Does Unbound Load-Balance Stub-Zone?

George Thessalonikefs george at nlnetlabs.nl
Wed Jan 26 14:16:00 UTC 2022


Hi Steven,

I renamed that part of the documentation to make it easier to spot:
https://unbound.docs.nlnetlabs.nl/en/latest/reference/history/info-timeout-server-selection.html
There is quite some information there about how Unbound decides where to 
send a query.

Short version: Unbound does "load balance" based on the response time, 
prefers randomly picked fast servers in a certain time band (400msec) 
and keeps probing slow servers to see if they have improved their 
response time in the mean time.

Best regards,
-- George

On 25/01/2022 18:21, Steven Wills via Unbound-users wrote:
> Hello,
> 
> I have Unbound running with a stub -zone pointed at an NSD server. It 
> all works beautifully. I have gone through the documentation and do not 
> see an answer to this question. Does Unbound load balance between 
> addresses in a stub-zone? Meaning, if I had two NSD servers, and I put 
> both IPs into a stub-zone - would Unbound load-balance between the two? 
> I assume it would just use whichever server responded first, correct?
> 
> I ask because - if Unbound does not load-balance, I plan to use NGINX to 
> load balance like so -- Client > NGINX (LB) > Unbound Server > NGINX 
> (LB) > NSD Server.
> 
> Thank you,
> Steven Wills
> 
> 


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