[Unbound-users] Forward zone query distribution

W.C.A. Wijngaards wouter at nlnetlabs.nl
Mon May 18 14:14:59 UTC 2015


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Hi İhsan,

On 18/05/15 15:56, İhsan Doğan wrote:
> Hi,
> 
> I've got a question how queries are distributed to forward 
> resolvers.
> 
> In this example, I've defined that all queries, which can't be 
> answered from the cache, are forwarded to Google's DNS servers:
> 
> forwared-zone: name: "." forward-addr: 8.8.8.8 forward-addr:
> 8.8.4.4
> 
> How are the queries distributed between 8.8.8.8 and 8.8.4.4? Are 
> all queries going to 8.8.8.8 because it's the first one, are they 
> distributed via round-robin or is the one with the lowest response
> time getting the most of the queries?

Initially at random.  Then, once the response time is known, one of
the fastest ones.  It picks one at random from the "RTT band", so
small differences in response time do not matter.  If ping time to
those two IP addresses is roughly similar, then it'll end up as a
50/50 split.

There is a lot more logic, mostly for interoperability with
malconformant servers or servers with DNSSEC-bogus content.  But for
this example that would not make a difference.

Best regards,
   Wouter

> 
> 
> 
> 
> Ihsan
> 

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2
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=oxfK
-----END PGP SIGNATURE-----



More information about the Unbound-users mailing list