release of 1.6.

Andrew Rampulla

On 12/9/16, 6:12 AM, "Unbound-users on behalf of Ralph Dolmans via Unbound-users" <unbound-users-bounces at on behalf of unbound-users at> wrote:

    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