separation of authoritative and recursive functions on internal networks

Reindl Harald h.reindl at
Mon Feb 8 00:54:06 UTC 2016

Am 08.02.2016 um 01:00 schrieb Grant Taylor:
> On 02/07/2016 04:12 PM, Reindl Harald wrote:
>> define OK
> Will it cause any problems if the slave server is not listed as an NS?


>> for internal use NS records don't matter at all because the
>> only thing which matters is that the machines listed in /etc/resolv.conf
>> respond correctly
> I think I understand the intent behind what you are trying to say.  (NS
> (delegation) records aren't needed for internal zones -as long as-
> clients that use them are configured correctly.)

the clients ask your server or not, they are not doing recursion

> I do question the scalability of that intent.  If I expand the SOHO
> analogy to be a larger corporate + multiple branch offices scenario, I
> can see how internal delegation w/ associated NS records would be needed.

>> if it comes to the internet - it makes no sense have nameservers which
>> are not listed as NS records
> I disagree.


>> Warn     SOA MNAME entry     WARNING: SOA MNAME
>> ( is not listed as a primary nameserver at
>> your parent nameserver!
> My master name server,, is internet
> accessible, but it is not listed as a NS because I want all public
> queries to go through my slaves, ns{1..5}  Yet, people can
> direct queries to my master name server if they have a specific reason
> to do so.

that's not a reason for not list one of them as SOA

the salve don't need the SOA because it's typically configured to use 
whatever server as master which allows zone transfers, frankly you can 
even chain slaves pulling zones from other slaves

> I've previously asked Cricket Lou and Matt Larson, via Mr-DNS, if this
> type of configuration (having an Master Name server not listed in the NS
> records) is a problem and they indicated that it's not 100% ideal, but
> it will not cause any problems as long as the listed NS servers are
> accessible and used for delegation from the parent.  I.e. if your MNAME
> server is behind a firewall that will only allow the slave NS servers to
> communicate with it.
> What was your intent in pointing that out?  That has nothing to do with
> my original question.

that it's in general a good idea to use validation services and follow them

> Further, I don't see any response to my question, mixing recursive and
> authoritative resolvers in a SOHO scenario that is not internet accessible

the answer is: we are doing that for more than 10 years now

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