Improving stability on Windows

[George Thessalonikefs]

Hi Aimee,

On 09/02/2021 00:01, Joe Abley via Unbound-users wrote:
> Hi Aimee,
> 
> On 8 Feb 2021, at 17:41, Aimee Miln via Unbound-users <unbound-users at lists.nlnetlabs.nl> wrote:
> 
>> I have just installed unbound on win10 as a simple DOT caching resolver. Although it seems to be working very well, there seems to be stability issues. For example yesterday I had to reboot my Internet router, once the router was back online, and Internet was restored, my DNS queries did not work on any of my home network, I had to restart the unbound service before it would work again. Today when I left home where DNS was working fine and I came into my office DNS also did not work. I had to restart the service again and it started working. I tested another device that had never previously used this DNS server, also would not work until the service was restarted
> 
> Unbound keeps track of authoritative servers that are unresponsive so that it can avoid overloading them with retries. It seems possible that during the brief period of disconnection from the Internet all of the nameservers needed to satisfy queries for particular names were all unavailable at the same time, and Unbound is avoiding using them for some period, following the same logic.
> 
> The infra-keep-probing and infra-host-ttl options in unbound.conf might be worth fiddling with if this sounds plausible.
> 
> https://nlnetlabs.nl/documentation/unbound/unbound.conf/

Based on what you describe I believe Joe is spot on on what is happening.
Along with fiddling the infra-* related options in unbound.conf, a more 
hard step is to use `unbound-control.exe flush_infra all`.
This instructs unbound to flush all the meta information it has on 
upstream servers.
That could also prove useful to verify that this is indeed what is 
happening in your case.

Best regards,
-- George

> 
> 
> Joe
>