Minimum TTL?

Karol Augustin karol at
Thu Feb 8 10:23:26 UTC 2018

On 2018-02-08 10:10, Michelle Konzack wrote:
> Hi,
> Am 2018-02-08 hackte LuKreme in die Tasten:
>> Is it possible to tell bind to ignore very short TTLs and enforce
>> a...say... 5 second minimum TTL?
> 5 sec minimum?
> What Du you mean with ignoring?
> It is you YOU have to configure Bind9 correctly to longer TTLs.
> If the NS Entry is not a Dyn-DNS entry,
> it should have anyway at least 3600 seconds.
This situation is relevant if bind is acting as recursive DNS server and
upstream record has very short TTL. In that case the record is not kept
cached for longer than 5 seconds and it might be not optimal if this
record is looked up frequently. Some recursive servers have an option to
set minimum TTL and thus overwrite upstream TTL for such records with
some minimal value (like 90s for example).

It has nothing to do with the authoritative mode when yo set up TTL for
zones locally hosted.


Karol Augustin
karol at
+353 85 775 5312

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