Maintained by: NLnet Labs

[Unbound-users] caching server only

Jeroen Massar
Mon Dec 8 08:02:52 CET 2014

On 2014-12-08 07:44, Christoph Kaminski wrote:

> I want to setup a caching server only with unbound on each host what is
> able to 'survive' some time without the forwarder. Forward und reverse
> resolving should work. If it can reach the forwarder then it should ask
> there for all records (@/A/PTR/CNAME/SRV). If it cant reach the forward,
> then it should deliver the answers from cache. Is this config ok for this?
> server:
>         cache-min-ttl: 0
>         cache-max-ttl: 86400

The normal operandi of a caching DNS server like unbound is to query a
forwarder (or the root) only when the answer it has locally is already

TTLs for a lot of properties are very low (300 typically).
Hence, those records would expire very quickly anyway, likely quicker
than you do not want them to disappear.

Hence, default settings should work fine for you. Unless you want that
cache to persist for a longer time.

If you expect to have frequent outages of the forwarder though, better
to fix that situation...