How can I increase the TTL for the cached entries in my local dns serveder?

Graham Clinch g.clinch at
Fri Mar 28 11:05:25 UTC 2014

On 28/03/2014 06:09, Hongyi Zhao wrote:
> In addtition, I also want to have long TTL so that I can obtain a short
> inquiry respond time.

Bind 9.10 might help in this regard - by refreshing cached records 
before they expire, rather than by faking their expiry time.  From the 
change log:

> 3703.   [func]          To improve recursive resolver performance, cache
>                         records which are still being requested by clients
>                         can now be automatically refreshed from the
>                         authoritative server before they expire, reducing
>                         or eliminating the time window in which no answer
>                         is available in the cache. See the "prefetch" option
>                         for more details. [RT #35041]

Note that 9.10 is still in beta (

Small nit for ISC - the download page suggests there is an ARM for 9.10, 
linking to - but that 
page contains the ARM for 9.9 (and thus, no details on prefetch).  The 
download for 9.10b2 does contain an ARM with details on prefetch.


Graham Clinch
Systems Programmer,
Lancaster University

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