High latency setting optimization

[Eric Luehrsen]

On 05/25/2018 04:53 PM, Simon Deziel via Unbound-users wrote:
> Having a local copy of the root zone using the auth-zone feature (or on
> a local NSD) might help a little.
> 
> On 2018-05-25 03:31 PM, Florian Lohoff via Unbound-users wrote:
>>
>> Hi,
>>
>> We are running multiple unbound caches behind very long latency
>> sat links. We are seeing RTT of at least 1000ms.
>>
>> Sometimes recursing times spike up to 20 Seconds.
>>
>> Is there an optimization guide on how to fine tune parameters
>> for those situations?
>>
>> I have already seen jostle-timeout. I am pretty shure prefetching
>> has a huge impact.
>>
>> Anything else?
>>
>> Flo

auth-zone: may be worth a try for sat. Trying auth-zone: on a broadband 
connection does appear to speed things up. The root zones ".", "arpa", 
"in-addr.arpa", and "ip6.arpa" NS respond to XFR. My conf example:

auth-zone:
   # Note root zone will be 2-3MB
   name: "."
   master: "a.root-servers.net"
   ...
   master: "m.root-servers.net"
   fallback-enabled: yes
   for-downstream: no
   for-upstream: yes
   zonefile: "root.zone"