[Pdns-users] pdns-recursor delegate some queries to another recursor

[Nico CARTRON]

Hi,

On 20-May-2019 16:04 CEST, <pdns-users at mailman.powerdns.com> wrote:

> > wonder if the following is possible somehow with pdns-recursor. Our main
> > recursor A sometimes has problems talking to some auth servers. In the
> > same time another recursor B in our network still can talk to such an
> > auth server.
> > 
> > So we wonder if we could somehow send queries for such auth servers via
> > the other recursor. The decission to send queries to the other box is
> > based on the IP address of the auth server. The idea is to route such
> > queries from recursor A to recursor B while all other queries from
> > recursor A should still be sent without recursor B.
> > 
> > Is something like that possible in pdns-rescursor or do we have to use a
> > tool like dnsdist?
> 
> Hi Tobi,
> 
> I recommend using dnsdist for this use-case! Sending traffic to backend dns
> servers is what dnsdist is made for!

While it's true that what Frank suggested is totally doable with dnsdist (and
actually one of its missions), it would be interesting though to understand why
one of your recursors has issues to reach the authoritative server, and another
recursor has no issue.

A couple of questions:
- are they running the same Recursor version?
- are they on the same network / same site / faced by the same network
  equipments, if any (e.g. firewall) / any ACL in place
- which OS are they running (if differences between the 2)

Cheers,

-- 
Nico